CASA opinion: Aircraft must be grounded in temps over 40 degrees
- 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.
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?
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...
.
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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).
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).
needless operation within is a bit on the scary side if something goes bang
Last edited by megan; 13th Apr 2017 at 05:38.
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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.
- 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.
Kaz
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)
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)
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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.
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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)
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)
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conservative and non-conservative extrapolation and appropriate usage
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.
Basically, you may not operate outside the limitations of the aircraft and/or extrapolate beyond the performance limits of your aircraft's performance charts
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.
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.
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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.
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.
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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.
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.
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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.
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.
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.
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.
Of course, Kaz can use trial and error in the Auster to determine it.
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,
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,
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.
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.
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.
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.
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And I think it's your turn to buy the red after that
Kaz
Ps. There is a flyin to Ian Dickson's and Jenny Houghton's on Anzac Day.