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-   -   CASA $1,000 Useless Compass Check (https://www.pprune.org/pacific-general-aviation-questions/554236-casa-1-000-useless-compass-check.html)

thorn bird 10th Jan 2015 10:47

Oh god,
I listen to you guys and I wonder.
We get what we deserve, creamy is as usual right.
CAsA has the industry bluffed,bamboozled and completely, comprehensively beaten.
Here we are arguing over a $1000 dollar completely unnecessary maintenance requirement and while we are distracted arguing over horse ****, the bureaucrats stealthily manoeuvre to chop the industry off at the ankles.

As Creamie says, thousands of pages of horse **** and we are still not safe.
Spare me, we may just as well pull the pin now and go find something else to amuse ourselves, aviation in Australia is stuffed, save yourself some money and quit while your ahead.
There is just too much money locked up in secondary airports alone to defend against corruption, which was probably set up a long time ago. Pay day is rapidly approaching for the hierarchy, hey look at what a recent Foreign minister won, farms in NZ??? what do you think them that facilitated the sell off of GA airports will get?? We are talking about billions of $$$. These people are very very clever, unfortunately much cleverer than us.

Sunfish 10th Jan 2015 18:31

Against my better judgement, I'm going to weigh in on this. I think a compass calibration under flight conditions is a worthwhile thing.

I have personally experienced sophisticated navigation and autopilot systems going haywire - admittedly on a yacht, at night. The results are a raft of confusing and contradictory indications and my only means of determining which parts of the system were lying to me was my Sestrel magnetic compass.

I understand that a similar failure mode caused the loss of an Airbus in the Atlantic. Clock compass and ASI - first principles in an emergency.

To put that another way; a man with one watch knows what time it is. A man with Two is never sure.

Creampuff 10th Jan 2015 20:39

So all of that leads you to the conclusion that magnetic compasses should be mandatory for helicopters, and those compasses should be the subject of mandatory periodic calibrations by licensed aircraft maintenance engineers, on pain of criminal prosecution?

If so, like I said, it's no wonder the GA community is such easy pickings for the regulator.

(As a matter of interest, Sunny, when was your yacht's Sestrel magnetic compass last calibrated by a licensed compass adjuster? When is it next due for a mandatory calibration? What penalty do you face if you go to sea without your yacht's compass having been calibrated by a licensed compass adjuster?)

Mach E Avelli 10th Jan 2015 21:50

I'm with you Creamie. We spend hours studying compasses when we do our theory,whether it be for a pilot licence or a yacht master ticket. On my boat I often compare GPS against compass when in calm water so that there is little drift to worry about. Or if I am really keen I run a transit check, which to the uninitiated is similar to being on a taxiway or runway aligned with a known bearing..That way I know that ithe compass is within 5 to 8 degrees on all points. That is good enough because I can't steer better than that anyway.
The regulations require pilots to do an instrument check every flight. Surely that includes a basic confidence check of the wet compass. We learned all about it to pass those exams, right?
At the point where it is too far out of whack to be good enough to get you home in an emergency - say 15 degrees - may be the time to call in the adjuster. Or DIY and don't say anything.....(just kidding, but again we did learn how to do it in theory).
But if it ain't broke, don't fix it.
To those who advocate blind obedience to CASA, try flying a typical golf ball wet compass to better than plus or minus 15 degrees in turbulence and let me know how you get on.

LeadSled 11th Jan 2015 03:58


So the CAA bureaucrats in New Zealand have also decided that they need to have more expensive regulations than the USA.
Particularly given the size and shape of NZ, where is is a bit hard to get lost. No GAFA equivalent in NZ

Tootle pip!!

Aussie Bob 11th Jan 2015 05:25


These people are very very clever, unfortunately much cleverer than us
Not clever at all Thorny, just corrupt and we let them get away with it.

If a rule is sensible I follow it, if I think its stupid I break it.

A compass swing on my aircraft is totally unnecessary. If it has a bubble I will fix it, if it is incorrect I will adjust it. If I think its stuffed I will replace it.

Arnold E 11th Jan 2015 07:10

Can I please ask a question, which I would like you to answer.

1) do you understand that the rules are written for the masses, not the legends that you people, clearly, are??

For the Americans, (Creampuff) you will notice I have only asked one question at a time, since I know it seems to confuse you Americans if there is more than one at a time.

scroogee 11th Jan 2015 08:10

"Particularly given the size and shape of NZ, where is is a bit hard to get lost." and yet people still manage it. We've also got or share of 'missing' aircraft- there's plenty of bush, forest, mountains and water to do the job.

Creampuff 11th Jan 2015 09:23

Arnold

Your question makes an assertion about the persons for whom rules are written, and asks whether I understand that the rules are written for those persons.

Your assertion is not completely accurate. But let's assume for a moment that it is.

The point of this thread is that the rules are an overkill, if the policy aim of those rules is safety.

Eventually Sunfish will confirm that the compass on his yacht does not have to be periodically calibrated by a licensed compass adjuster. Yet he managed to use that compass to navigate when all the electronic gizmos went haywire. How did that compass know that it was fitted to a yacht rather than an aircraft, and that it didn't have to be periodically calibrated by a licensed compass adjuster? How did it know?

Any mediocre pilot like me can manage to fly an aircraft safely from A to B, VFR, without a compass, an altimeter or ASI (or any GPSs or EFB). Any mediocre pilot like me can manage to fly an aircraft safely from A to B, VFR, and know how accurate the compass, altimeter and ASI are, and if I extend myself to the outer reaches of my intellectual capacity, I can work out if the Mode C info is accurate.

There's a reason for drawing those tracks, drift lines and distance markers on a map. There's a reason for those big white numbers on runways, and the runway magnetic alignment and elevation information in ERSA. The sun rises and sets in the same general directions each day. The pointers in the Southern Cross reliably do what those pointers do.

I'll say it for a third time: It's not about the desirability of serviceable and accurate instruments. It's about the presumption of innate incompetence and criminality of Australians, mixed with scaremongering that plays on the fears of ignorant punters, that has produced the regulatory Frankenstein destroying GA.

I'm unsurprised by the cognitive bias of punters that results in screams for more regulation, in the misguided belief that more and more rules will reduce the risk of the 30,000' death plunge. What is surprising to me is that people who should know better - those with considerable knowledge and experience in aviation - also succumb to, or worse - leverage off - cognitive bias, by calling for more and more regulation or trying to justify existing regulation that has been shown to have no material affect on safety (or worse, has been shown to have a negative impact on safety).

Arnold E 11th Jan 2015 09:32


trying to justify existing regulation that has been shown to have no material affect on safety (or worse, has been shown to have a negative impact on safety).
So read post 79 and answer me, do you think that such a situation could cause a problem? if not, then all is good in the world.:):)

evolved 11th Jan 2015 10:17

All the talk about unnecessary maitanence would have some merit if these checks were being done and no defects were being found. The facts are that defects are being found, serious ones at that. Isn't that the point of these test?

Arnold E 11th Jan 2015 10:42


altimeters are calibrated to within 100ft of actual.
WRONG.....read 100.5 and tell me what it says.:ugh:

Hasherucf 11th Jan 2015 11:50

Chinese altimeters are the worst, find many wont pass CAO 100.5 checks. Unfortunately they appear in many flight school Jabiru's or other RA-AUS training aircraft. AD/INST/39 covers a 12 month check instead of the CAO 100.5 24 month check.

Pure junk! proving you pay for what you get

Aussie Bob 11th Jan 2015 17:27

Arnold, the situation you talk about in #79 should be picked up by ay competent instructor. 5 knots in a lighty is a lot. Did the aeroplane float unnecessarily or did it bang onto the runway when rounded out? If, in your opinion, everytime something is "not right" in this world we need legislation, I feel sorry for you. The legislators couldn't write fast enough.


Can I please ask a question, which I would like you to answer.
1) do you understand that the rules are written for the masses, not the legends that you people, clearly, are??
By identifying "the masses" are you not making yourself one of "the legends"?

Creampuff 11th Jan 2015 19:32

The good news for you, Arnold, is that the Australian regulator is very happy to mandate as much periodic maintenance as you like.

Given the circumstances with which you have obvious concerns, I'd suggest you lobby for a prohibition on aircraft being used by pilots with fewer than - let's pluck - 100 hours' aeronautical experience, unless all of the flight instruments in the aircraft have been checked and calibrated by a licensed aircraft maintenance engineer in the previous - let's pluck - 6 months.

Stuff it: we're talking about safety here! Let's make it 200 hours in command minimum, and checks and calibrations every 3 months or 30 hours' TIS, whichever comes first.

The 'masses' in the USA can learn much about aviation safety from Australians.

thorn bird 11th Jan 2015 19:39

Jeez creamie!!
Bite your tongue!!

Oh dear, here comes another five hundred pages of new reg's.

Dexta 11th Jan 2015 22:46

WARNING!!! - Thread Drift...
 
I know all of the above has concerned VFR flight, and I know how useless most liquid filled compasses are, but WRT to IFR, other than the compass how can you re-align the DG in flight? And how picky is ATC with regard to your heading accuracy? I can understand getting a compass checked every 24 months for IFR, but as Mach E says, in the bumps you'd be lucky to get any better than 15 degree accuracy.

Squawk7700 12th Jan 2015 00:22

What your compass says is almost irrelevant to ATC.

If they need you to alter heading they will say "turn left 30 degrees."

You could have a compass 30 degrees off and it would not matter to them as they would rarely say "turn to heading 180," however if they did, they would soon follow with "turn right 30 degrees" once they realise your track didn't reflect the request.

I don't think I've ever heard of a bearing been given by ATC other than for traffic avoidance and even then it's usually just following eight points of the cardinals.

Arnold E 12th Jan 2015 00:25


Given the circumstances with which you have obvious concerns, I'd suggest you lobby for a prohibition on aircraft being used by pilots with fewer than - let's pluck - 100 hours' aeronautical experience, unless all of the flight instruments in the aircraft have been checked and calibrated by a licensed aircraft maintenance engineer in the previous - let's pluck - 6 months.
Do you believe that, that kind of response is sensible?
So its an easy answer which you still haven't done, in the circumstance in post 79, do you see any potential for a problem, yes or no?
Also, please give the exact quotation where I have said more legislation is necessary. I know that's 3 questions and I know your American, but try not to go into melt down.

By identifying "the masses" are you not making yourself one of "the legends"?
No

Creampuff 12th Jan 2015 02:25


Do you believe that, that kind of response is sensible?
On what basis have you determined that the current mandated periods are “sensible”, Arnold? Clearly not on the basis of an objective analysis of data and accident statistics from the single largest GA fleet on the planet.

Your question about the scenario in your post at #79 demonstrates the yawning gap that exists, in Australia, between decisions based on rational analysis of data and risk probabilities and consequences, and your gut feeling about the probabilities and consequences of a “potential problem”. Further, in true Australian style, the solution to the perceived problem is, as always, regulation.

You found an aircraft that had an ASI that over read by 7 knots, out of the factory. From that you extrapolate to the poor junior pilot glued to the ASI, stalling, spinning, crashing and burning. You say that the “skys are filled” with these people.

Oh the humanity.

For every example you can provide of some problem you’ve discovered “out of the factory”, I can provide an example of some problem I’ve discovered “out of the maintenance organisation”.

Perhaps we need more regulation and periodic audits of aircraft manufactures and maintenance organisations? Yes – that’s it. I think we should all be lobbying for more stringent training standards, more stringent recency requirements and more frequent audits of LAMEs and maintenance organisations by CASA. That will help make us safer, yes?

megan 12th Jan 2015 03:22

On 14 January 1962 James Knight commenced a flight from Ceduna, South Australia to Cook, South Australia in Wackett VH-BEC (ex-RAAF A3-139). He was never seen again. Over three years later, on 28 March 1965, VH-BEC was found by chance two hundred miles North of Cook. Knight had remained with the aircraft after it force-landed and inscribed a diary and his Last Will and Testament on the fuselage panels; the last diary entry was made on 20 January 1962. It was subsequently determined that the mount of the magnetic compass was loose and displayed headings that were 30 degrees in error.

Must be something in the water at Ceduna. Chap departed for a NVFR flight to Whyalla and ended up over Woomera due compass misreading - metallic object placed on glareshield, seem to recall it was the metal rings in the publications.

Beaufighter has an interesting note - Firing the 20mm guns causes a compass deviation. Deviation may be restored to the values on the compass card by firing a one second burst while flying level on compass north. This should be done at the first opportunity, and in any case before landing.

Arnold E 12th Jan 2015 03:28

I knew that would confuse you Creamie, 3 questions and not one answered.
If you believe that the scenario I gave would not present a potential problem, then ,hint, the answer is no, end of story. As for picking on factory aircraft, I'm not, it just so happens that the 2 I singled out were factory aircraft Did I suggest that that maintenance organisations don't make mistakes? (oops, another question.), well I'll answer that one for you, NO.


All the talk about unnecessary maitanence would have some merit if these checks were being done and no defects were being found. The facts are that defects are being found, serious ones at that. Isn't that the point of these test?
Seems to be fairly sensible to me.

Mach E Avelli 12th Jan 2015 04:49

Dick is absolutely right - regular compass swings are a waste of good money better spent elsewhere. Good gyros, for example. Or a backup GPS.

Those crazy Canucks flying close to the magnetic pole have never been able to rely on magnetic compass. In pre GPS days the drill was to align the DG with the runway before take off then reset it at approximately 15 minute intervals by calculating precession. In summer this could be assisted by using a pelorus, but in winter darkness a whole flight of several hours could be done simply by estimating precession and having a rough idea of which stars were what. Amazingly, even with limited ground Nav aids and all the nasty effects on NDB reception at those latitudes, pilots rarely got lost. Some of that classroom theory actually did have a purpose.

Which makes the point - pre GPS we could and did fly in some places without a compass, so surely we can live with one with a small air bubble in it, or a few degrees out. Just so long as we keep track of its errors.

The unfortunate loss of the Wacket on the Nullabor was not entirely due to compass error, though because the pilot was unaware of it, it certainly contributed.

Creampuff 12th Jan 2015 06:10

Getting out of bed in the morning creates “potential problems”, Arnold.

All the talk about unnecessary maitanence would have some merit if these checks were being done and no defects were being found. The facts are that defects are being found, serious ones at that. Isn't that the point of these test?

Arnold E: Seems to be fairly sensible to me.
I agree completely: It is ostensibly sensible.

Whether it is, in fact, sensible, is a related but different question.

What caused the defects? What objective risks did the defects create? What is the cost of dealing with that risk? Does that cost outweigh the potential consequences? Does the way of dealing with the risk cause more problems than it resolves?

For a maintainer, maintenance never causes defects. However, an objective analysis of the data shows that maintenance not only sometimes causes defects, but that more maintenance more often always causes more defects.

Maintainers don’t know – because they can’t know - what objective risks arise from an inaccurate compass, ASI or altimeter. It’s just assumed that because it’s mandated and defects are found, the risks must justify the mandate. It’s completely circular.

Megan: Pilots get lost with perfectly serviceable instruments providing perfectly accurate indications. What conclusions should we draw from that fact and the examples you provided?

Hasherucf 12th Jan 2015 07:30


For a maintainer, maintenance never causes defects. However, an objective analysis of the data shows that maintenance not only sometimes causes defects, but that more maintenance more often always causes more defects.

Can you point me to a study of this? So you are saying I shouldn't get my car serviced? Extraordinary claims require extraordinary evidence

Next time I see a compass without (read that nil) any fluid. Should I not touch it in case I create more issues ?


What caused the defects?
In my experience age , Storing aircraft outside in the sun , lack of use, rough operations. Not every aircraft is a cherished piece of machinery lucky to do its 100hrs annually with a single pilot. Most I work on fly there asses off, things break and wear.

An old operator once told me that you should leave a pilot with one aircraft. If you swap them around they find defects. If left they are accustomed to the faults they live with them. It is akin to a dripping tap in your house.

Psychology of pilots is fascinating. The Garmin trainer pointed out Pavlovian responses in pilots once . Since then I always chuckle when I see them displayed.

Creampuff 12th Jan 2015 09:17

Google "Waddington Effect".

Oracle1 12th Jan 2015 11:47

CAStApo vs Anarchy
 
As much as I believe that the CAStApo and their political masters are out of control, there a lot of people in this thread throwing out the baby with the bath water. The great majority of GA aircraft are tooling around the sky with primitive out of date technology that in my view is highly unreliable.

I have little to no sympathy for the uber rich whining about their operating costs on multi million dollar helicopters which by the way Eddy Dean I have never signed for a compass swing on and don't intend to. Only the foolish operate a machine with so many critical moving parts. Live in that world and pay the price. On a fixed wing aircraft (read sensible practical and RELATIVELY economical) I can achieve a compass swing within .5 of an hour with two mechanics or about $100 bucks, which in the big picture is small change. What the pilot does with that after he/she leaves is of zero interest to me.

The instruments should be calibrated just like a torque wrench or any other tool that we ask for a constant and predictable measure. This is a basic foundation in the science that has evolved into the ability to defy gravity safely. The ASI, Altimeter and VSI provide information far more critical than the compass. I am firmly with Hasherufc and Arnold E on this one and I am somewhat bemused that the more learned among us are effectively promoting anarchy on the instrument panel as a method of questioning the CAStApo's regulatory shortcomings.

Gentleman, your effort would be better spent questioning why the whole country is going down the gurgler or why aviation is an ever increasing extortion racket. The CAStApo are a symptom not the cause. Unless the battle is fought on a political level you will continue to suffer from bizzare regulatory conditions, far removed from and infinitely more toxic than a simple instrument calibration.

Hasherucf 12th Jan 2015 12:08

So Creampuff I spent about 2 hours researching researching the "Waddington Effect" and honestly I didn't find much. Most seems to come back to AOPA pages and Sports Aviation Webpages. The same article Written by Mike Busch.

EAA Sport Aviation - March 2011
EAA Sport Aviation - March 2011

and this article which is half plagiarised from wikipedia

The Waddington Effect « Opinion Leaders

http://cmapspublic.ihmc.us/rid=1HTKPYHY3-10D9MZ0-11ML/
Mike seems to have got his idea for this piece from a little history lesson article by Dr James Ignizio from the University of Texas. Dr James doesn't seem to any citations expect this paper

C. H. Waddington. "O. R. in World War 2: Operational Research against the U-boat", Elek Science, London, 1973.

Where its claimed that submarines are 20% less visible if painted white. Strangely they are still black now.

Wikipeda doesn't offer any clue to his CH Wallington war time activity's.

A Book : Cognitive Biology: Dealing with Information from Bacteria to Minds
By Gennaro Auletta
Refers to the WaddingTon effect in Biological terms


The major claim seems to be:


Once these recommendations were implemented, the number of effective flying hours of the RAF Coastal Command bomber fleet increased by 60 percent!
Of course this could be true but be careful with cause and effect..

So the only modern (post 1970's) reference I could find was in a MIT paper. Unfortunately the context of the paper is unclear.

http://ocw.mit.edu/courses/engineeri...event_main.pdf


It states "Impact of Waddington Effect = 1.4% Availability"

So your statement of

For a maintainer, maintenance never causes defects. However, an objective analysis of the data shows that maintenance not only sometimes causes defects, but that more maintenance more often always causes more defects.
seems nonsensical if it affects availability by 1.4%.

I wanted to find more. Hard facts!! But we are comparing a wartime environment to a Sigma Six environment. Many people in the war time environment would have been trained in a rush and working in adverse conditions. Now we have rules for maintenance hangars.

Okay that was thread drift but interesting bit of reading :)

dubbleyew eight 12th Jan 2015 12:30

although I rarely use them I check my instruments every flight.

the altimeter is set to airfield height by tweaking the QNH.
after a flight typically for an hour or more and altitudes up to 6000ft I return and land. the altimeter on the taxy back is reading the airfield height.
I'd say it was working satisfactorily.

occasionally I check my stall speed. 42 knots indicated. bang on the money every time. now I know that there is a 10 knot instrument setup error and I am actually stalling at 52 knots but that doesn't matter. I fly circuit speeds on the indicated speeds. in cruise I use a gps anyway. at 120 knots the error is 1 knot.

I never use my magnetic compass ever. I check it on the lineup every few months and if the leg is long and the air stable I compare it to the gps.
it hasn't been out in over 10 years.

to assume that aircraft are being flown with wildly inaccurate and never checked instruments is nonsense. they get checked all the time by pilots.
one of the things never mentioned in the race to deride old technology is that aircraft instruments are of the highest quality ever made. they are not shonky items. why would an instrument made to such quality go out of adjustment?
mine don't.

the wackett fatality had nothing to do with the compass in reality.
the pilot assumed that he would see the transcontinental railway line and be able to turn for forrest.
I took a photo on one of my flights in the position where he crossed the railway.
in the afternoon light, even when you know where the railway is, it is impossible to see it. a salutary warning for pilots flying pilotage in the gafa.
the gravel ballast is the same colour as the surrounds and the actual rails are only 4 inches wide. unless you get the shine on the rails they are invisible.

LeadSled 12th Jan 2015 13:12


So Creampuff I spent about 2 hours researching researching the "Waddington Effect" and honestly I didn't find much.
Hasheretc,
Must try harder.

The RAF discovered that continually fixing things that ain't broke quite severely reduced aircraft availability, and significantly, maintenance induced defects were a major contributor.

What the RAF discovered, refined and developed over the years, we would now call "on condition" maintenance.

The nearest Qantas ever came to losing an aircraft in flight (and I am thinking of two serious incidents, one a DC-4, the other a B707-338C) were maintenance error defects.

"Back in the day" I have taken quite a few aircraft on their first trip "out of the hangar". You expect to find defects, and are seldom disappointed. Some were really serious, ( keepers left off aileron pulleys, cable came off the pulley, as just one example, I could go on. Those of us with enough time under our belt all know that the first 10 hours "out of the shed" after a major inspection can be very interesting.

The whole point of what Dick and Creamie are saying is that much of the approach to GA maintenance in Australia allows little room for common sense, the framework of the law makes us all criminals, just some of us haven't been caught yet. And it maximizes cost, for no safety benefit, let alone a positive benefit/cost.

It is almost never "evidence based" maintenance.

Tootle pip!!

PS: Anybody remember the CASA rules for compass swinging about 2003, that were rapidly dropped? This was "how to do it", not "when to do it". The first "concession" was for the QF B747 and B767, a big enough compass base didn't exist, anywhere in the world, to do what CASA proposed to impose. The clown who wrote the CAO had never heard of a landing compass, and the order was substantially about building a compass base with brass plugs around the perimeter, surveyed to denote the cardinal points. Perhaps the most absurd, of many absurd things produced by CASA over the years.

Creampuff 12th Jan 2015 19:28

So I think you have your answer, Dick.

A country whose GA fleet is mere rounding errors on the size and hours amassed in the USA knows better. You should feel comforted by the fact that your helicopter will be 'safer' in Australia. :ok:

If you fly your helicopter past the date on which the compass has to be calibrated, without having it calibrated, you'd be a dangerous criminal even if it remained accurate. However, if the calibrated compass suffered a random failure in flight, you're safe because the compass had been calibrated.

You see: It's all about 'safety'.

Hasherucf 12th Jan 2015 23:29


The RAF discovered that continually fixing things that ain't broke quite severely reduced aircraft availability, and significantly, maintenance induced defects were a major contributor.

What the RAF discovered, refined and developed over the years, we would now call "on condition" maintenance.
You quoted much of what AOPA had to say. Please send me a link to the original "Waddington Effect" paper. It seems people have hijacked/indoctrinated the term "Waddington effect" from C.H Waddingtons biological paper in a fallacy from authority attempt.





The nearest Qantas ever came to losing an aircraft in flight (and I am thinking of two serious incidents, one a DC-4, the other a B707-338C) were maintenance error defects.
Yes errors happen in maintenance and they are attributable to accidents and incidents. But it's a small percentage. I believe pilots are the largest and then ATC , weather , maintenance etc.


"Back in the day" I have taken quite a few aircraft on their first trip "out of the hangar". You expect to find defects, and are seldom disappointed. Some were really serious, ( keepers left off aileron pulleys, cable came off the pulley, as just one example, I could go on. Those of us with enough time under our belt all know that the first 10 hours "out of the shed" after a major inspection can be very interesting.
That is a personal anecdote , how does it relate to a study?

I really think you are comparing apples with oranges on the study. To which I am yet to find the original attributable source. In the book "The Ravens" it is mentioned that the Cessna Birddogs were unreliable. Until command changed from B-52 engineers to engineers who had worked on type. Could it just be that in 1941 they didn't have enough trained staff to service aircraft ??

c100driver 12th Jan 2015 23:52

Reliability Centered Maintenance
 
As a former aircraft engineer, current pilot and aircraft owner I am firmly with Creampuff on this one.

More damage has been done to my Cessna by engineers pulling it apart to do inspections than has been found by the inspections.

RCM is what should be used and in a way has been in Schedule 5 however that was based on post war aircraft not on later american manufactured machines.

The key with RCM is continuous review. There is a lot of scientific literature on the use of RCM to manage complex systems.

Arnold E 12th Jan 2015 23:55


the altimeter is set to airfield height by tweaking the QNH.
after a flight typically for an hour or more and altitudes up to 6000ft I return and land. the altimeter on the taxy back is reading the airfield height.
The ONLY thing that tells you is that the instrument has little or no hysteresis.:ugh:

aroa 13th Jan 2015 03:33

Interesting read..
 
Flight into Nowhere. regarding the lost Wackett tragedy.

Apart from not spotting the iron rail..due visiblity or being well before expected eta for intercept time, due to the compass error, he ploughed on.

And the error was caused by; vibrating loose during the journey from Melbourne or some magnetic item interfering. The booklet states there was a reading difference in the cockpit compasses installed...so when he collected the aircraft, either not noted and rectified or the problem developed en route.

Flying on well past expectation of the rail sighting and not being able to return, put the poor guy into some of the worst country imaginable in the central gafa.

The huge search was done twice over the same area. Did anyone think out side the square and extend the block...alas, apparently not. And he wasn't that far from the NE corner. Vale James Knight

In those days compass (heading) clock, map, measuring stick and pencil was all there was.
Not so today. Have a look at the GPS..it says the destination is that way, xxxx miles away, and it will take you x hours and yy mins to get there.. too
easy. Until the power goes off !
Aah do love those paper maps, as one from the old school.

The compass importance just aint what it used to be, with all the alternative techo, of reliability and great accuracy in use today.:ok:

Wackett BEC recovered with some difficulty, resides in the Central Australian Air Museum, Alice Springs.

no_one 13th Jan 2015 04:35

Imagine new aircraft instrument was invented. It only told you which way you were facing not the direction you were going. Relative to a grid system that varies over the earth, as long as you are not turning, climbing, or accelerating. The placement of other things near it rendered its readings useless and could be affected by the currents when other equipment was turned off and on. Would you pay good money to have it installed in your aircraft?

...makes me wonder why a compass is a required instrument and a GPS is not.

Fantome 13th Jan 2015 06:59

Once upon a time a seasoned old LAME looked at the compass in an aged but still absolutely serviceable aeroplane. Rubbing his chin, he pointed to the inoffensive little P9 and said . . .. "All you can say with certainty about that little number. . . . she'll tell you every time when you're pointing straight ahead."

dubbleyew eight 13th Jan 2015 09:07


The ONLY thing that tells you is that the instrument has little or no hysteresis.
if the altimeter had never been calibrated you might be correct.

it is a calibrated instrument and is behaving exactly as expected.
hence it is probably still functioning within the 100ft allowance for a vfr altimeter.
...and it has no hysteresis.

It does me.

Arnold E 13th Jan 2015 09:10


for a vfr altimeter.
VFR / IFR same requirements.


it is a calibrated instrument
When was thee last time ?

Hasherucf 13th Jan 2015 09:37

Arnold E you are an instrument tech , explain me the "100ft allowance check" ??


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