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andrewr
10th Apr 2017, 11:08
An interesting item in the latest Vic RAPAC minutes.

Someone - perhaps unwisely - asked CASA for clarification of operations above 40 degrees C, given that the performance information in many flight manuals only goes up to 40 degrees.

"if an aircraft's AFM caps performance data at 40C, can the aircraft still legally fly when the ambient is above 40C?"

CASA's response:
"If ambient conditions exceed ... the range for which performance data is provided, the aircraft must be grounded"

I'm not sure whether the person who wrote that has actually looked at the performance data provided in a typical flight manual. There are many conditions for which no performance data is provided, so a prohibition on operating in conditions without performance data is not exactly workable.

Looking at e.g. a C172 manual, there is no performance data for any of the following:


Flaps 0 takeoff
In fact, nothing for normal takeoffs and landings - all performance data is for short field techniques
Any runway slope
Wet grass etc.


Common sense seems to have left the building

https://www.casa.gov.au/files/vic170323pdf

Squawk7700
10th Apr 2017, 11:32
My mate in central WA is going to be in strife, he regularly flies in temps closer to 50 deg!

Flying Binghi
10th Apr 2017, 11:45
Hmmm... is this 'advise' dated April 1st ?

As far as i'm aware, Ambient temp is where yer standing and is not in any met reports. So in the middle of sumer standing next to yer aircraft in the middle of a large expanse of hot bitumen it would likely go past 40º even when the met says 35º.





.

Jabawocky
10th Apr 2017, 11:48
Just like all the POH's that describe one thing on one page, yet turn the page and the engineering data clearly says the opposite. You can't do both, so which do you trust?

Critical thinking is required folks, something many at CASA are incapable of doing, and demonstrate it regularly.

MJA Chaser
10th Apr 2017, 12:18
Measured where by who?

andrewr
10th Apr 2017, 12:44
Measured where by who?

Presumably where-ever you are supposed to get the temperature from for your performance calculations.

OAT gauge, ATIS, AWIS, forecast... possibly even declared density?

Ia8825
10th Apr 2017, 12:54
Measured where by who?

By the pilot wherever they can get a temperature reading that makes it legal to fly.....

TBM-Legend
10th Apr 2017, 12:57
Saab 340B engine start limit 47C so at Birdsville eg. a clever fast look at the temp got you going..

triadic
10th Apr 2017, 13:21
In one middle east country, I hear that the temp never goes above 50c as that is when the tarmac workers have to stop work!! Helps keep the aircraft flying as well......

Duck Pilot
10th Apr 2017, 20:52
At Weipa they once used sprinklers on the tarmac to prevent it from melting.

Essentially you can't operate any aircraft legally if the AFM doesn't have performance data to support the conditions.

I once worked for a company in PNG who owned two Bell 412s, the AFM only had P charts to support ops below about 8000 ft, which technically prevented us from using the machines at high altitudes. Only solution was to purchase high altitude P charts from Bell which come at a cost.

Similar situation with some GA fixed wing aircraft in PNG, however most operators never bothered getting amended P charts.

Sunfish
10th Apr 2017, 23:16
So at 39.99 degrees you are good to go, but not at 40.1? Makes sense really.

andrewr
10th Apr 2017, 23:57
Essentially you can't operate any aircraft legally if the AFM doesn't have performance data to support the conditions.

So in the example of a C172, is it illegal to use the AFM documented normal takeoff or landing procedures? There is no performance data for them.

What about wet grass? A runway with a slope?

outnabout
11th Apr 2017, 00:37
Someone - perhaps unwisely - asked CASA for clarification...


AndrewR - and that's when the fight started!


(In my opinion, it is Very Unwise Indeed to ask for clarification....particularly from the Cherubs Against Sensible Aviation.)

no_one
11th Apr 2017, 00:51
Extract from the SR22 POH. I have added the bolding


Associated Conditions Affecting Performance
Computed performance data in this section are based upon data derived from actual flight testing with the airplane and engine in good condition and using average piloting techniques. Unless specifically noted in the “Conditions” notes presented with each table, ambient conditions are for a standard day (refer to Section 1). Flap position as well as power setting technique is similarly noted with each table.

The charts in this section provide data for ambient temperatures from -4°F (–20°C) to 104°F (40°C). If ambient temperature is below the chart value, use the lowest temperature shown to compute performance. This will result in more conservative performance calculations. If ambient temperature is above the chart value, use extreme caution as performance degrades rapidly at higher temperatures



and


Demonstrated Operating Temperature
Satisfactory engine cooling has been demonstrated for this airplane with an outside air temperature 23°C above standard. The value given is not considered an operating limitation. Reference should be made to Section 2 for engine operating limitations.


So even though the performance data is only given for temperatures up to 40 degrees the POH wording makes it clear that operation at higher ambient temperatures is not prohibited.

Car RAMROD
11th Apr 2017, 02:21
Would one be able to contend that if there is no explicit temperature in the limitations section, that the "40 deg limit" obtained from the P charts might not actually be a limit?

andrewr
11th Apr 2017, 02:40
I am sure that is what the manufacturer intended, however CASA has said

"If ambient conditions exceed ... the range for which performance data is provided, the aircraft must be grounded"

no_one
11th Apr 2017, 02:45
In the SR22 POH they don't provide takeoff distance data for less than 0 degrees C. Does CASA really mean that the aircraft can't fly in temperatures less than O degrees C?

Car RAMROD
11th Apr 2017, 02:47
Andrew, yes, but they are not always correct. I'm sure you've probably experienced it.

Are aircraft to be grounded when the crosswind is greater than the demonstrated maximum?

If a place is hotter than forecast when you arrive overhead, and outside the P chart temp, they say you cannot land. Must the PIC now declare an emergency? Or will we have to hold alternates for the temp being too hot? Nothing in the AIP about that under alternate requirements!

djpil
11th Apr 2017, 02:59
My guess is that CASA partly, at least, bases their opinion on CAO 20.7.4 which changes the scope of this discussion.
e.g. " An aeroplane must not take off at a weight in excess of the least of the weights determined in accordance with subparagraphs (a) to (d):
(a) a weight at which the take-off distance required under subsection 6 for the pressure height, temperature, runway slope (if in excess of 1%) and wind component along the runway, is equal to or less than the take-off distance available in the direction of take-off. Approved declared conditions may be used instead of actual pressure height and temperature ..." etc.
i.e. if the performance information stops at 40 deg C (per FAR 23) then how can the pilot show compliance with CASA performance requirements at higher temps .....

Car RAMROD
11th Apr 2017, 03:16
The CAO argument is interesting.
It says you cannot take off at a weight greater than that determined from the P charts. But what if you cannot determine a weight?

You might not be able to show compliance, but can CASA prove, based on the same (lack of) performance information that the plane wouldn't perform?

Is there a specific regulation that explicitly states that you cannot operate outside the P chart figures?

Im just being a little bit of an advocate for the devil; I'm not necessarily brave enough to take on the potential battle.

My other question is- why only now does CASA say that you cannot operate when the temp is outside the P chart temperature? They've been in existence for decades, and it's not a new idea.

john_tullamarine
11th Apr 2017, 04:18
Further to djpil's comments ... the important thing is can you argue your case satisfactorily if push comes to shove and you find yourself in court for whatever reason ?

So far as performance is concerned, provided there is not an OAT limitation in the limitations section of the POH, one can always get the charts redone to suit your operational needs.

megan
11th Apr 2017, 06:26
Just an observation that perhaps CASA are drawing on this section of the FAR§23.45 General

(a) Unless otherwise prescribed, the performance requirements of this part must be met for—

(b)(2) For reciprocating engine-powered airplanes of 6,000 pounds, or less, maximum weight, temperature from standard to 30 °C above standard
§23.1583 Operating limitations

(n) Ambient temperatures. Where appropriate, maximum and minimum ambient air temperatures for operationSome aircraft have a piece such as this in the limitations sectionAMBIENT TEMPERATURE LIMITS
-34°C (-30°F) to ISA plus 37°C not to exceed 49°C (120°F).Piper and Cessna, and others, have adopted the standard + 30 approach, with charts only going to 40C.

Question is, are you breaching the law by operating in temperatures above the certification standard when there is no limitation in that part of the manual?

Of course if you do the result can be

https://www.youtube.com/watch?v=OVM3RRd1vf0

clear to land
11th Apr 2017, 08:30
I remember in a previous life flying a King Air 90 into YWDH. Temp on the OAT gauge was ISA+ 42 so I told the pax we will sit in the shade and waited for the gauge to show ISA + 39. This was my decision based on the fact that IF something went wrong it would be MY fault for operating outside the certified envelope. Ultimately its a Command decision-but to operate outside the certified envelope is incredibly poor Airmanship unless under EMG/Mercy Flight conditions.

andrewr
11th Apr 2017, 09:01
How would you determine the runway required for a normal takeoff (no flaps) in a C172 at sea level, 15 degrees C?

Derfred
11th Apr 2017, 10:14
I'm no lawyer, but CASA's insistance on "strict liability" clauses in virtually every regulation they produce makes a pilot's position quite clear. If you have an accident, and a possible/probable cause of the accident was a breach of a "strict liability" regulation, then you are in serious trouble.

Now the minutes of a RAPAC meeting do not constitue a strict liability regulation.

But if you do ding one in operating outside of the available performance data, and CASA believe that that was a contributing factor (and I'm sure they will try hard to do so), then you may fall foul of one of their "strict liability" regulations unless you can prove some reasonable means of compliance (kind of making you guilty unless you can prove innocent, which goes against most modern legal justice systems).

But also, don't ask a question unless you already know and like the answer. What else did they expect CASA to say: eg "yeah, no worries, just take off anyway, just don't ding it in..." :)

I'm sure a Pprune bush lawyer will pick apart what I've put, but that's my basic interpretation.

djpil
11th Apr 2017, 10:50
More straightforward when we had the Australian specific DoT AFMs but they've been discarded and the requirements of CAO 20.7.4 re soft dry grass and runway slopes don't fit with an older typical FAR 23 AFM or POH and the weasel words in the CAO are not enough to hang your hat on.

Nil authority to continue to use those old P charts, if you do then you are personally responsible - I asked CASA to provide the test data and analysis for the 8KCAB Decathlon and got nowhere. I suspected that some bright person had provided an 8KCAB with 180 hp and C/S prop for the performance testing - where did that leave me with an 8KCAB fitted with the standard 150 hp and FP prop? The P chart is simply labelled 8KCAB. Manufacturers info? - that's another story.

Cessna Jockey
11th Apr 2017, 10:53
Interesting question and a lot of focus on the POH...

I'm no stranger to GA in hot climates, but perhaps the question some should be asking is "how long can my human body perform in 40+ degree temperatures without a whiff of air conditioning in a c172". I've done some fairly stupid things when I've been hot and dehydrated, and when that door shuts and the sweat starts dripping, don't expect your mental capacity to be at an all time high.

Pinky the pilot
11th Apr 2017, 11:30
I can remember years ago taxiing in a Chieftain at YBDV for final destination YBOU (with stops at Roseberth and Durrie Stations) with the OAT gauge reading 48C.

On arrival at YBOU the OAT read 51C.

Struth Johnno;(if you are reading this) How did we survive this????:eek::rolleyes:

kaz3g
11th Apr 2017, 11:50
I'm kinda glad that the AUSTER doesn't have an AFM or a POH.

Kaz

Lead Balloon
11th Apr 2017, 12:10
Your decades-long trail of dangerous operations have been noted, kaz. :}

KittyKatKaper
12th Apr 2017, 00:34
I'm now wondering how the old Perf charts were created.
Looking at the Takeoff Performance chart for a PA28 I see that the OAT region goes from -40'C to +40'C, but I seriously doubt that the PA28 was actually tested at -40'C.

Performance is determined from the Pressure (Density) Altitude.
The problem is that DA is non-linearly dependent on OAT.
Back in the 60's it was easier to pre-calculate a nomograph for the 'expected' operating range and +40'C seems like a reasonable upper limit for the USA at that time.
Now if I can determine what the DA actually is (from an expanded pre-calculated DA v OAT chart, or from a formula), then I can apply that DA to the Perf chart and on that basis the 40'C 'limit' is no longer a limit.

Unfortunately we are talking about CASA and their ineffable bureaucratic wisdom, so common-sense is not allowed.

djpil
12th Apr 2017, 00:53
FAR 23 has rules about the limits for extrapolating test data to higher or lower temps and altitudes.

They (we at times) used to do a short series of takeoff and landing tests at a place like Bacchus Marsh and a fancy (for then) computer program would print those P charts.
Charts also for climb performance limits apply to some types - remember that little line on the C150 P charts derived from a goround with flap down.

Just can't wait until an FOI rocks up for some refresher training.

601
12th Apr 2017, 01:29
My other question is- why only now does CASA say that you cannot operate when the temp is outside the P chart temperature? They've been in existence for decades, and it's not a new idea.

I'm not necessarily brave enough to take on the potential battle.

Had an experienced back in the 70s where an aircraft departed in high temps 40+ but with a 20Kt wind that allowed a shorter, but into wind, runway to be used.

The Alphabet Authority (cannot remember what they were called at that particular point of time) tried to ping the pilot for departing of the runway as it was too short based on the "P" charts that only presented calculations to a temp of 35c and a wind less that the actual wind.

But using the manufacturers charts the aircraft could depart. The Alphabet Authority pointed out that we had to use the "P" Charts. I informed the Alphabet Authority that their "P" charts did not reflect the conditions experienced in Australia and therefore we were being forced to use charts unfit for purpose.

I did not hear back from Alphabet Authority.

aroa
12th Apr 2017, 02:28
Lucky Kaz...all operating Auster stuff in the brain database. No book.

I have some Auster type AFMs.... J2, J5F etc. Not heavy duty tho.

8. Glider towing.
Fly as normal.

Simple and sound advice.

Icarus2001
12th Apr 2017, 04:09
So at 39.99 degrees you are good to go, but not at 40.1? Makes sense really.

Of course. Same as if MTOW is 2800Kg. You are good to go at 2800kg but not at 2801kg.

Go in to a pub the night before your 18th birthday, fly a charter before your new licence is issued...

Blah blah blah. There is always a line somewhere.

Ask this CASA guru for WRITTEN confirmation of this OPINION.

and CASA believe that that was a contributing factor (and I'm sure they will try hard to do so)

Yes but it the ATSB who would determine that.

john_tullamarine
12th Apr 2017, 04:15
I'm now wondering how the old Perf charts were created.

Further to djpil's comments ..

In days of olde .. when we had local rules (ie pre-Yates Report changes), one could either do one's own thing (ie develop equations or use the standard FT equations) or use the DCA equations (presented in an in-house document to which Industry consultants had access). Needless to say, most folks used the DCA document as that avoided much discussion in the approval process.

The DCA document (I have a copy but can't recall the ID without digging in the archives for it ..) used some pretty simple equations but, in practice, they were of sufficient accuracy that the P-charts were a reasonably good mix of a little conservatism and accuracy.

Later on, the document was revised the better to take account of turboprop performance .. and that document was a different beast altogether .. so, we ended up using the old stuff for pistons and the new stuff for turboprops.

The equations allowed for the interpolation (and limited extrapolation) of whatever data set had been captured .. not too much in the way of extrapolation as that involved a leap of faith .. interpolation was much more defensible. So far as test programs were concerned, we normally tried to get low/high and hot/cold within the realms of reasonable possibility and take it from there. Obviously, the more test data, the more accurate the end charts could be. What variable range ended up in the charts depended a lot on what range of test data could be found. This is no different to the problems faced by Mr Boeing and others ..

At the high end of the spectrum, for data capture, one could do cinetheodolite performance takeoffs and landings which provided a movie tracking record of the aircraft (allowing corrections for camera unit mistracking) and azimuth/elevation data for the camera axes (paper trace .. great fun working with that stuff).

Accurate survey data was required for the runway and camera unit position to do the geometry sums.

From these records, one could spend copious numbers of (relatively) productive hours developing a very accurate time history of the takeoff/landing distance and air distance/height. This allowed speed and acceleration data to be determined to a very good accuracy if you had a need for that sort of stuff.

Unfortunately, back in the 60s/70s, this equipment was pretty high tech (and expensive) so only the military and the likes of GAF were able to use it. Djpil and I spent numerous hours in the Fishermens Bend sweatshop doing this stuff after Nomad flight trials. Also, I had fun doing similar stuff at ARDU for a while.

Once we get out into the GA world, though, no-one was likely to have this kit sitting around waiting for some trials so the local industry, with DCA, developed a much simpler exercise using a reasonable quality still camera to take a series of exposures to get the important sections of the takeoff and landing. Not quite as accurate as the CT .. but much quicker and more than fit for purpose.

Some folk, to save on dollars, did the exercise with constant (gross weight) speeds throughout (reduced the number of flight trials required) and that produced some strange results in the P-charts which were the occasional subject of bar room discussions. For example, one saw landing P-charts where the distance increased with reducing weight (due to float at the end of the landing flare)

On occasions, if the OEM data in the POH appeared defensible, one would negotiate with the DCA gurus of the day and, sometimes, take a few points from the OEM POH data and use those to develop the P-charts.

DCA had a nice little HP plotter gadget to run up the charts .. most of us out in the Industry did it by hand .. same result... the typical P-chart presentation was dreamed up by DCA (Ron S, perhaps ?) and was just one of a range of possible presentations. It has its good and bad points, like any presentation. I did my share of GA P-charts and, I guess, so did djpil

Do keep in mind that this all predated the first of the microprocessor computers which came onto the market in the mid-70s - prior to that, if you could afford it, there was the odd TI bit of kit which allowed some number crunching capability. Needless to say, none of us had private access to the few mainframes around the place.

Spare a thought for us back then .. a computer (with a capability inferior to a modern pocket calculator, along with printers, cost me around $20k in the mid-70s but could we do things with that primitive kit compared to an old (still quite expensive) TI programmable calculator or slide rule. Would you believe I managed to upgrade the system several years later when a 5 kb hard drive came onto the market. (Maybe it was 5 mb .. whatever, it was tiny)

Aussie Bob
12th Apr 2017, 11:54
Cue Presidents of the USA ...

"We're not gonna make it"
"No no we're not gonna to make it"

I could well have sung this as I staggered out of Maitland Airport's runway 26 on a day well north of 40C in an old 6 cylinder 172 just shy of gross.

Somehow I drifted left to avoid old mates lounge window half way up the hill while observing the cushions on his couch. This was while planning on going under the power lines and performing a controlled crash up the slope in a clear area. While this was going on and in a state of sheer panic I somehow managed to glance at my mate next to me, intending to give him a crash brief only to discover he was engrossed in a magazine and completely oblivious to the situation. A serious slow motion event, he never did get the brief.

Somehow we made it over the hill, but it took several hours afterwards for me to regain composure and it was an event I will never forget.

Some aircraft should definitely be grounded at 40C.

Nipper
12th Apr 2017, 12:13
Don't ask CASA, ask your Insurance Company, they will take greater interest in the ambient conditions should you fail to defy gravity.

andrewr
12th Apr 2017, 13:58
Ask this CASA guru for WRITTEN confirmation of this OPINION.

It is in writing, in a letter attached to the most recent Vic RAPAC minutes.

We are not talking about a 747 or even a King Air where you probably do have performance data for every takeoff. The reality is, smaller aircraft are operated outside the parameters of the performance charts all the time, by necessity.

The C172 performance data goes to a density altitude of something like 12,000'. Why is it OK to operate at Mt Hotham at 35C, but not Mildura at 43C?

Density altitude was part of the PPL theory. You can in fact predict the effects with reasonable accuracy. CASA actually do that in the declared density charts. Maybe you just need to break the OAT and use the declared density?

The letter from CASA is actually claiming that the ranges specified in the performance charts forms part of the aircraft limitations. Which also suggests that the aircraft must be grounded below 0C.

djpil
12th Apr 2017, 14:41
I'm now wondering how the old Perf charts were created. I did my share of GA P-charts and, I guess, so did djpilI did some a little while ago at Point Cook using a video camera ...
https://www.casa.gov.au/files/vic170323pdf for that letter from CASA.
Want to do some more, JT?

djpil
12th Apr 2017, 22:08
Density altitude was part of the PPL theory. You can in fact predict the effects with reasonable accuracy.doing it right per AC23-8 and noting the appropriate use of fudge factors for conservatism - notes in Appendix 2 partly explains the reasons.

The letter from CASA is actually claiming that the ranges specified in the performance charts forms part of the aircraft limitations. Which also suggests that the aircraft must be grounded below 0C.Yes indeed, and their general statement: "This means that a pilot must not operate an aircraft outside the limits set out in the AFM, including limits set out by the ranges of the parameters on the performance charts." has broader implications, not just the temperature range - take the PA-28-161 for example:
- pressure altitude - lower end of the range is sea level so if the QNH is higher than 1015 at an airfield close to SL then we're outside the range of the performance chart. Today is 1024 at YMMB so all Warriors must be grounded all day.
- maximum headwind on the chart is 15 kts so if the wind is straight down the runway at 17 kts then they can't fly but 17 kts across the runway is fine.

Perhaps everyone should write to CASA asking these related questions?

Meanwhile Kaz and I shall continue to fly undisturbed - my airplane's AFM has no performance information at all.

megan
13th Apr 2017, 01:47
This type of argument has been had in the helicopter community. All helos have what is called a height/velocity diagram, for FAR 29 it's in the limitations section, so you can't operate inside it. Others, such as Bell 206 class (FAR 27), have it in the performance section and merely give the advice to "avoid". Guess where those helos spend a lot of their time operating?

Flying Binghi
13th Apr 2017, 03:20
via Megan: ...All helos have what is called a height/velocity diagram, for FAR 29 it's in the limitations section, so you can't operate inside it...


Eh!... do that mean all of them crapy robinson 22's are banned from mustering...:cool:





.

megan
13th Apr 2017, 03:34
Hate to tell you FB, but R-22 is FAR 27, so fill your boots inside the H-v.

john_tullamarine
13th Apr 2017, 05:47
Want to do some more, JT?

Always open to suggestions, good sir ...

The reality is, smaller aircraft are operated outside the parameters of the performance charts all the time, by necessity.

If the operation is on the conservative side, I can see it being argued without too much difficulty .. but not everyone has the background to do the sums and argue the toss.

If the operation is on the non-conservative side, things could get a little difficult after the event.

Others, such as Bell 206 class (FAR 27), have it in the performance section and merely give the advice to "avoid".

Given the effort that goes into developing a limiting dead man's curve, and the risks associated, needless operation within is a bit on the scary side if something goes bang ... (while noting Megan's extensive rotary background).

megan
13th Apr 2017, 06:25
needless operation within is a bit on the scary side if something goes bangIndeed, that's why they paid us danger money - I wish, twice had things go bang, one no event, the other didn't know if we were to live or die for a brief few seconds. Even FAR 29 used in off shore oil operated inside the curve for a period of time during landing/take off despite the curve being in the limitations. That was got around by declaring it a Category "B" operation where accountability was not required, but observance of the curve was, Category "A" required full accountability. All legal, in as much as I asked CASA about the exposure inside the curve and had a reply in writing to the effect we think there is some dispensation somewhere but we can't find it.

john_tullamarine
13th Apr 2017, 09:18
.. sounds like you were lucky on both occasions ...

kaz3g
13th Apr 2017, 12:49
DJPIL said...


- maximum headwind on the chart is 15 kts so if the wind is straight down the runway at 17 kts then they can't fly but 17 kts across the runway is fine.

Perhaps everyone should write to CASA asking these related questions?

Meanwhile Kaz and I shall continue to fly undisturbed - my airplane's AFM has no performance information at all.

So the AUSTER allegedly has a demonstrated max crosswind of 9 knots. Does this mean I can land across the runway if the crosswind is greater than 9 knots?

Kaz

Obidiah
13th Apr 2017, 14:48
In defense of CASA if I were in their position and asked somewhat informally if operation beyond the max published 40 degree temp was legal I too would probably say it isn't. What is the benefit to say otherwise?

Just the same as I would respond to the question if it were asked if it is legal to T.O. below 0 degrees as this is the minimum listed temp in the P charts(1978 C182RG POH).

Of course applying common sense you will likely arrive at a different outcome particularly as 40 degrees T.O./LDG is permitted at 8000' PH with a QNH of 980 hpa (same POH)

Piltdown Man
13th Apr 2017, 22:27
I think there is a misconception about the charts. Basically, you may not operate outside the limitations of the aircraft and/or extrapolate beyond the performance limits of your aircraft's performance charts. This means if you have 50 knots of headwind, you can only use 15 or 20, depending on which charts you have. Similarly, if you operate below sea level, you may not claim any benefit for doing so. However, if you have a temperature above 40 Celsius and that it where your charts stop then it's time for a cold beer. Yes, people do fly beyond the performance limits of their graphs and some fly after a wine or five. But both are still illegal.

PM

john_tullamarine
14th Apr 2017, 00:36
ie conservative and non-conservative extrapolation and appropriate usage ..

andrewr
14th Apr 2017, 00:47
The C172 takeoff performance charts for MTOW specify lift off at 51 KIAS and initial climb at 56 KIAS.

Most people would use the Normal Takeoff procedure, which is raise the nosewheel about 55 KIAS and climb at 70-80 KIAS.

Will this use more runway? Definitely.
How much more? A lot more.
Exactly how much more? No idea - there are no performance charts covering a Normal Takeoff.

If you the chart doesn't apply to your takeoff (using the manufacturer specified procedures), what is the point of grounding the aircraft when you are outside the temperature bounds of the chart?

The distances in the performance chart are very short.*

The reason we don't have PA28, C172 etc. running off the runway is not because people religiously use performance charts - it is because we use long runways and most people are not comfortable with less than 2-3 times what the performance chart specifies.

*Examples from the C172 chart:
Mildura, 40C, MTOW: ground roll 385m, 50 ft 600m. Add your Australian 15% gives you 700m to 50 feet.

Mt Hotham, 30C, MTOW:
520m ground roll, 910m to 50 feet. (+15% = 1050m to 50 ft)

andrewr
14th Apr 2017, 01:00
conservative and non-conservative extrapolation and appropriate usage

Based on the density altitude calculations we were required to learn for PPL, my approach would be to use a higher altitude/lower temperature giving the same density altitude and enter the chart that way.

That appears to be conservative because engine power reduces faster with altitude than with temperature, so higher altitude/lower temperature should give a longer distance.

However, given the short distances in the chart I probably wouldn't take off if the runway available wasn't significantly greater than what was calculated.

megan
14th Apr 2017, 02:27
Basically, you may not operate outside the limitations of the aircraft and/or extrapolate beyond the performance limits of your aircraft's performance chartsAs an example of the problem I cite the Cessna 404 manual. The take off charts only go to 40°C, but the climb charts (both dual and single engine) go to 50°C, and the sea level cruise performance only goes to 35°C.

If 40C is the max for take off, why the 50C climb?

What CASA are saying now is that 35C then becomes the limiting factor in operations. Which we know is bollox.

This is the CASA solution (not published in the meeting minutes),Unless a safety concern exists, it is not CASA's responsibility to compel OEMs, TC/STC holders, etc to amend information included in the AFM. If there is operational need for data beyond the ranges included in the AFMs, an operator may explore if extending those ranges is possible by contacting the OEM, relevant design organisations, etc. If this results in a change to the AFM, then that change will be approved as discussed above. Any cost of such change to the AFM will likely fall on the operator initiating the change.The above is signed by a Rob Walker, CASA Stakeholder Engagement Group Manager. What is his background?

Personally, for the take off I would work the problem hence,

OAT 50°C @ sea level = 4,000 DA = 1,000 PA @ 40°C, since DA is what influences performance. I would be interested in djpil and JT comments.

john_tullamarine
14th Apr 2017, 02:33
Most people would use the Normal Takeoff procedure

Providing the length substantially exceeds the standard data, and the terrain profiles are benign, the normal takeoff can be converted into the standard speeds should a need arise.

How much more? A lot more

To a rough first approximation the distance ratio will go up as the speed ratio squared eg speed up 20%, then distance up probably in excess of 45%

it is because we use long runways

Indeed .. which is why the problems arise when folks, used to long runways, find themselves playing out in the woods with seriously short strip lengths. The croppies and tug pilots, having had some training and exposure to these concerns, generally show a high degree of conservatism .. if they are to survive to retirement age.

my approach would be to use a higher altitude/lower temperature giving the same density altitude and enter the chart that way.

On what basis ? Not being wary of extrapolating to higher elevations and OATs might present problems. Things aren't necessarily linear.

For the typical non-engineering pilot, I would suggest don't extrapolate high. If the elevation/temperature is lower than the the chart data, and there are no other systems limitations prescribed in the limitations section, maybe .. and, in that case, use the published data without trying to take advantage of extrapolation.

I would be interested in djpil and JT comments.

I think Dave and I would opine along the lines that we would, first, like to know a bit about the aircraft's engines, airframe configuration, etc ... ie better not to wing it on the fly as it were .. Mr Walker's (and I have no idea who he is) comments are the go .. as I suggested earlier, if the operator has a problem with the POH, do some accredited testing and reschedule the performance data .. get a tick in the box .. and Robert's your parent's sibling.

thorn bird
14th Apr 2017, 03:57
All this suggests to me that either:

1. Our regulator is hell bent on wiping out all forms of aviation beyond RPT or the military, who by their size, political power and financial resources are somewhat immune to the imposts of overregulation. For nefarious reasons we stakeholders at the bottom of the pile could never comprehend.

2. Our regulator like their regulations are infested with inane concerns for legal liability, blinding them to practical, common sense solutions to risk management.

3. Is it time to swallow our pride and accept that the rest of the world is not necessarily wrong, anymore than we are not necessarily right?
Accept that our regulator in their arrogance and ineptitude has embarked on a folly that has bought ruin to an industry and has achieved none of the aims set for it by government and squandered vast sums of public money on a myth for no appreciable return?
Is it time to embrace the best of the rest of the world while there is still a chance to prevent an industry from complete collapse?

From the time we get out of bed every facet of our daily life carries risks which we must choose to manage, or not as is our wont, its called freedom of choice.
Our bureaucrats have taken it upon themselves to attempt via the criminal code, in our industries case, to legislate common sense thus closing off any likelihood of liability falling on them or the government for every choice or action we may choose to take. We see this not just in our own industry, bureaucrats are meddling in almost everything we do in our daily lives.
Trouble is, the more they meddle, the more the "unforeseen"consequences of their meddling needs to be addressed, creating a never ending cycle of action and reaction, creating ever mounting restriction and cost.
For aviation, overlaying all this is the self interests of all the parasitic industries that have sprung up to feed off the aviation industry as a result of bureaucratic meddling. The security Industry, big banks who control our major airports, development sharks who control our secondaries, the regulator itself who operate in their interest rather than the industry they regulate, unions, and the myriad of self interest groups within the industry itself, all creating cacophonous political noise that overwhelms the political classes ability to see the wood from the tree's.
This has allowed the regulator and its stable mates and minions to subtly position themselves outside the law, empower themselves to the point where they can even dismiss a minister who attempts to rein them in and open a conduit for their more senior managers to avail themselves to the trough of soft corruption.

The current arguments over what is "legal", what is not, what is "legal", against what is common sense, what is "legal" what makes no sense, all illustrates the confusion that exists within our Industry caused by regulatory malfeasance.

In 2009 Robin speed wrote a warning article "The rise and rise of the regulator".
It is sobering to realise just how right he was.

FGD135
14th Apr 2017, 04:36
This is not a problem for GA. This is CASA's problem.

There is no rule that says a pilot has to KNOW exactly what his takeoff distance will be. There is also no rule that says he has to DETERMINE his takeoff distance prior to taking off (or how he must determine it).

Sure, there is a great big rule that says he must not take off overloaded, but to satisfy this rule does not necessarily require him to know what the takeoff distance will be.

So, most people will then say, "but how does he know that he has sufficient runway if he does not, or cannot, consult a chart?".

And the answer to that question can be something like, "I know from experience that I have sufficient runway." He could even say that he has consulted the local clairvoyant, or done a reading of his tea leaves.

The point is that it would be up to CASA to prove that he did not have sufficient distance available when he commenced the take off roll. This is where it becomes CASA's problem.

djpil
14th Apr 2017, 04:53
my approach would be to use a higher altitude/lower temperature giving the same density altitude and enter the chart that way.

On what basis ? Not being wary of extrapolating to higher elevations and OATs might present problems. Things aren't necessarily linear.

For the typical non-engineering pilot, I would suggest don't extrapolate high. If the elevation/temperature is lower than the the chart data, and there are no other systems limitations prescribed in the limitations section, maybe .. and, in that case, use the published data without trying to take advantage of extrapolation.Yes indeed. Years ago, I had an old model 172 at 6500 ft pressure altitude and 85 deg F. I spent a lot of time cogitating on the takeoff distance and, especially, the climb performance. I had enough information in the manual to indicate that it would be OK but it would not have achieved CASA's requirement for 6% gradient. This was in another country with no such requirement.

I would be interested in djpil and JT comments.

I think Dave and I would opine along the lines that we would, .... reschedule the performance data .. get a tick in the box .. and Robert's your parent's sibling.Yes indeed. American AFM's were not intended to specifically provide the data required to determine takeoff weight etc per CAO 20.7.4. So, if one cannot determine the weight at which both runway distance is adequate and climb gradient is 6% then you shouldn't go.

Of course, Kaz can use trial and error in the Auster to determine it.

megan
14th Apr 2017, 06:11
With respect to your last para JT the Cessna 206 manual data for take off and landing are given only for using the stipulated short field techniques and using a paved, level, dry runway. No figures for water soaked dirt bush strips, that also may have grass coverage, or standing water. And you are not going to use the proscribed short field take off procedure on a gravel strip due prop erosion/damage (full power prior to brake release), data for the 404 take off is also full power prior to brake release.

So how do we approach that if chart data is the Holy Grail? Only operate on paved, level, dry runways using short field techniques? I note djpil,if one cannot determine the weight at which both runway distance is adequate and climb gradient is 6% then you shouldn't go.which hints, to me at least, that since I can't adequately determine the runway length necessary for bush strip operations I must confine myself to a paved, level, dry runway. This despite the manual in normal procedures talking about gravel and soft field operations.

All the Cessna manuals I've seen have a preamble to the performance section which says,Demonstrated Operating Temperature
Satisfactory engine cooling has been demonstrated for this airplane with an outside air temperature 23°C above standard. This is not to be considered as a operating limitation. Reference should be made to Section 2 for engine operating limitations.My interpretation of that is there is no OAT limit, if there were surely it would be in the limitations section, as some aircraft have.

kaz3g
14th Apr 2017, 07:21
......if one cannot determine the weight at which both runway distance is adequate and climb gradient is 6% then you shouldn't go.

Of course, Kaz can use trial and error in the Auster to determine it.

Thank goodness I crash so slowly!

And I think it's your turn to buy the red after that :p

Kaz

Ps. There is a flyin to Ian Dickson's and Jenny Houghton's on Anzac Day.

djpil
14th Apr 2017, 07:46
All the Cessna manuals I've seen have a preamble to the performance section which says,My interpretation of that is there is no OAT limit, if there were surely it would be in the limitations section, as some aircraft have.Agreed, limits per FAR 23.1583 go in the limitations section of the AFM.
Per FAR 23.1587, the range of parameters required for the performance charts/tables are specified in FAR 23.45 - airport altitudes SL to 10,000 ft; temperatures from std to std + 30 deg C. Nothing in the certification or operating rules of the country of origin to suggest that the extremes of those ranges are the limits.

Earlier versions of FAR 23 required the information from SL to 8,000 ft and temperatures from 60 degrees F. below standard to 40 degrees F. above standard. An even earlier version of FAR 23 (applicable to my airplane) did not require AFMs for small airplanes to provide any such performance information.

In this discussion I use a PA28-161 AFM as my example (and some of my comments apply specifically to single pistons below 6,000 lb), relevant statements in its AFM:
"Performance information derived by extrapolation beyond the limits shown on the charts should not be used for flight planning purposes."
It only has data for a paved level runway however it has this statement: “Effects of conditions not considered on the charts must be evaluated by the pilot, such as the effect of soft or grass runway surface …”. CASA's Flight Safety magazine had an article a while back about how to deal with it - from memory, that article was based on https://publicapps.caa.co.uk/docs/33/20130121SSL07.pdf

There is a flyin to Ian Dickson's and Jenny Houghton's on Anzac Day.I'll check all of the performance info for my airplane and see if it is OK per CAO 20.7.4 for me to go - subject to the prop shop returning the delicate MT.

john_tullamarine
14th Apr 2017, 10:17
Our regulator is hell bent on wiping out all forms of aviation beyond RPT or the military, who by their size, political power and financial resources are somewhat immune to the imposts of overregulation. For nefarious reasons we stakeholders at the bottom of the pile could never comprehend.

Oh, OK. I thought the previous CASA related comments just suggested that CASA's concern was more along the lines of "be careful out there, chaps ..".

There is no rule that says a pilot has to KNOW exactly what his takeoff distance will be. There is also no rule that says he has to DETERMINE his takeoff distance prior to taking off (or how he must determine it).

I shan't go into laboured discourse .. however, I wouldn't like to go to Court and defend whatever on the basis of your argument ...

So how do we approach that if chart data is the Holy Grail?

One of the problems (as alluded to by djpil) is that the local operational rules (20.7) were set up on the basis of now defunct local certification rules (101.xx). The US rules are a tad different in philosophy and the two don't quite mix comfortably.

On the other hand, one could consult with one's Industry Consultants (at modest expense) to sort out the problem on a specific Type basis. Seriously, though, Ron (rest his good soul) has a few things to answer for ..

Thank goodness I crash so slowly

Thanks be to the US regulator of olde who, with finger in the wind, pontificated that SE stall ought not to exceed 70 mph (61 kt for those who subscribe to that dreadful metrication stuff) on the basis that it seemed to make good sense.


At day's end, there are two important rules ..

(a) Rule 1. Don't crash

(b) Rule 2. Have a good story which will hold up in Court in the face of spirited and enthusiastic seeking of the dollar from your pocket ..

If you are able to observe Rules 1 and 2, the rest is amenable to discussion over a hot coffee.

kaz3g
14th Apr 2017, 10:55
John, the AUSTER Stalls at 26 knots and I was joking

Kaz

FGD135
14th Apr 2017, 13:37
I shan't go into laboured discourse .. however, I wouldn't like to go to Court and defend whatever on the basis of your argument ...Courts are about laws. There is only one law in this case:

Thou shalt not take off overloaded.

But if you took off with the temperature at 41, when your charts only went to 40 degrees, how are they going to prove that you took off overloaded? They can't use the charts because they are not valid.

john_tullamarine
14th Apr 2017, 14:39
John, the AUSTER Stalls at 26 knots and I was joking

Noted .. a long time since I enjoyed an Auster ... my thoughts are more to the new folks who might be watching the thread .. just part of how I play in the sandpit.

how are they going to prove that you took off overloaded?

The concern is more .. how are you going to prove your operation was in compliance with the regulatory bits and pieces ? A goodly chance of being hung, drawn and quartered I suggest ..

FGD135
14th Apr 2017, 14:44
.. how are you going to prove your operation was in compliance with the regulatory bits and pieces ?It is they that have to prove it. It is they, bringing the case, after all.

Bankstown Boy
14th Apr 2017, 23:35
It is they that have to prove it. It is they, bringing the case, after all.

No offence intended to you FGD135, but the quaint notion that the courts have some sort of "innocent until proven guilty" basis, is nothing more than wishful thinking.

Even in criminal matters that basis often no longer exists but it does not exist in civil matters at all.

Most law these days is written in strict liability prose and the "safer skies" mob are experts in this black art (everyone has to be good at something)

Simply put, even though they bring the action, you must prove your innocence/compliance.

FGD135
15th Apr 2017, 04:25
No offence intended to you FGD135, but the quaint notion that the courts have some sort of "innocent until proven guilty" basis, is nothing more than wishful thinking.
Bankstown Boy,

You are way off the mark. You seem to be saying that CASA can drag you to court because they THINK you have done something wrong, and you then have to prove otherwise.

That is ridiculous. Have a look at this:

Importantly, however, strict liability does not reverse the burden of proof, and there are no provisions in any CASA legislation (current or proposed) that do so. ‘Every element of a strict liability offence must be proven by the prosecutor, and proven beyond a reasonable doubt. It is not and has never been the case that the defendant must prove that they did not commit the offence.’

That quote was taken from this document:

Strictly liable, fairly enforced | Flight Safety Australia (http://www.flightsafetyaustralia.com/2015/09/strictly-liable-fairly-enforced/)


But of course, if you have gone off the end of the runway, and this is the reason you are in court, then the proof is self-evident and it will be nigh on impossible for you to prove otherwise! All of this just illustrates the simple point that JT made:

(a) Rule 1. Don't crash

megan
15th Apr 2017, 07:28
You are way off the mark. You seem to be saying that CASA can drag you to court because they THINK you have done something wrong, and you then have to prove otherwise.

That is ridiculous.I would think otherwise. Ask John Quadrio, AAT rejected the CASA case, but he never got his licence back. Imposition of strict liability is a departure from a fundamental protection of the criminal law. Strict liability may be justified where it is difficult to prosecute fault provisions, to overcome ‘knowledge of law’ issues, where a physical element incorporates a reference to a legislative provision, where it is necessary to protect the general revenue, or to ensure the integrity of a regulatory regime. Which is quite at odds with the thrust of Dr Jonathan Aleck's article. Since he is a CASA employee it's just a puff piece.

Bankstown Boy
15th Apr 2017, 07:53
My take on it all?

There are those that believe in the courts and the judicial system

And

There are those who have experienced the courts and the judicial system

From my substantial personal and professional experience, I remain convinced that these two groups are mutually exclusive.

FGD135, I mean you no harm nor insult but if it is your believe that an article by a CASA employee will protect you, then nothing I can say or do will sway your mind.

To put the sword to Aleck's aericle, most of our new and 'improved' legislation is written along the lines of (and this is paraphrasing)

A person in control of an aircraft [doing the thing] commits an offence, unless they [add numerous relevant defences]

An offence of section [] is of strict liability
Penalty units []


The way that rule is written, the way the regulator will prosecute it, and the way the court will enforce it, is - if you did [the thing] then you are guilty, unless you can prove you did [the relevant defence]

Sadly, that's the real world.

Even sadder, many of those "things" don't involve extremes like crashing and stuff, they are everyday activities.

kaz3g
15th Apr 2017, 10:25
In the criminal jurisdiction, the prosecution does not have to prove your intention to do the act but it does have to prove each of the elements of the offence beyond reasonable doubt.

The standard of proof in civil matters is on the balance of probabilities...ie more likely than not.

Kaz

Lead Balloon
15th Apr 2017, 10:42
Every element of a strict liability offence must be proven by the prosecutor, and proven beyond a reasonable doubt.And most strict liability offences in the civil aviation law have a grand total of one element.

Prosecution is usually the least of your worries. If you're not a complete recidivist you're likely to end up with a discharge without conviction, years after the event.

Administrative decisions are a far more efficient weapon of torture - sorry - safety tool.

Squawk7700
15th Apr 2017, 11:09
And most strict liability offences in the civil aviation law have a grand total of one element.

Touché!

I'm sure many don't realise this....

For the offence of low flying, you only need to have been caught low flying... that's 1 point of proof. For "theft," there are a number of proof points, including your Actus Reus and Mens Rea, not to mention your intention to permanently deprive.

It's far more simple to pin someone for an aviation offence due to strict liability. It's a thread and a half of discussion on its own.

kaz3g
15th Apr 2017, 12:17
Touché!

I'm sure many don't realise this....

For the offence of low flying, you only need to have been caught low flying... that's 1 point of proof. For "theft," there are a number of proof points, including your Actus Reus and Mens Rea, not to mention your intention to permanently deprive.

It's far more simple to pin someone for an aviation offence due to strict liability. It's a thread and a half of discussion on its own.

"low" and "flying" are at least two points of proof and implicitly suggest several more.

Kaz

Lead Balloon
15th Apr 2017, 12:47
(4) The pilot in command of an aircraft must not allow the aircraft to take off if its gross weight exceeds its maximum take‑off weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the take‑off, that lesser weight.

Penalty: 50 penalty units.

(5) The pilot in command of an aircraft must not allow the aircraft to take off if its gross weight exceeds, by more than the weight of fuel that would normally be used in flying to its next landing place or planned alternative aerodrome, its maximum landing weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the landing at that place or aerodrome, that lesser weight.

Penalty: 50 penalty units.

(6) The pilot in command of an aircraft, must not land the aircraft if its gross weight exceeds its maximum landing weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the landing, that lesser weight.

Penalty: 50 penalty units.

(7) CASA may, for the purpose of ensuring the safety of air navigation, give directions with respect to the method of loading of persons and goods (including fuel) on aircraft.

(7A) A person must not contravene a direction under subregulation (7).

Penalty: 50 penalty units.

(8) The pilot in command of an aircraft must not allow the aircraft to take off or land if a direction given under this regulation, about the loading of the aircraft has not been complied with.

Penalty: 50 penalty units.

(9) The pilot in command must ensure that the load of an aircraft throughout a flight shall be so distributed that the centre of gravity of the aircraft falls within the limitations specified in its certificate of airworthiness or its flight manual.

Penalty: 50 penalty units.

(10) A direction given under this regulation does not have effect in relation to a person until it has been served on the person.

(12) An offence against subregulation (2A), (4), (5), (6), (7A), (8) or (9) is an offence of strict liability.

Note: For strict liability, see section 6.1 of the Criminal Code.

(13) It is a defence to a prosecution under subregulation (6) if the landing was made in an emergency.

Note: A defendant bears an evidential burden in relation to the matter in subregulation (13) (see subsection 13.3(3) of the Criminal Code).Simple. :ok:

FGD135
15th Apr 2017, 13:13
The way that rule is written, the way the regulator will prosecute it, and the way the court will enforce it, is - if you did [the thing] then you are guilty, unless you can prove you did [the relevant defence]

Sadly, that's the real world.
Bankstown Boy,

I believe you are getting a few things confused. If CASA are dragging you to court, then they will *already* have the proof and therefore, a high confidence the conviction will succeed.

There is no way they would take you to court with less. You seem to be saying they would take you to court with just an allegation.

Once in court, you can defend yourself. Is it this stage where you believe you are under the assumption that you are "guilty until proven innocent", and thus have to now prove you are innocent?

Lead Balloon
15th Apr 2017, 13:23
It's the CDPP that "takes you to court" to prosecute you, not CASA.

Unfortunately for the hapless defendant, the CDPP is usually initially enthralled by the mystique of aviation safety. Fortunately for the hapless defendant these prosecutions usually lead nowhere, unless you happen to be someone who's carried dangerous goods on an RPT aircraft..

Derfred
15th Apr 2017, 20:14
I find it interesting to compare "strict liability" to how sharia law is implemented in some countries.

Such as, (to paraphrase according to CASA): "A woman must not engage in sexual activity outside of marriage. This is a clause of strict liability".

So if a woman is raped, and confesses, under strict liability she is guilty of the offence. Intent does not come into it. She is automatically guilty. All she can hope for now is empathy from the courts, she has no "legal" defense.

That's "strict liability" for you.

To put it back on topic, if you take off at 42C (and you know it's safe because whatever), but it's outside of your charts, and you encounter unpredictable windshear on departure that causes an accident, where is the burden of proof that you caused the accident?

CASA could claim the temperature caused the accident. Yes the burden of proof is on CASA that you took of at 42C, but that would be easy to prove, and as it's a clause of strict liability you are now liable. The burden of proof of the windshear is now on you. So yes, you are now guilty unless you can prove yourself innocent, which may not be easy.

Disclaimer: not a lawyer. And yes LB, of course the DPP takes on all prosecutions, as always, but they do so on behalf of CASA, using CASA's evidence, CASA's regs and CASA's desire to prosecute.

thorn bird
15th Apr 2017, 21:21
All these arguments lead me to the conclusion that whoever wrote

"The law is for everyone, justice is for them that can afford it"

Is profoundly correct.

If CAsA was in any way a "Model Litigant" and in many cases as we have seen
from bitter experience a "Moral Litigant" perhaps that statement would be less poignant.

Horatio Leafblower
16th Apr 2017, 02:23
Kaz

In the criminal jurisdiction, the prosecution does not have to prove your intention to do the act

Quite wrong. normal criminal law requires both a criminal act and a criminal mind - acrus reus and mens rea - not only the doing of the thing but an intention to do so.

In a world full of administrative rules, very few of us intend to break the law. That's why they make the rules strict liability.

FGD135
16th Apr 2017, 03:18
Yes the burden of proof is on CASA that you took of at 42C, but that would be easy to prove, and as it's a clause of strict liability you are now liable.
Easy to prove?

There is no law that says you can't take off at 42C. The only applicable law says you can't take off overloaded.

But how can CASA prove you were overloaded when the charts only go up to 40C?

Bankstown Boy
16th Apr 2017, 03:42
But how can CASA prove you were overloaded when the charts only go up to 40C?

FGD135, there is no requirement for the Prosecutor (which is not CASA) to prove you were overweight. It is up you to prove that you were not.

The law clearly (albeit in my opinion, stupidly) states that you must not allow the aircraft to takeoff overweight.

If the charts cannot be extrapolated and you are operating outside of a limit of that chart, then you are breaking the law. The law is one of strict liability that permits no defence.

Sadly there is nothing to stop CASA ramp checking anyone who commits aviation on a +40C + SL day and asking how you complied with the strict requirement. The short answer is you can't and they could, if they wished, send you the 'fax' and refer to the prosecutor.

FGD135
16th Apr 2017, 03:49
It is up you to prove that you were not.So you're guilty until proven innocent under Australian law, then?

... and you are operating outside of a limit of that chart, then you are breaking the law.Ok, so which law is that?

The short answer is you can'tActually, there are ways, involving your experience. For example, you could say, "I took off perfectly safely yesterday, under the exact same conditions". Note that the law doesn't stipulate how you have to assess your takeoff performance.

Flying Binghi
16th Apr 2017, 04:14
via Bankstown Boy:
...Sadly there is nothing to stop CASA ramp checking anyone who commits aviation on a +40C + SL day and asking how you complied with the strict requirement. The short answer is you can't and they could, if they wished, send you the 'fax' and refer to the prosecutor.

And that gets us back to just how were the temperature defined for the ramp check ? ...the 'official' met which is not a now figure, or from the 'ambient' temperature taken somewhere near the aircraft at a particular time.
On a hot summers day if the aircraft is parked between a row of stifling windless hangers the temperature at the aircraft could be anywhere up to 10+ degrees hotter then if it were parked 50 metres away on the wind swept grass near, though not under, that shady tree. There is no fixed ambient temperature on an airfield.

The other mater is many of the temp charts for older aircraft were done before electronic temperature recorders were in common usage. Older temp gauges are a bit lazy, i.e. They only give an average temperature over a few minutes time frame and thus do not record every fleeting high temperature peak like the electronic temp gauges do. This is well seen with the current global warming idiocy where modern temperature 'records' recorded on millisecond recording electronic equipment is compared to the older temperature records recorded via lazy mercury gauges. It may be something CASA needs to look at as to how a pilot defines the temp to use.

I suspect even Rumpole could run rings around any ramp check temperatures if it were bought to court. At any rate, it would certainly put CASA square into the global warming 'issue'..:cool:







.

megan
16th Apr 2017, 04:27
Note that the law doesn't stipulate how you have to assess your takeoff performanceAnd you can't if you're not taking off from the paved, level, dry runway typically specified on the chart.

djpil in an earlier post provided information on how to factor the take off distance for runways that were not as described on the chart, but I'm not aware of any OFFICIAL document giving our newly minted 172 PPL guidance, or anybody else for that matter.

In a previous life used to operate out of wheat paddocks with standing stubble. Sure extends the run.

FB, you raise a good point about temperature. In summer the aircraft gauge could get up to 60C from heat soak if it had been standing for a period of time. No other source of info. Prop wash after start used to bring it back.

Bankstown Boy
16th Apr 2017, 04:55
So you're guilty until proven innocent under Australian law, then?

Yes. for strict liability civil matters, yes. It's been that way for some time.

Ok, so which law is that?

the bit that says "you must". the law says nothing about interpreting the chart, or what happens if you "draw" outside the lines. It simply says that you must do a thing, and you have been left with no way to prove that you did that thing. Ergo, you have committed the offence.

For example, you could say, "I took off perfectly safely yesterday, under the exact same conditions".

No you could not, you would simply be admitting to breaking the law twice on successive days. That's beginning to look like systemic failure to CASA. You could also say that you took off 500kg over MGTOW yesterday and it was fine, so there is no issue with the MGTOW rule either; or I flew without a valid medical and it was fine too.

The law doesn't work the way you think it does. If you tried anything that you have suggested as your version of a defence, then after counsel for the prosecution stopped sniggering the magistrate or judge would pretty much move to the penalty phase.

You are labouring under the misapprehension that there is an innocent until proven guilty clause in Australian civil law. There is not.

Bankstown Boy
16th Apr 2017, 05:01
And that gets us back to just how were the temperature defined for the ramp check ?
.

Cannot disagree with you but if it's 48C on the AWIS and the TAF and on the BOM's "you-beaut" historical temperature data recording, you're just not gunna get away with "but my temperate gauge read 39C, your honour"

You would need some basis for making the claim and owning up to the fact your temperature gauge is inaccurate ... well the 'safer skies' mob have strict liability rules on accuracy of gauges too.

OZBUSDRIVER
16th Apr 2017, 05:37
The most modern aircraft I have an AFM is the C208. In limitations it says-

OUTSIDE AIR TEMPERATURE LIMITS
Cold Day: ·· -54°C from sea level to 25,000 feet.
Hot Day:
Ground Operations: +53°C from sea level to 5000 feet; ISA +37°C above 5000 feet. . Flight Operations: ISA +35°C from sea level to 25,000 feet.

The aircraft I am endorsed to fly, The C182P AFM does not have a temp limit anywhere in limitations...it has a service ceiling of 17700ft

If I am at AS, elevation 1789Ft and a temp of 42C...my 182 could surely never leave the runway..yet it does...why is this so?

OK whats the density altitude? for 42C...if pressure alt is right for AS then the density alt is going to be 5500ft say 6000ft...go back to chart for takeoff at max weight..look for ISA temp, not there so go to 20C graph and 6000ft
which gives you your takeoff performance...if someone is so bloody dumb not to understand how to use their P charts they do not deserve to hold their licence...ANY LICENCE!

So..if the there is no temp limit written in limitations there is NO LIMIT FOR TEMPERATURE!

Last time I passed PPL my wing sees only air density, my internal combustion engine only sees air density. The charts are there to help the pilot make interpretations easier. Just because the company calculations stop at 40C does not mean that is a limitation. If there is a pressure altitude up to 8000ft that means you have density altitude to 8000ft USE IT! and tell CASA where to bloody go if they ever try this on you!

OZBUSDRIVER
16th Apr 2017, 06:07
Effectively, the Cessna charts give you pressure altitude up to 8000ft at max weight. ISA at 8000ft is 0C. So my C182 p chart runs out at a pressure alt of 10500ft for max weight. If I lower my weight I can get p charts to
ISA+40 or 13000ft pressure altitude. I have never operated in PNG or West Irian but I am pretty damn sure any pilot who has flew up there can tell me that a C182 can take off from 8000ft pretty well.

FGD135
16th Apr 2017, 06:19
Bankstown Boy,

It is tough to debate you when you don't answer my questions and fail to understand what I have written. I am going to have to go over everything again, laboriously. Please read carefully this time, and answer my questions.

Can you give an example of a "strict liability civil matter" where you are presumed guilty until proven innocent? If what you are claiming is true, then you could be taken to court on nothing more than an allegation - and then convicted if you fail to mount a defence.

Are you saying that this happens in Australia? Can you give an example?

Take the case of a cop issuing you with a speeding infringement. This would be an offence of strict liability in every state. Do you consider this to be an example of a case where you are "guilty until proven innocent"? Please answer this question.

When I asked "Ok, so which law is that?", I was actually referring to this statement of yours ...

If the charts cannot be extrapolated and you are operating outside of a limit of that chart, then you are breaking the law.
... and asking which law it is that you have broken. There is no law that says you must not operate outside the limits of a chart. Can you point me to any such law?

You could also say that you took off 500kg over MGTOW yesterday and it was fine, so there is no issue with the MGTOW rule either; or I flew without a valid medical and it was fine too.This statement shows, very clearly, that you do not understand what I have written. I have never said, nor implied, any such thing. My whole point is that to break a law, the law has to exist in the first place. There are clear laws that apply to takeoff weight and medical certificates.

When it comes to taking off, there is only one law, and it states that you cannot take off overloaded. Therefore, to charge you under this law, the allegation has to be that you "took off overloaded". It cannot be that you went outside a chart limit.

By admitting that you "took off yesterday under identical conditions", what law have you broken?

Let's say you safely took off at 42C, but your charts only went to 40C. Are you saying CASA could charge you with an offence? If so, then please state exactly which law it is that you have broken.

Band a Lot
16th Apr 2017, 07:01
Queensland landholders 'guilty until proven innocent' under land clearing reforms - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2016-06-03/queensland-land-clearing-reforms-likened-to-vlad-laws/7475548)


One example is section 685 of the Local Government Act. It reverses the presumption of innocence by making that mere allegations, such as that someone has not received a council approval, is "sufficient proof of the matter" alleged. In the words of the chief justice, this "renders someone guilty of a criminal offence by a mere accusation".


Another example is section 60E of the Water Management Act. It says that where water is taken without a licence, the occupier of the relevant premises is deemed guilty of an offence. Remarkably, the act goes on to state that this does not prevent proceedings being brought against "the person who actually committed the offence".


Federal law provides many further examples. A long list is set out in the report on traditional rights and freedoms released earlier this month by the Australian Law Reform Commission. Some of the federal laws that breach the presumption are in expected areas such as terrorism and drug offences. Others relate to taxation, copyright and marriage.

Bankstown Boy
16th Apr 2017, 07:14
Bankstown Boy,

It is tough to debate you when you don't answer my questions and fail to understand what I have written. I am going to have to go over everything again, laboriously. Please read carefully this time, and answer my questions.



FGD135, I don't know what school of self-entitlement you went to, but demanding that I read carefully and then answer your questions, is surely a some form of a joke?

I don't owe you a living and I am not your servant.

This is a forum where people come to discuss things.

I have answered your questions explicitly and in some detail previously. The fact they do not accord with your world view, nor do you feel that I have answered you to your satisfaction in no concern of mine.

I suggest if you have any interest, go back and read the succinct answers I gave to your questions, or don't, as suits you. I don't particularly care either way.

Happy Easter, or may the bunny have been good to you, depending on your personal proclivities.

Icarus2001
16th Apr 2017, 07:30
If CASA cannot prosecute a Qantas crew for taking off with no runway lighting in Hobart, what chance have they got in your hypothetical situation of high temperature?

This stuff is only a problem if you have an accident as there is a financial imperative from the insurance company to show that you did something wrong.

Accused Qantas pilots won't stand trial (http://www.news.com.au/national/accused-qantas-pilots-wont-stand-trial/news-story/a856f58b66f9bb9c3690a3b7ba57c171)

djpil
16th Apr 2017, 09:07
djpil in an earlier post provided information on how to factor the take off distance for runways that were not as described on the chart, but I'm not aware of any OFFICIAL document giving our newly minted 172 PPL guidance, or anybody else for that matter.Seems that it has fallen in a hole. CAO 20.7.4 is very specific that short dry grass must be used to determine takeoff distance. Student pilots practice short field operations at grass strips and they get to calculate the relevant distances before they launch off on a nav exercise.
I've seen one big flying school use a modified version of CASA's SE Endorsement Questionnaire to specify short dry grass for the airfield performance question.

john_tullamarine
16th Apr 2017, 14:12
There is no law that says you must not operate outside the limits of a chart. Can you point me to any such law ?

Now, I'm just an average old pharte pilot and aero engineer, not a lawyer in any sense of the word.

However,

(a) the Act [98 (3)] talks about the Governor General's having the power to make regulations for or in relation to the following

(b) [(h)] goes on to say empowering CASA .. to give or issue directions or instructions ... with respect to matters affecting the ... operation ... of aircraft

(c) [(ka)] provides for requiring the production/amendment of flight (and other) manuals

(d) [(kd)] talks about requiring specified persons to comply with such manuals, systems and documents as in force at a particular time or from time to time

(e) CAR (1988) 2 gives some pertinent definitions -

gross weight, in relation to an aircraft at any time, means the weight of the aircraft, together with the weight of all persons and goods (including fuel) on board the aircraft, at that time, estimated in accordance with the method set out in a direction in force under subregulation 235(1).

maximum landing weight, in relation to an aircraft, means the weight set out in the certificate of airworthiness of, or the flight manual for, the aircraft as the maximum landing weight.

maximum take‑off weight, in relation to an aircraft, means the weight set out in the certificate of airworthiness of, or the flight manual for, the aircraft as the maximum take‑off weight.

It follows that the AFM regulated weights would be captured as well as the TC weights - see CAR (1988) 235.

(f) CAR (1988) 54 talks more about flight manuals

The registered operator of an aircraft must ensure that the aircraft’s flight manual is at all times appropriate for the aircraft, having regard to:
(a) any direction issued by CASA relating to the flight manual; and
(b) any modifications to the aircraft that would require amendment of the flight manual; and
(c) any instructions in relation to the flight manual from the holder of a type certificate, supplemental type certificate or modification/repair design approval that applies to the aircraft

(g) CAR 233 (b) has this to say -

the gross weight of the aircraft does not exceed the limitations fixed by or under regulation 235 and is such that flight performance in accordance with the standards specified by CASA for the type of operation to be undertaken is possible under the prevailing conditions

(h) CAR 233 (c) adds this -

any directions of CASA with respect to the loading of the aircraft given under regulation 235 have been complied with

(i) CAR 235 is the catch all, I think ..

(1) CASA may, for the purposes of these Regulations, give directions setting out the method of estimating, with respect to an aircraft at anytime:
(a) the weight of the aircraft, together with the weight of all persons and goods (including fuel) on board the aircraft, at that time ...
(2) CASA may ... give directions setting out the manner of determining, with respect to a proposed flight of an aircraft:
(a) a maximum weight, being a weight less than the maximum take‑off weight of the aircraft; or
(b) a maximum weight, being a weight less than the maximum landing weight of the aircraft;
that the gross weight of the aircraft at take‑off or landing, as the case may be, is not to exceed.
(2A) A person must not contravene a direction under subregulation (1) or (2) ...

(3) A manner of determining a maximum weight referred to in subregulation (2) shall be such as to take into account such of the following considerations as CASA considers appropriate:
......
(d) the meteorological conditions at the aerodrome at which the aircraft is to take off or land;
(e) the altitude of the aerodrome at which the aircraft is to take off or land;
.....
(g) the material of which the surface of the aerodrome in the direction in which the aircraft is to take off or land is constituted and the condition and slope of that surface
......
(4) The pilot in command of an aircraft must not allow the aircraft to take off if its gross weight exceeds its maximum take‑off weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the take‑off, that lesser weight.
.....
(6) The pilot in command of an aircraft, must not land the aircraft if its gross weight exceeds its maximum landing weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the landing, that lesser weight.

Presuming that the typical pilot is, indeed, familiar with the CAO 20.7 series, one should have a look at the following CAOs which cover the bulk of operations ...

(j) CAO 20.7.1b which talks about elevations and ambient temperatures

(k) CAO 20.7.4 which talks about pressure heights and temperatures.


I think you should be planning on co-opting the services of very good Counsel in the event that you are challenged in Court regarding your philosophies ...

Skillsy
16th Apr 2017, 15:41
I can see Denis Denuto prosecuting for CASA... "No, it's just the vibe, I rest my case". Can anyone help with how many rotary and smaller fixed wing fire fighting aircraft will this possibly cover for SE Australia?

Aussie Bob
16th Apr 2017, 23:18
Last time I passed PPL my wing sees only air density, my internal combustion engine only sees air density. The charts are there to help the pilot make interpretations easier. Just because the company calculations stop at 40C does not mean that is a limitation. If there is a pressure altitude up to 8000ft that means you have density altitude to 8000ft USE IT! and tell CASA where to bloody go if they ever try this on you!Among a sea of bush lawyers (and a couple of real ones) at least someone is on the ball and knows their stuff.

holdingagain
16th Apr 2017, 23:27
I might of missed this bit, if they are going to take you on where is the 40+ degrees sourced from, the aircraft probe, TAF, ATIS ect.

john_tullamarine
16th Apr 2017, 23:33
if they are going to take you on where is the 40+ degrees sourced from

This is the saving grace with temperature .. the local rules permit a variety of not so precise accuracy temperatures so it would be reasonable to presume a range of arguments could be presented to cover the situation.

The important thing is that one needs to be very careful and, perhaps, a bit conservative, if one wishes to step a little outside the charts in respect of any of the variables. I don't think a degree or two in OAT will overly excite CASA but that is just the thin edge of the wedge, as it were.

Sunfish
17th Apr 2017, 00:13
The problem with CASA, as demonstrated by this debate, is that they rely on legal arguments which by definition, have nothing to do with safety, in fact the legal arguments are anti safety.

Hence Djplls observation that as his Decathlon has no performance charts, he can do what he likes in respect of temperature with no possibility of CASA prosecution.

In other words, the absence of information on the performance degradation at high density altitudes in the documentation is a net positive from the point of view of avoiding prosecution. This is the reverse of a safety culture.

I have noticed this before in the way aviation is regulated, for example, my aircraft, if it is ever finished, needs an environmental noise compliance certificate ...which will state that this aircraft is exempt from the requirement to have a compliance certificate!

From the point of view of creating a safety culture, it appears to me that CASAs approach is counterproductive. For example, I now know enough to ensure that I will never fit a camera or post stuff to youtube. Data logging is going to be disabled, the maintenance manuals and POH I need to produce will be the bare minimum skeletons I can get away with and any aviation activities will be conducted as far from prying eyes as possible. The aircraft will never fly to shows or events which attract CASA ramp checkers.

Basically CASA has so prescribed aviation activities in this country as to almost make it not worth it.

jonkster
17th Apr 2017, 00:26
I think people keep ignoring what a couple of posters have said, POH take-off charts typically provide pressure altitudes and temps however there is nothing to stop the pilot working out an equivalent density altitude and using that instead. It is just a convenience to help calculate, not a performance limitation.

If you had a density altitude that exceeded the values covered by the TO chart/table then maybe rethinking the take-off would actually be sensible. The only manual I have to hand at the moment has TO figures for a PA up to 8000' and temps up to 38C

This would mean you have a chart that covers density altitudes to over 12,000' (!)

eg
50C at Oodnadatta would have a DA I think a bit over 4000'

If you had 50C OATat Oodnadatta, although it isn't listed in the table, you pick the 4000' DA point (4000' and 7C) and you can calculate the TO distance just fine using that value. You are well within the calculated performance values even if 50C is not listed.

I seriously doubt there would be many times in Oz where a strip would ever exceed a 12,000' DA - and if there was - rethinking a takeoff in those conditions would make serious sense.

PPLs are required to understand and calculate density altitude as part of their theory course.

Bankstown Boy
17th Apr 2017, 01:04
Jonkster, there is no doubt, to me, or I suspect any trained pilot that the aircraft only cares about density altitude and that any (I've seen) p charts easily allow you calculate said density altitude.

But we are discussing the law, not aviation.

The law doesn't operate in the same way science (or mostly commonsense) does.

To a pilot, PA+OAT=DA (simplified) and therefore you and I could use the same p chart, at the same airport, in the same conditions, and come to same conclusion about rwy length/TOW. It's repeatable and falsifiable, ergo science.

To a barrister (and almost universally to a court) the p chart has temperature and pressure lines and you can't extrapolate.

If you were wealthy (hired a good team of an SC, a junior, and had good instructing solicitors) and you were lucky on the day; you might convince the court that what you say is actually correct.

But the wealth of evidence is against you. The relevant evidence acts are probably the most arcane part of our legal system, you think aviation law is turgid and dense, it's got nothing of the rules surrounding evidence and admissibility. I would suspect that you would require evidence from an expert witness (physicist, or atmospheric scientist) to testify to the formula, otherwise it is simply hearsay and would be struck. That expert is only going to have been appointed after a few directions hearing and challenges and then you better hope they impress on the day, don't say anything stupid, like it's not actually 1.98C per 1,000 feet as that's an estimate/average (bye, bye your argument).

Sounds ridiculous? Stick to flying and mooning CASA, that's what I do, it's far simpler and easier on the blood pressure.

megan
17th Apr 2017, 03:04
CAO 20.7.4 is very specific that short dry grass must be used to determine takeoff distancedjpil, to quote6.2 For aeroplanes operated on land, take-off distances are to be determined for a level short dry grass surface.and6.3 Where there is an approved foreign flight manual or a manufacturer’s data manual for an aeroplane that sets out the take-off distance required for that aeroplane, then that aeroplane must be operated so as to comply with either the requirements set out in paragraphs 6.1 and 6.2 or the requirements relating to take-off distance set out in either of those manuals.There are no charts covering take off on short, dry grass so I'm obliged to comply with the highlighted portion of para 6.2. ie I can only operate from a paved, level, dry runway, since that is the only condition for which data is available.

Operate off anything else and run into the trees at the end the Feds are going to ask "how did you substantiate the take off performance? Please tender to the court the CASA approved chart".

So how does Farmer Fred go about operating his 182 to land and check his dams, bore pumps, troughs etc that CASA will accept as "legal", whatever that means? Paved, level, dry runways?

FGD135
17th Apr 2017, 03:29
Operate off anything else and run into the trees at the end the Feds are going to ask "how did you substantiate the take off performance?

This is what it really comes down to, and post after post has been skirting round this reality.

Here it is again:

Run off the end of the runway due lack of performance and CASA will come after you. The proof is self evident. Outside the charts or not, you have demonstrably taken off overweight.

or

Get safely airborne and CASA will not come after you. Sure, somebody may dob you in because he knows you were outside the performance envelope, but even in this case, CASA would think twice about whether it would be worth pursuing you.

djpil
17th Apr 2017, 06:15
Run off the end of the runway due lack of performance and CASA will come after you. The proof is self evident. Outside the charts or not, you have demonstrably taken off overweight.More likely used the wrong technique if the people that I see operating piston singles is any guide.

Well, I found that article about how to correct for the effect of short dry grass in the Sept-Oct 2002 issue of Flight Safety magazine and I was correct that the data came from the UK CAA.

The article was an analysis by “staff writers” about a takeoff accident to a Piper Lance PA-28R-300. My copy of the relevant POH has a chart to convert pressure altitude and temperature to density altitude then a takeoff distance chart presented vs density altitude only for a paved level runway. The authors focused on the importance of the correct technique per the POH and only at the end of the article did they note: “Additional factors should also be applied in the event that the performance chart does not make an allowance for variables like runway slope, runway surface, headwind component and so on (see table).” The table states a 20% increase in take-off distance for short dry grass.

Some other interesting statements in that article:
“….. It is tempting to simply say the whole episode could have been avoided if the pilot had consulted his aircraft’s take-off performance charts … However, it is unrealistic to assume that all light-aircraft pilots will calculate the exact take-off and landing distance required before every flight. ….… or the gap between the runway required and the runway available becomes marginal, the pilot refers to the performance charts and … How can we improve our decision-making skills? …….. A word of warning about aircraft performance charts. Depending on the year your aircraft was certified, its charts may or may not include built-in safety factors. ….. the production of uniquely Australian charts ceased and pilots …... calculate performance using information supplied by manufacturers. Aircraft manufacturers’ performance charts do not include built-in safety factors and in most cases reflect best-possible performance achieved with: Highly experienced test pilots …”

There was a time (two years ago) when we should’ve stopped worrying about CAO 20.7.4 – a note in the Exposure Draft of Part 91 (MOS for 91.1035 Aircraft Performance): “It is the intention that CAOs 20.7.4. …. will be subject of a project to review them and provide guidance material in the form of an AC in the future. Much of the content of the CAOs contain either certification standards or outdated information. CASA expects pilots to operate in accordance with the aircraft flight manual (AFM). All performance information in the AFM is produced and complies with the aeroplane certification standards.”

LeadSled
20th Apr 2017, 01:53
If CASA cannot prosecute a Qantas crew for taking off with no runway lighting in HobartFolks,
Perhaps because the analysis of the FDR, and the actual activation time base showed that the lights were on at the start of the takeoff roll, and the demonstrated probability was that they went off shortly after airborne. Remember the criminal standard of proof is "beyond a reasonable doubt".

Under cross examination, "eyewitnesses" are notoriously unreliable sources of evidence, as any criminal prosecutor knows.

Back to the thread, I haven't read the whole thread, has CAR 138 rated a mention? Then you have to understand the certification base for the particular aircraft AFM/POH, to understand what is an enforceable limitation and what is advisory in an AFM/POH (if the aircraft has one).

Tootle pip!!

andrewr
20th Apr 2017, 11:57
Funny you should mention CAR 138, since that is what CASA cite in their letter.

Their position is that the range of the parameters in the performance charts forms part of the limitations for the aircraft.

LeadSled
21st Apr 2017, 02:41
andrewr,
As I said, compliance with the AFM/POH/whatever presupposes you understand which parts of the AFM/POH are mandatory, and which are advisory, in the original certification. That can only be determined by understanding the original certification basis of the aircraft. For a US certified aircraft that is reasonably easy, not so elsewhere.

Make no mistake, the AFM/POH forms an essential part of the certification documentation of an aircraft, just as much as Continuing Airworthiness requirements, Weight and Balance etc., and is listed in the Type Certificate Data Sheet or equivalent.

That is not determined by CASA, or even properly understood by many on the CASA payroll, as evidenced by the continual demands for modifications to AFM/POH mandated procedures, without having the legal power, so to do. In my opinion, invariably increasing the risk (or “less safe”, if you insist on using that particularly useless term) to the operation, usually by intolerably increasing the flightdeck workload at critical phases of flight.

Not having the power doesn’t fazed the average enforcement minded CASA employee one little bit --- “they” well understand that “you” can’t afford a High Court case to prove them wrong.**

However, major airlines can afford said HCA case, and they do understand the limitation of CASA power to “order” AFM changes. ie: nil. All airlines of my experience are very careful to go through a comprehensive and legal process, if they want to modify, in ANY way, an AFM mandated procedure. They end up with a quite legal AFM that meets their needs.

The legal and reputational consequences to airlines, of not going through that procedure are to expensive to risk.

What is done is to negotiate any desired change with the Type Certificate holder and the state that issued the Type Certificate, only with the express approval of both is any operator’s change to an AFM “legal”. What said airline has, is an amended Type Certificate.

I suppose CASA could always raise a Legislative Instrument to mandate advisory sections of an AFM, but that would be very legally dodgy, if it was to be challenged.

All the above remarks specifically relates to the Australian legislative framework, not any other country.

Tootle pip!!

** CASA will "get" you some other way, if you do not obediently fall into line ---- like refusing to issue/reissue your AOC.

megan
22nd Apr 2017, 09:07
POH take-off charts typically provide pressure altitudes and temps however there is nothing to stop the pilot working out an equivalent density altitude and using that instead. It is just a convenience to help calculate, not a performance limitation.Agreed, as a read of the FAA Pilots Handbook dealing with take off performance centres on density altitude, which is as it should be, since that is what determines aircraft performance. In entering the graph or table with pressure altitude and OAT what you are determining is that at that (unstated on the chart) density altitude the take off run will occupy XXX feet. Of course you can determine the density altitude easily enough should you so wish, it's just that it's not stated on the chart. Density altitude is the only altitude your aircraft understands, it doesn't understand pressure altitude, nor temperature, as stand alone parameters.

https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/pilot_handbook.pdf

Extract from a Cessna 207 manual - at gross, short field on a paved, dry, level runway, distance to clear 50 feet, where I've calculated the DA from the formula DA = 1.24 PA + 118.8 OAT − 1782 and extended it to 50°C.

PA/OATXXx0°CXXX10°CXXX20°CXXX30°CXXX40°CXXX50°C
0XXXXXX-1782XXX-594XXXx594XXX1782XXX2970XXX4158 DA
XXXXXXXx1770XXx1900XXx2040XXX2195XXX2355XXXXXXXfDistance
1000XXXX-542XXXX646XXx1834XXX3022XXX4210XXX5398 DA
XXXxXXXX1940XXx2085XXx2240XXX2410XXx2600XXXXXXXfDistance
2000XXXXX698XXx1886 XXx3074XXX4262XXx5450XXX6638 DA
XXXXXXXx2130XXf2295XXX2470XXX2665XXx2875XXXXXXXfDistance
3000XXXX1938XXx3126XXX4314XXX5502XXx6690XXX7878 DA
XXXXXXxX2345XXf2530XXX2730XXX2955XXx3195XXXXXXXfDistance
4000XXXx3178XXx4366XXX5554XXX6742XXx7930XXX9118 DA
XXXXxxXX2595XXx2805XXx3035XXX3290XXx3570XXXXXXXXDistance
5000XxXX4418XXX5606XXx6794XXX7982XXx9170XX10358 DA
XXXXXxxx2880XXX3125XXx3390XXX3685XXx4020XXXXXxXXDistance
6000xxXX5658XXX6846XXx8034XXX9222XX10410XX11598 DA
XXXXxxXx3215XXx3495XXx3810XXX4165XXX4575XXXXXXXDistance
7000XXxX6898XXx8086XXx9274XX10462XX11650XX12838 DA
XXXXXxXx3615XXx3945XXf4325XXx4760XXXXXXXXXXXXXfDistance
8000XxXX8138XXx9326XX10514Xx11702XX12890XX14078 DA
XXXXxxXx4095XXx4500XXx4970XXXXXXXXXXXXXXXXXXXfDistance

A Koch Chart will similarly predict adjustments, based on OAT and PA, to be made for both take off and climb data.Their position is that the range of the parameters in the performance charts forms part of the limitations for the aircraft.And if look at the C207 data I've posted that limit is take off at a DA of 10,514 feet.

Icarus2001
22nd Apr 2017, 10:02
Folks,
Perhaps because the analysis of the FDR, and the actual activation time base showed that the lights were on at the start of the takeoff roll, and the demonstrated probability was that they went off shortly after airborne.

Or perhaps not. The evidence was LOST due to the passage of time.

What about this one?

https://www.atsb.gov.au/media/4128777/ao-2012-171_final.pdf

Here is some of the case info, I should have said Launceston but as there have been so many I confused them.

http://www.summarycrime.com/2009/05/losing-evidence-might-mean-losing-case.html (Folks, Perhaps because the analysis of the FDR, and the actual activation time base showed that the lights were on at the start of the takeoff roll, and the demonstrated probability was that they went off shortly after airborne.)

Capn Bloggs
19th Jun 2017, 12:10
The big boys don't fly when it's over the limits...

Phoenix heat wave: Too hot to fly? - 3TV | CBS 5 (http://www.azfamily.com/story/35664500/phoenix-heat-wave-too-hot-to-fly?utm_source=fark&utm_medium=website&utm_content=link&ICID=ref_fark)

Clare Prop
20th Jun 2017, 06:00
By this logic, if the performance chart for a PA28 only includes headwinds up to 15 knots then if it goes above that I can't take off or land....of course there is nothing in the "limitations" section of the POH about this

Are people really still using the little black AFMs? I thought they were legally discredited a long time ago. Though I see the text books and exams still have the "Cessna" graphs even though "real" Cessna manuals use tables.

john_tullamarine
20th Jun 2017, 08:29
headwinds up to 15 knots

Excursions which, clearly, are conservative probably aren't in question

the little black AFMs? I thought they were legally discredited

All out of vogue unless specifically approved, I suggest.

However, in general, the DCA approved P-charts were a reasonable compromise between simplicity, accuracy, and conservatism. As you would be well aware, some were a tad average ..

le Pingouin
20th Jun 2017, 10:29
Clare, you've got the logic arse-about. The performance chart would have to only include headwinds above 15kts for your analogy to work. More headwind is safer. More temperature is not.

andrewr
20th Jun 2017, 12:56
Excursions which, clearly, are conservative probably aren't in question

How do you feel about a "Normal Procedures" takeoff in a 172 with flaps 0 and 70-80 KIAS climb, when the performance charts are based on flaps 10, 56 KIAS climb?

Or a "Normal Procedures" landing at 60-70 KIAS when the performance charts specify 61 KIAS?

Neither are on the conservative side, and there are no performance charts or tables for Normal Procedures, only Short Field. If you're not using the charts anyway, why does it matter if the temperature is outside their range?

(And if you ARE using the charts for Normal Procedures, that's worse, because you can pretty much guarantee that you won't achieve anywhere near the chart figures.)

The big boys don't fly when it's over the limits

I imagine their charts are compiled somewhat differently and they fly the chart speeds every takeoff and landing. Not to mention things like derated takeoffs that require more runway, V1 speeds etc. - they mean that the performance calculations are more critical.

If the runway is short and you find yourself consulting the charts, I would certainly be cautious about exceeding the temperature range. In those circumstances I might be reconsidering even if it is within the range of the charts. But a blanket statement that aircraft must be grounded seems extreme.

runway16
20th Jun 2017, 23:54
http://www.pprune.org (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QFuGHp-EhFZItoR97k6NQH1SLUCEwuUiXatYGsR3rXqqiMmgucGd_8LMe5TysCGk5bf PEWM0WsIcSz6N0qOx01--iJLPrYy20WrWEvWiA8gyk6unwUQ_TXI=&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==) Flight Safety Information http://www.pprune.org Flight Safety Information June 20, 2017 - No. 123
ARGUS 2017 TRAINING COURSES (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK4) Incident: Cathay Pacific B744 at Hong Kong on Jun 19th 2017, gear problem after departure (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK5) Incident: British Airways B772 at Kuwait on Jun 16th 2017, engine shut down in flight (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK90) Incident: Atlasjet B738 at Istanbul on Jun 18th 2017, lightning strike (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK89) Phoenix flights cancelled because it's too hot for planes (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK86) Here's a Free Study Guide for Passing the FAA's Commercial Drone Test (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK85) FAA Boss Outlines Brexit Safety Concerns for UK Aviation (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK84) Global demand for airline service lifts airplane forecast to new high (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK83) EasyJet to deploy aircraft fault prediction tech (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK82) Dubai's flying taxi to soar by year-end (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK81) Airline industry facing a massive shortfall of pilots, survey says (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK80) Sharp-nosed Japanese jetliner could be game changer for U.S. flyers (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK79) Boeing planning on hypersonic jets for commercial flights (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK78) Boeing launches new jet with flurry of orders (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK77) GE Tells Boeing It Won't Join Three-Way Race on 797 Plane Engine (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK76) NATS and CAAi sign international cooperation agreement (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK75) BOWTIE RISK MANAGEMENT WORKSHOP...July 18 - 19, 2017 (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK61) Position Available:...Operations Manager Flight Data Connect (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK60) Magnetic space tug could target dead satellites (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK59) Graduate Research Survey Request (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK22) ADVERTISE WITH FLIGHT SAFETY INFORMATION (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK23) Today's Photo (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#LETTER.BLOCK24) http://www.pprune.org (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QFpqUUBDqYlQNsQUmE6_pksBDjl7vLNvENMsQAJWheqs2ufshoY1O0NOxnGM VNA7erXS6WSXkIOzMCH-4Hf6MdrYJZBfgYMHJwPXeKeG8XEqMeVAWB_De4XPHRVCXse9bPSg15TVkLa6&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==)
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Incident: Cathay Pacific B744 at Hong Kong on Jun 19th 2017, gear problem after departure


A Cathay Pacific Boeing 747-400 freighter, registration B-LIA performing freight flight CX-3290 from Hong Kong (China) to Anchorage,AK (USA), was climbing out of Hong Kong's runway 07L when the crew requested to stop the climb at 7000 feet reporting a gear problem and advised they would need to dump fuel and return to Hong Kong. The crew further advised they wanted to check whether there is any smoke from the right hand side, if not, they would start their fuel dump. The crew reported about 5 minutes later that they were now ready for a fuel dump, commenced fuel dump and returned to Hong Kong for a safe landing on runway 07L about 85 minutes after departure.

The occurrence aircraft remained on the ground for about 18 hours, then departed again and is estimated to reach Anchorage with a delay of about 19 hours.

http://avherald.com/h?article=4aa8ceee&opt=0 (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QF9qBP9by9wBVVrbiK8TW1rTMKplPx2S82kZNXbBiX0N1sMlVw2I4HIb_BhP ZWY4aQnToFDfgfi1_JF0gG_dSS8-Bokeqv-NTbMrGFMX6p-iA1hkPfeQH8qlcAKf1E98wHp8l_BwoVIzJWgAGFyBgpBrBFvxaf1fPA==&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==)

Back t (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)o Top (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)
Incident: British Airways B772 at Kuwait on Jun 16th 2017, engine shut down in flight


A British Airways Boeing 777-200, registration G-VIIH performing flight BA156 from Kuwait (Kuwait) to London Heathrow,EN (UK), was climbing out of Kuwait when the crew stopped the climb at FL160 reporting an engine (GE90) failure. The crew shut the engine down and returned to Kuwait for a safe landing on runway 33R about 45 minutes after departure.

Passengers reported the captain announced they had needed to shut one engine down.

The occurrence aircraft is still on the ground in Kuwait about 87 hours after landing back.

http://avherald.com/h?article=4aa8ccc1&opt=0 (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QF9qBP9by9wBAE_9yOIMTNwvGq_HP8Bi3lUQ8IcnDtduH6rNZT_8qBrLlsUn lnPyvyFkE3mRe9j8w7jxvtVrkT9qhXH21CtBsUOKEZiDuXq6hK2IaaXY_8-JGjL8eDWwzHdkFzmvHUcvwYASW3CiMvvvX520sb5aYw==&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==)

Back t (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)o Top (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)
Incident: Atlasjet B738 at Istanbul on Jun 18th 2017, lightning strike


An Atlasjet Boeing 737-800, registration TC-SNT performing flight KK-9764 from Istanbul (Turkey) to Tbilisi (Georgia), was climbing out of Istanbul when the crew stopped the climb at FL180 following a lightning strike and decided to return to Istanbul for a safe landing on runway 35L about 50 minutes after departure.

The occurrence aircraft received damage and remained on the ground for 10.5 hours before returning to service.

http://avherald.com/h?article=4aa8cabf&opt=0 (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QF9qBP9by9wBSAnKQWPwKf4vO2_IMvrcp0dzs7Iryy3hBPUBMm2P1aEG5XbR 9CG_mbu4dIP1XoenJvIzRE5cPyxDCgYqqENRZp158ZdG0eSJ9FjalClhFZNr 7E9g4mYDroxiUEKozN2t2zZ9UQpcMXcEzJ54QpK_VQ==&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==)

Back t (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)o Top (http://www.pprune.org/{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/#Top)
Phoenix flights cancelled because it's too hot for planes
http://www.pprune.org
A plane is silhouetted against the sky as it takes off from Heathrow Airport 19 December 2002 in London, England.

Even for Arizona, the temperatures are high - hot enough to stop flights
As temperatures climb in Phoenix, Arizona, more than 40 flights have been cancelled - because it is too hot for the planes to fly.

The weather forecast for the US city suggests temperatures could reach 120F (49C) on Tuesday.
That is higher than the operating temperature of some planes.

American Airlines announced it was cancelling dozens of flights scheduled to take off from Sky Harbor airport during the hottest part of the day.

The local Fox News affiliate in Phoenix said the cancellations mostly affected regional flights on the smaller Bombardier CRJ airliners, which have a maximum operating temperature of about 118F (48C).

The all-time record for temperatures in Phoenix is just slightly higher, at 122F, which hit on 26 June 1990.
The cancelled flights were scheduled to take off between 15:00 and 18:00 local time.

Why can't planes fly?

At higher temperatures, air has a lower density - it is thinner. That lower air density reduces how much lift is generated on an aircraft's wings - a core principle in aeronautics.

That, in turn, means the aircraft's engines need to generate more thrust to get airborne.

It's a well-known problem - a 2016 report from the International Civil Aviation Organization (ICAO) even warned that higher temperatures caused by climate change could "have severe consequences for aircraft take-off performance, where high altitudes or short runways limit the payload or even the fuel-carrying capacity".

Those problems are why many countries in the Middle East, and some high-altitude airports in South America, tend to schedule long flights for the evening or night, when it is cooler.

Bigger aircraft like Boeing 747s and Airbus models have a slightly higher operating temperature, and have not been affected by the heat in Phoenix.

An American Airlines statement provided to The Arizona Republic newspaper said those jets should be fine up to 126-127F (53C) - just a little higher than what is expected.

Those temperatures, however, are forecast for the aptly named Furnace Creek in Death Valley, in California, with some areas expecting new temperature records on Tuesday.

The Death Valley National Parks Service has issued a warning to visitors to avoid hiking after 10am, and to "travel prepared to survive".

http://www.bbc.com/news/world-us-canada-40339730 (wlmailhtml:{ABC98F6D-DD64-41A5-B6D7-FE031551F7D6}mid://00000045/!x-usc:http://r20.rs6.net/tn.jsp?f=001MEp_UfF8tjl5Cp3gEP41yInjgim9FcoWciFWUfMwci591r-AovU-QF9qBP9by9wBqs2wPrHsWt-kjDOo11-kL4aTcE--jiFZEvCqgkiUbn3eqb3fzFwHsHyaHbVsuisYG0V1DEGNBrNkNzx6EUsVMOE6 DUnS1yTcst8bESSUrrkMV29KtV3l1boH2tgfDjzo3E3egyX9nDnihsHQ7fW7 8A==&c=7UlpwboiX654TREGzPCe0TkalrRLYOQxG8yt2crO6HLtNSkL5BcA0w==&ch=Kfm0hEtgJNI0xdMdMoGmKHog1l_1-_1msNJ1FAmsT7VBNJQX6LGR5Q==)

djpil
21st Jun 2017, 00:38
Excursions which, clearly, are conservative probably aren't in question ..What is the applicable rule?
How is that rule applied to each parameter?

Clare Prop
21st Jun 2017, 04:52
Where do CASA's declared density altitude charts fit into all this, they don't mention temperature

andrewr
21st Jun 2017, 05:09
A very good question!

Declared density is a substitute for knowing the temperature. You can use a standard temperature and higher altitude in your charts - exactly what this opinion says you are not allowed to do.

So maybe you are not allowed to use declared density any more, or maybe CASA didn't think things through when they wrote the opinion.

underfire
21st Jun 2017, 09:44
7.4 AFM – High ambient temperature operations
Background: The Convenor received the following information of interest. The attached CASA response confirms this is not a CASA/RAPAC responsibility – rather manufacturers – but RAPAC members should take note:
“Many areas of Australia have encountered above 40 degree C temperatures in recent times, and will likely encounter them again in subsequent years. The attached map from the BoM website chronicles the period 1 November to 31 January.
CASA was asked: if an aircraft's AFM caps performance data at 40C, can the aircraft still legally fly when the ambient is above 40C? Of note: "unless a declared emergency situation exists, if ambient conditions exceed the limitations set out in the AFM, including the range for which performance data is provided, the aircraft must be grounded". This is a significant announcement and has widespread implications. Insurance companies rely on a pilot's compliance with CASA's rules and regulations when considering if a claim is to be processed.”
Discussion: The Convenor indicated that the item had been included for the information of members and to raise awareness of the issue.
Mr Walker confirmed CASA’s position that aircraft needed to be operated within the parameters published in an aircraft flight manual and there was no provision to extrapolate performance data beyond that provided.


if an aircraft's AFM caps performance data at 40C, can the aircraft still legally fly when the ambient is above 40C?
Of note: "unless a declared emergency situation exists, if ambient conditions exceed the limitations set out in the AFM, including the range for which performance data is provided, the aircraft must be grounded".

Where do CASA's declared density altitude charts fit into all this, they don't mention temperature

reading thru 6 pages of responses, where is this going?

What if you cannot determine your weight !?!?! (okay I added the !?!?!)
then you use the MTOW for the ac...FFS. (sorry, but if you cannot determine your weight, how did you determine loading for the ac? )
In reality, if you are a driver and cannot figure out your MTOW, then it does not matter what the temperature is, you should be restricted from taking off.

if an aircraft's AFM caps performance data at 40C
including the range for which performance data is provided,

What is MTOW for the ac based on?

The MTOW and associated parameters with ISA with airport altitude and temperature are well defined.

ISA and ISA d....is there an understanding of the ISA temp/altitude, (and MTOW) and what one must do when NOT within those parameters???

With the ISA D, you can determine what MTOW is based on per the temperature D. If the temp is higher than listed, you need to weight limit, and calc the new MTOW.
When ac look at restricting ops with temp, it means that IT cannot meet DEP obstacle clearance EO, and UNLESS you have an EO approved procedure, thus must follow the SID procedure.

In reality, I have significant concerns with drivers who have no understanding of MTOW, associated temperature limitations with the associated effects, nor the comprehension of the necessity to calculate take off weights for their aircraft..

john_tullamarine
21st Jun 2017, 13:01
How do you feel about a "Normal Procedures" takeoff

In the first instance, quite obviously, I can't recommend it. However, for me, I don't have a problem for my takeoff and am comfortable that I can argue the toss were push to come to shove. In any case, I prefer to follow the POH data and OEM recommendations for light singles to avoid the problem.

If the POH doesn't have any data relating to a configuration/speed schedule, then the pilot is on his/her Pat Malone if choosing to operate in such a manner. If one isn't able to justify the activity, perhaps one ought to fly it as appropriate for whatever charts are extant ?

The big boys don't fly when it's over the limits I imagine their charts are compiled somewhat differently

The charts are more complex and cover considerably more concerns. However, at the end of the day, the two areas have their similarities

and they fly the chart speeds every takeoff and landing.

Indeed .. and I really can't see why the light aircraft can't be operated with a similar philosophy ?

Not to mention things like derated takeoffs that require more runway, V1 speeds etc. - they mean that the performance calculations are more critical.

All the numbers are critical if the operation be limiting. However, there is no a priori reason why data for the heavy need be more accurate than for the light .. other than the cost of development consideration.

and you find yourself consulting the charts

as one should, unless the data be the same as a previously determined case.

I would certainly be cautious about exceeding the temperature range.

Indeed, as would I.

What is the applicable rule? How is that rule applied to each parameter?

As we both know, there is none. Ergo, the second concern is moot. Equally, both you and I are able to generate a reasonable argument to cover reasonable excursions.

I probably ought to have kept my peace and not posted .... ?

Where do CASA's declared density altitude charts fit into all this, they don't mention temperature

I think they are an historical anachronism which hasn't yet been consigned WPB, round.

if an aircraft's AFM caps performance data at 40C

One ought to be VERY cautious when it comes to extrapolating temperatures .. OAT affects both airframe and engine and, in the absence of specific data relating to both, especially the engine, it can get rubbery .. quickly.

compressor stall
21st Jun 2017, 13:21
This is one of those - sadly increasingly common - occasions where I wish I had the rest of my flying career (~20 years) behind me, not in front of me.

john_tullamarine
21st Jun 2017, 13:55
Isn't that the case ? Guess I'm closer to 30 years older than your good self, then.

kaz3g
21st Jun 2017, 14:21
On topic...


http://www.abc.net.au/news/2017-06-21/extreme-us-heatwave-grounds-arizona-las-vegas-flights/8637278u


kaz

gerry111
21st Jun 2017, 15:20
Kaz, That's coming up: "SORRY, PAGE NOT FOUND." for me.

kaz3g
22nd Jun 2017, 03:16
Arizona flights grounded as temperatures set to soar to 50C in extreme heatwave
Updated yesterday at 5:20pm

Arizona flights grounded as temperatures set to soar to 50C in extreme heatwave - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2017-06-21/extreme-us-heatwave-grounds-arizona-las-vegas-flights/8637278)

andrewr
22nd Jun 2017, 04:14
How do you feel about a "Normal Procedures" takeoff?

In the first instance, quite obviously, I can't recommend it.

In any case, I prefer to follow the POH data and OEM recommendations

and they fly the chart speeds every takeoff and landing.

Indeed .. and I really can't see why the light aircraft can't be operated with a similar philosophy ?

I'm not sure whether you're recommending flying the performance chart speeds or the recommended speeds? They are different.

Cessna seems to have recognised that most of the time, the 172 will be flown off more than adequate runways.

When the is doubt about runway length, they assume that short field procedure will be used and that is what they use in the charts. But they do not recommend short field procedures for normal operations - the normal procedures presumably have more safety margin.

Cessna also seem to assume that pilots are smart enough to figure out when runway length might be an issue.

Where do CASA's declared density altitude charts fit into all this, they don't mention temperature?

I think they are an historical anachronism which hasn't yet been consigned WPB, round.

What temperature do you use for performance calculations when operating into a location without a forecast?

One ought to be VERY cautious when it comes to extrapolating temperatures .. OAT affects both airframe and engine and, in the absence of specific data relating to both, especially the engine, it can get rubbery .. quickly.

It's just the laws of physics, and they are in fact well understood.

john_tullamarine
22nd Jun 2017, 06:14
I'm not sure whether you're recommending flying the performance chart speeds or the recommended speeds? They are different.

Granted. If one doesn't have performance data, then there remains the problem of justifying the takeoff/landing post mishap. I am comfortable with both approaches but I have an appropriate engineering background to do some approximate sums to keep myself sweet.

Cessna seems to have recognised that most of the time, the 172 will be flown off more than adequate runways.

Aye, there's the rub. At what point does one perceive a problem ?

Cessna also seem to assume that pilots are smart enough to figure out when runway length might be an issue

One would hope that pilots are appropriately conservative so that such would be the case.

What temperature do you use for performance calculations when operating into a location without a forecast?

At present, the declared data is fine. Also, the BOM site data provides quite useful information. Apply whatever conservatively and, where feasible, carry an alternate to somewhere with forecast data. I really don't see a problem with this one.

(Guess it's not all that much different in principle to detailed software development work.)

Ixixly
22nd Jun 2017, 09:52
Out of interest, I haven't read everything in this thread but note a lot of people choose the Common sense approach of extrapolating data for higher temps based on the data in the POH.

A lot of newer Aircraft seem to have a Temp Limit, when you extrapolate the Data though to beyond that Temp Limit the Aircraft could still perform when doing so, but there is still this limitation.

If you extrapolate beyond the data presented, how do you know for certain that it will perform?

When designing W&B Programs in the past using Excel for various Aircraft I've often noted that a lot of Aircraft don't follow simple extrapolation, they require complicated Polynomial Equations to be able to do so, something beyond I'd say the vast majority of Pilots and unless you evaluated the entire data set you would never be aware of it, how are you certain that beyond the 40 degrees performance data stated in your POH that Performance of the Aircraft wouldn't start to significantly decrease at say 45 degrees and beyond?

john_tullamarine
22nd Jun 2017, 11:36
lot of people choose the Common sense approach of extrapolating data for higher temps

.. if you don't have the engine data sets, in particular, you have not much idea at all of what happens at higher OATs other than presumptions based on general principles. Extrapolation into the higher OATs is not a routinely good idea, I suggest.

how are you certain that beyond the 40 degrees performance data stated in your POH

I would think one would have very little idea of what might happen.

Re the W&B considerations, I presume you are referring to the usual sloping limit lines on the weight x CG envelope ? They will only be first order there and, if one uses the weight x moment presentation, quadratic .. but, for a computer solution, why would you bother with the latter ? Not a big problem, I would have thought ?

megan
22nd Jun 2017, 16:16
In the Cessna 404 manual take off and landing tabulated data only goes to 40°C, however climb data, both dual and single engine, goes to 50°C.

How can we say 40 is the operational limit because the take off chart only goes that high, but climb data goes to 50?

I would have thought a prudent pilot would work backwards from the climb charts. Ensure s/he could reach the required gradient at temps between 40 and 50, and then from the take off chart determine the distance from a density altitude calculation.

All the Cessna manuals I've seen have a preamble to the performance section which says,Demonstrated Operating Temperature

Satisfactory engine cooling has been demonstrated for this airplane with an outside air temperature 23°C above standard. This is not to be considered as a operating limitation. Reference should be made to Section 2 for engine operating limitations.Notably the preamble also says the performance information allows planning with reasonable accuracy, not exact, as the preamble again says, it assumes "using average pilot technique (however you quantify that) with an airplane and engines in good condition". I don't see how using DA when temp is 40< to extract T/O data transgresses any rule, regulation etc The climb charts would suggest that 50°C is the practical limit, because that's as far as the chart goes. Why else have the climb charts go to 50 if take off is limited to 40? Inversion? Where do you source that data?

Ixixly
22nd Jun 2017, 17:19
john tullamarine, I should have been more specific, in a lot of my W&B Programs I've also included the ability for it to give you the TODR, LDR etc...etc..., was referring to those requiring Polynomials, not the CofG graphs and such. I agree entirely on your first point in response to my post.

megan, I understand what you're saying, but how do you know how the Aircraft will perform when above the 40degrees? You can extrapolate but you're assuming that the trend is continuous, perhaps after 40 degrees the Performance will decrease markedly?

I think we can all acknowledge that aircraft will have a temperature limitation, whether it's been put into your POH or not, it's common sense, eventually there has to be a temperature beyond which it's just not safe to be operating the Aircraft! Without the data showing this point how do you know where it is?

Most POHs/AFMs won't have it because, I'd suggest, they simply never tested it under extreme conditions above 40 degrees and therefore don't have the data. For all our fancy tech and know how it seems to be most of the information we have from our Manuals really came from someone jumping in the damned thing and taking it for a flight to figure out what will happen. I know it's more complicated than that but essentially that's what the data in them all boils down to.

I'm not saying that I necessarily agree with CASAs interpretation, BUT, I believe we all need to be reminded that if you choose to use your Aircraft without any proven data from the Manufacturer or another reliable source, you've basically just become a Test Pilot.

IMHO that really needs to be the biggest take away from this whole idea, extrapolation is fine and gives you a guide but you need to be prepared at some point to say "I don't know" when trying to decide if your Aircraft can comfortably and safely operate at such extreme temperatures and from there either seek the information from someone reliable who DOES know (Not just Joe Bloggs who has taken off tons of times at 45 degrees!), then if you can't get that data, perhaps it's time to sit back and wait for a few hours for things to cool off?

megan
22nd Jun 2017, 17:55
but how do you know how the Aircraft will perform when above the 40degreesWe do know how the aircraft will perform in the climb up to 50°C, both dual and single engine, because the manual has a chart giving the performance up to that temperature with no extrapolating involved. It's data in the flight manual, provided by the manufacturer.

Why have a chart giving the climb data to 50, if 40 is the limit for take off? Why would the manufacturer go to the expense of developing that climb data?

Edited to add: The SR22 take off data goes up to 50°C, and the preamble includes the noteFor operation in outside air temperatures warmer than this table provides (50°C), use caution.Difficult then to see how the temperature on the take off chart can be considered a limit.

john_tullamarine
23rd Jun 2017, 01:25
I've also included the ability for it to give you the TODR, LDR etc...etc..., was referring to those requiring Polynomials

Without knowing what you have done in the past, I can only speculate. However, if one (as I suspect you are doing) intends to represent the physical charts by a computer implementation, there are three basic ways to go about it (with the test for acceptability being the delta between model and AFM data set .. not much in the way of linear data in the AFM)

(a) first principles .. too hard to figure the empiricals to get adequate accuracy so one leaves this for the OEM .. as in the EFB etc implementations these days

(b) polynomial regressions. Generally, too difficult to run multivariate regressions and achieve adequate accuracy so the usual way is to run single regressions for the printed lines and then either run interpolations or on the fly regressions for between line points .. great fun .. been there ... done that for a number of AFM data sets with very high accuracy albeit with the attendant boring slave labour to make it all work OK .. especially if the data set has numerous discontinuities .. painful. I presume this is the way you played with the stuff ?

Big potential for getting the fingers burnt with extrapolation, though, depending on the order of the the equation and what antics it produces in the extrapolated region where one doesn't have data points to constrain the regression .. one can guard against this but, in general, a risky business.

(c) interpolations, commonly splines. Useful for small data sets but I always preferred setting up the regression analyses and go from there.

how do you know how the Aircraft will perform when above the 40degrees?

The main concern is hidden discontinuities in the engine data pack. If you have some other data for the higher OATs, then you probably are reasonably safe with extrapolation unless there be some (strange) significant differences at the takeoff rating. Without such comfort, extrapolating the engine data is, at best, risky business ..

it seems to be most of the information we have from our Manuals really came from someone jumping in the damned thing and taking it for a flight to figure out what will happen.

That would be most unusual as the aim is to end up with something which can be used to model performance. Common practice is to model the performance and then use FT to sample test the accuracy of the model. Often it then becomes an iterative exercise to end up with an acceptable final accuracy in the model .. which then goes into the AFM data set.

We do know how the aircraft will perform in the climb up to 50°C, both dual and single engine

That is a useful source of comfort, I suspect.

Why have a chart giving the climb data to 50, if 40 is the limit for take off?

A question of limitation, then, becomes a legal question, rather than an engineering concern ?

megan
23rd Jun 2017, 01:57
An answer from the horses mouth so to speak. I asked Cessna, Wichita, the followingThere is an argument in the community here as to whether the 40°C on the take off charts is a limit, or not.

ie: is take off permissible at temperatures in excess of 40°C.

I note in the 404 manual, dual and single engine, climb charts are provided for temperatures up to 50°C.

Do you consider the following an acceptable means of flight planning on the 404 when temperatures are in excess of 40°C and up to 50°C?

1. Determine from the climb charts the regulatory stipulated gradient.

2. Calculate the density altitude.

3. Determine from the take off chart a temperature and pressure altitude that gives the same density altitude.

For example, 50°C at zero pressure altitude the density altitude is 4,158 feet.

Entering the take off chart 1,000 feet pressure altitude at 40°C will give a density altitude of 4,210 feet.

4. Use the 1,000 feet PA, 40°C take off distance.

Is the same principal of using the density altitude to calculate take off distance when temperatures are above 40°C permissible, or is 40°C considered an operating limit for the singles (172, 207 etc)?

A view, which has currency in the community, is that you may not take off if the temperature is over 40°C.Their replyThe temperatures on the performance charts are provided to cover the majority of average operations. The temperature limits of these charts were not intended as a limitation for the aircraft, but simply what the aircraft was tested to. Simple interpolation as you have performed is appropriate.

john_tullamarine
23rd Jun 2017, 02:12
Good one, sir.

FGD135
23rd Jun 2017, 05:49
Bravo, Megan :D

Just a little word in defence of Declared Conditions: JT seemed to be implying that these should be headed for the bin, but I say:

What else can you use when planning your payload uplift from a place a few days, or weeks ahead of now? You obviously don't have ambient conditions, and I believe the regs stipulate that you must use the declared conditions.

Unlike probably 90% of Australian pilots, I have actually used them in anger, and can attest to their convenience.

Here is a great big hint to the people behind the NAIPS app for the iPad/iPhone:

Include the declared conditions in your app, somewhere. And while you are at it, get it to present the conditions not as a density altitude, but as a temperature and pressure altitude. That would be really good. Do it. Just do it.

Lead Balloon
23rd Jun 2017, 09:18
The temperature limits of these charts were not intended as a limitation for the aircraft, but simply what the aircraft was tested to.I'm pretty sure you'd get an equivalent answer if you asked the equivalent question about the maximum demonstrated crosswind number (which is why the word "demonstrated" is in the description of the number).

ANCIENT
26th Jun 2017, 07:10
It is interesting that this thread has concentrated on performance issues. In high or low temperatures the physical limits of the machinery can be of more concern than the performance.
All aircraft have environmental limits.
The Bell 206L3 has a max ambient air temp of 51.7c (125F) and I can say from first hand experience flying in temps around this limit has one concerned about Gearbox temps/oil temps etc.
The R22 has a stated demonstrated limit of 38C at sea level due to cooling issues. Again first hand experience of oil temp on red line when operating a standard R22 in the tropics. Look at R22s used for mustering and you will notice they have been fitted with a larger oil cooler to aleviate some of the problem. What are these high ambient temps doing to other lubricated components.
Take off performance may be the least of the issues of operating in high ambient temps.

megan
27th Jun 2017, 01:41
Take off performance may be the least of the issues of operating in high ambient tempsYou are quiet right, and most of the FAR 23 manuals I've looked at have the following statement in the performance section,Satisfactory engine cooling has been demonstrated for this airplane with an outside air temperature 23°C (41°F) above standard. This is not to be considered as an operating limitation. Reference should be made to Section 2 for engine operating limitations.

megan
22nd Oct 2017, 05:31
Perusing the old Digests kindly provided above in the forum, I came across this article in issue #33, which I reproduce in its entirety. Note density altitude is the focus, temp even goes to 45°C on the chart, and absolutely no mention of temp being a limit, just DA.

LIGHT AIRCRAFT TAKE-OFF PERFORMANCE

Temperature and Altitude Effects

A review of take-off accidents involving light aircraft has shown that an appreciable number of them can be attributed wholly or in part to a failure to allow for the effects of reduced air density arising from high temperature, high altitude, or, more particularly, from a combination of both.

Two separate effects must be considered;

(a) The effect of reduced air density on take-off
distance;

(b) the effect of reduced air density on climb
performance.

Both of these aspects will be examined in turn.

The Effect of Reduced Air Density on Take-off Distance

The normal takeoff consists of a full throttle run along the ground, a lift off at the take-off safety speed, and a climb away at this speed until a height of 50 feet is reached.

The take-off safety speed is defined as 1.2 Vs, where Vs is the power off stalling speed.

The indicated stalling speed of an aircraft depends, principally, on the aircraft’s weight, power setting and flap position. Changes in air density do not change the indicated air speed at the stall. Every pilot is aware, however, that under conditions of reduced air density the true air speed is greater than the indicated air speed; thus, in a take-off under high temperature conditions, the prescribed higher true air speed and the distance required to reach this speed will be greater. Alternatively, for a given take-off distance the gross weight of the aircraft and hence the take—off safety speed will have to be reduced in order to provide for a safe operation within the available distance.

Another major effect to be considered is the reduction of engine power output arising from reduced air density. In most light aircraft, take-off power is the full-throttle setting of its unsupercharged, or normally aspirated, engine. Changes in air density produce changes in the full throttle power of such engines. Any reduced air density means less air available for combustion and a fall-off in take-off power. The reduction in power is approximately proportional to the reduction in air density.* This reduction in available power means that less thrust will be available for accelerating or climbing the aircraft. lt can be seen, therefore, that reduced air density will not only demand longer take-off runs to allow the aircraft to accelerate to the higher true airspeeds but it also imposes the penalty of reducing the power available to achieve this acceleration. The take-off distances required are therefore greatly increased even for small reductions in air density.

The information provided in handbooks by the manufacturers of light aircraft is usually insufficient to take account of all the major variables and the Department of Civil Aviation has undertaken the production of the PL Charts (Performance Charts for Light Aircraft) to assist pilots in their calculations. For most aircraft types, the manufacturers data has been checked by flight testing in Australia and the chart data is based on these test results.

The chart indicates the maximum permissible gross weight for take-off after aerodrome pressure height, outside air temperature, take-off distance available and wind velocity are taken into account. Fifty per cent of the reported head wind component and 150 per cent of the reported tail wind component have been used in the construction of the chart and the take-off distance has been increased by a factor of 1.15 as is shown in the notes on the chart. The following example illustrated in the chart will show how the chart is used.

* In the case of a supercharged engine this effect is overcome, within limits, by compressing the air and thus restoring the air supply.

Airfield pressure height which may be read from your altimeter after setting 1,013.2 mb. = 920 feet

Outside air temperature measured in the shade : 113°F or 45°C

Take-off distance available = 1,550 feet

Wind velocity component = Nil

(1) Effect of Air Density Change

Enter the chart at °“START HERE" and find the intersection of the airfield pressure height (APH) and the outside air temperature (OAT). The point of intersection indicates the density height at which the next segment of the chart to the right should be entered. This density height is determined by the relationship of the APH/OAT intersection with the horizontal lines drawn through the upper three segments of the chart. The bottom line has a zero or standard sea level value as determined by the intersection of the zero airfield pressure and the standard 15°C temperature. Each successive line drawn is a 1,000 feet increment in density height. Thus it will be seen that the density height in this example is 4,500 foot which means that the density of the air under the conditions stated in the examples is the same as would exist at a height of 4,500 feet under conditions of standard atmosphere, At this point it is of interest to note the effect of temperature on density height. If the OAT had been 13‘”C the density height would have been the same as the airfield pressure height, i.e., 920 feet and, with an even lower temperature of 5°C (41°F) the equivalent of sea level standard conditions would prevail. It will become apparent from this why a light aircraft exhibits a lively performance on a frosty morning. Now move on to further corrections in the example.

(2) Effect of Take-off Distance Available

Move to the right on the chart until you intercept the line representing the take-off distance available and then move vertically downwards to the next correction.

It may be seen that, in the particular conditions of this take-off, no reduction of the maximum permissible gross weight would have been necessary had the available length of run been equal to or greater than 2,400 feet. Since the available length is only 1,550 feet, however, it is immediately apparent that the gross weight for take-off will need to be reduced.

(3) Effect of Wind

Continue to move vertically downwards to intercept the ambient wind velocity Line and then move horizontally to the left and read from the scale the maximum take-off weight permitted under these circumstances, i.e., 1.570 lb.

(4) Take-off Safety Speed

Since the stalling speed varies directly with weight, the take-off safety speed will also vary directly with the take-off weight and for this case it may be read directly off the right hand side of the diagram as 43 Kts. I.A.S.

We are now in a position to see that under the conditions prescribed, the combined effects of limited take-off distance available and the reduced air density has demanded a reduction in the maximum permissible take-otf weight from 1,825 lb. to 1,570 lb.

The Effect of Reduced Density on Climb Performance

The Australian performance standards require that all light aircraft have a minimum gradient of climb after take-off of six per cent, This can be expressed as 6 feet of climb for every 100 feet of horizontal travel along the flight path, or 365 feet per nautical mile which is equivalent to a rate of climb of 365 feet per minute if the aircraft’s climbing speed is 60 knots (T.A.S.).

The climb gradient is greatly affected by even a small reduction of engine power because the power available to climb the aircraft is only the power in excess of that required for straight and level flight at the climbing speed.

We have already pointed out that any reduction in air density produces a proportionate reduction in engine power. Reference to atmosphere tables will show that air density falls about 3 per cent per 1,000 feet between sea level and 3.000 feet, reducing to 2 per cent per 1,000 feet at 16,000 feet. Thus it the aircraft is taking off in conditions of pressure and temperature which are equivalent to a height of 4,500 feet under standard conditions (i.e., a density height of 4,500 feet) the engine output under full throttle at constant r.p.m. will fall about 13 per cent. This amounts to a considerable reduction in the power available for the climb and the gradient of climb is correspondingly reduced. If the density is reduced to a point where the minimum climb gradient would not be achieved, the take-off gross weight must be reduced in order to restore the gradient and thus ensure a safe climb out over obstacles.

To show how this adjustment is calculated we must now refer to the Climb Weight Limit diagram in the PL Chart.

Climb Weight Limit

Enter the chart at the airfield pressure height and move vertically until the line intercepts the outside air temperature. Then move horizontally to the left to the point of intersection with the sloping reference line and then vertically downwards to the gross weight scale where it can be seen that the climb weight limit is 1,775 lb.

Points to be Especially Noted

The maximum permissible weight derived from our previous calculations based on runway length available was 1,570 lb., Whilst the weight limitation based on the climb requirements is 1,775 lb. The lesser of these two is the maximum permissible take-off gross weight, i.e., 1,570 lb.

If the aircraft's gross weight is held constant the effect of temperature on the length required for take-off at a particular aerodrome may be seen from the chart. Referring to our example again, you will remember that 1,550 feet was the minimum length required to lift 1,570 lb. when the temperature was 45°C (113"F). Drop the temperature to 13°C (55°F), which is standard for a pressure height of 920 feet, and for the same weight the take-oil length required is reduced to 1,170 feet. Check this on the chart at the point where a density height of 920 feet intercepts the vertical line of our example in the ‘distance available" segment of the chart.

Whenever a take-off in the type of aircraft to which the sample chart applies is to be carried out with a density height exceeding 3,800 feet, Some reduction of take-off (i.e., 1,825 lb.) must be made irrespective of the length of run available. This arises from the climb weight limitations of the aircraft.

Example:

Now try this example yourself using a ruler and sharp pencil.
Airfield Pressure Height ....,. . ,.... 1.500 feet
Outside Air Temperature ..,... . ..... 25°C
Take—off distance available . .... 1,900 feet
Head Wind Component 5 m.p.h.

It you have mastered the system you will agree that the take—off gross weight is 1,785 lb. and the take-off safety speed is 47 Imots.

KRUSTY 34
23rd Oct 2017, 05:20
Saab 340B engine start limit 47C so at Birdsville eg. a clever fast look at the temp got you going..

The SAAB AOM does state a limitation of 47 degrees C. During one insanely hot day in Sydney a few years ago the OAT actually peaked out at 47.6! The word from the Chief Pilot’s Office was, as long as it doesn’t hit 48, we were good to go. The rationale being, anything up to 47.9 is acceptable?

It seems you can delude yourself into believing anything if the circumstances dictate. :rolleyes:

Lasiorhinus
24th Oct 2017, 01:59
And you only need one prop to land in Sydney, anyway...

Old Akro
24th Oct 2017, 03:49
The SAAB AOM does state a limitation of 47 degrees C.

Measured how?

By whom?

With what equipment? Mercury thermometers, the common rotary dial gauges & digital gauges all rear differently with different reaction times or lag

Where? Engine compartment, ambient? ambient in the shade, ambient at aerodrome reference?

The limitation probably relates to hot fuel handling of the engine - which will have more to do with heat soak than ambient conditions.

The role of a pilot is to make judgement decisions, this is one of them .

KRUSTY 34
24th Oct 2017, 12:11
I would suggest it’s about common sense, and knowing where to draw the line.

OZBUSDRIVER
24th Oct 2017, 23:06
Megan, if you could pdf that letter and upload would do wonders for those not game enough to take it up to uneducated FOIs on the principles of flight. Density could be an argument....maybe too much of it between the ears:ugh: Or, grey matter lacking oxygen starving mental performance:\ Or, hot heads lack performance when it counts....bloody lawyers! Obfuscators Lacking Competency!

djpil
15th Dec 2018, 22:27
Getting into the hot weather down here so time to consider this again. (I only deal with small airplanes.)

Presumably where-ever you are supposed to get the temperature from for your performance calculations.... possibly even declared density?CAO 20.7.4 Aeroplane weight and performance limitations — aeroplanes not above 5 700 kg — private, aerial work (excluding agricultural) and charter operations states "Approved declared conditions may be used instead of actual pressure height and temperature" - the declared conditions are from CAO 20.7.0 as declared density altitude.

A couple of years ago, a note in the Exposure Draft of Part 91 (MOS for 91.1035 Aircraft Performance): “It is the intention that CAOs 20.7.4. …. will be subject of a project to review them and provide guidance material in the form of an AC in the future. Much of the content of the CAOs contain either certification standards or outdated information. CASA expects pilots to operate in accordance with the aircraft flight manual (AFM). All performance information in the AFM is produced and complies with the aeroplane certification standards.”
I've heard nought of that project since.

If one has a FAR 23 airplane not more than 6,000 lb maximum weight there are no performance weight limitations in the AFM so just work your way through CAO 20.7.4 and try to deal with the outdated information and Australian-specific certification standards within it.