CASA $1,000 Useless Compass Check

[Dick Smith]

Readers of this site may remember years ago when I complained about AD Instrument 8 which was an Airworthiness Directive that required routine checks on things like the airspeed indicator, the compass and the fuel gauge.

I started a campaign to remove this AD and it was agreed by CASA that only items required in other leading aviation countries would be put over to a CAO.

CASA issued a Notice of Proposed Rule Making and from what I can remember it had lots of submissions from the avionics industry that makes money from these ridiculous checks.

I understand we now have CAO 100.5 which results in some of the most onerous and expensive checks in the world, including every twenty-four months a compass check on privately-registered helicopters.

You can’t just tow a helicopter to do a compass check – you actually have to hover it. What if you had to pay a pilot to travel to the maintenance hangar to fly the helicopter to do the compass checks? The overall cost is about $1,000 and this has to be done every twenty-four months.

Of course, every time I taxi along the taxiway at Bankstown I know the exact compass heading and I can tell if the compass is faulty or not. So the $1,000 is a complete misallocation of money – other than for the maintenance industry who no doubt makes a fortune from it.

It also appears we have a forty-eighth month fuel gauge check.

Neither of these checks is required in the USA for privately registered aircraft.

I would like to hear other comments in relation to this.

Remember – if your aircraft happens to be in Birdsville and it is not concurrent with a one-yearly maintenance check, it could mean flying the aircraft to Adelaide or Longreach to have the check done. Imagine the cost!

[Jabawocky]

Dick,

Do a search on 100.5 and you will find much bleating. A year or so back :ok:

The intent is great….the implementation is a disaster. Like some of the rude letters they send out to owners telling them that their SIL=0 broadcasts by their transponders may be correct, but they need top get it fixed before further flight or possibly face further action.

What moron wrote that? in the first instance what they are reporting is correct, they then say that it may well be correct, then they say fix it or else.

The place is a disgrace. If this was an isolated case of poor written communication, I would let it slide, but seriously these guys have lost the plot on so many fronts I have lost all hope in ever seeing improvement.

So what hope have you of getting sense on 100.5, and what is worse some avionics shops have some very weir interpretations of many things of late. And they are not always correct.

Good luck.

[Arnold E]

Of course, every time I taxi along the taxiway at Bankstown I know the exact compass heading and I can tell if the compass is faulty or not

Rubbish, to start with it only tells you what is happening on that particular heading, do you honestly believe that just because a heading is correct in one direction that it is also correct on all headings? Also how do you know your axis is perfectly aligned with the taxiway. Believe me, I am no great lover of CASA, but after having done a "few" 100.5's I can tell you that there is more than one aircraft with fuel gauges that read in bananas and more critically, many ASI's that read elephants, coz they certainly don't measure Knots. :=

As I have said, I am no great lover of CASA, but I reckon this is one of the few things that they have done that is a good thing

Static leaks,,,,,,,,,dont get me started

[Dick Smith]

Different taxi ways at different times. Surely that is clear.

Arnold. How come other countries don't reqire these expensive rules?

Resultant safety levels in the USA show that we should not be mis allocating this money.

[Squawk7700]

I can't even remember the last time I even looked at my compass.

A $1,000 check on a potentially $100 item is beyond ridiculous for the owner.

[Hasherucf]

I'm with Arnold E. Static + Pitot leaks mostly in VFR registered ****boxes. God damn I have spent days under dashes chasing leaks Eventually I came to the realisation that it's easier and less time consuming to change the whole static system in something like a Cessna 172.

I've found the static system open to atmosphere , Bolts stuck in the end on pipes and silastic up . Pipes completely missing, mud wasp nests ,chaffs and sun affected pipes etc.

VFR LAMEs have just been ticking boxes for a long time. Probably back to the days of when CAO 108.56 went extinct.

As for compasses most seem to have more air than fluid.

All over I think 100.5 has brought up the standard of aircraft. I get paid a wage either way and don't profit any extra from the additional work. My chiropractor might profit more as I'm breaking my back under a dash.

[Arnold E]

Hang about, lets be realistic here, a compass swing does not cost $1000. If its costing you that much, contact me.
When did 100.5 include a compass swing?

[Eyrie]

Completely agree with you, Dick. Useless regulation for its own sake. Have you seen the justification for 100.5? Doesn't even talk about safety, just a nice to have arm waving statement.
More Eurocrap regulation for its own sake where VFR aircraft are treated like IFR, increasing costs for no safety benefit.
Let's go to the Canadian owner maintenance category for private aircraft owners who wish it. The resultant standard of the fleet is likely to rise, not because LAMEs do a bad job, because the owners themselves will fix problems when they become evident, not when maintenance is scheduled.
I've no objection to the old instrument 8/rad 47 as the altimeter, transponder and static system are where everyone interacts with the system.
If you LAMEs are finding static leaks now, why weren't you finding and fixing them under the old system?

[Eyrie]

maybe you should read 100.5 before looking ignorant in print.

[Dick Smith]

Arnold.

I keep my Jetranger under the bedroom at my home at Terrey Hills.

How would you do the compass swing at less than $1k?

[tipsy2]

Reminds me of the mental midget AWI that demanded a "Remove Before Flight" placard on the INSIDE of my Airtourer canopy cover.

Tipsy

[Arnold E]

maybe you should read 100.5 before looking ignorant in prin

Yeah ok, but not in the specific amendment alluded to.

[Arnold E]

I keep my Jetranger under the bedroom at my home at Terrey Hills.

How would you do the compass swing at less than $1k?

Ok you win.:)

[Hasherucf]

Eyrie you ever looked under the dash of the average cockys aircraft dash?. They want the cheapest price on a service and the LAME's in the past complied. Now the avionics side got involved we actually did the tests and they come up short.

[Arnold E]

Eyrie you ever looked under the dash of the average cockys aircraft dash?.

And the ever increasing number of home builts.:eek:

[Hasherucf]

Yeah Arnold E , If homebuilders could not use nyloc nuts to put in aircraft instruments that would be great. We have these things called instruments nuts now days. Saves about half hour taking out instruments. Or even cherry rivets to hold in radio racks, even better a certain factory build Czech aircraft that silastics the entire transponder rack in (no hardware). Or a home builder that used household electrical joiners through out his audio panel install.


:ugh: I will never be out of a job it seems

[Squawk7700]

I watched a Sikorsky S76 doing a compass swing only a couple of weeks back. At $100 a minute it was not a cheap exercise.

[Arnold E]

, even better a certain factory build Czech aircraft that silastics the entire transponder rack in (no hardware).

Or the high wing plastic Oz built factory aircraft with the encoder plummed to the pitot line.:{

[Jabawocky]

I will bet that had an outstanding ROC on the radar screen :}

[Arnold E]

I will bet that had an outstanding ROC on the radar screen

Actually ROD (well both actually), but as it happens he never went into controlled airspace so no one ever noticed, well atc must have noticed due to the negative altitude but they never said anything to him.

[Username here]

I keep my Jetranger under the bedroom at my home at Terrey Hills
How would you do the compass swing at less than $1k?


I really wish I could feel sorry for your plight Dick. I really do.

Having a jet ranger under your bedroom is s luxury... If you can't afford it - sell it.

[27/09]

24 monthly radio and instrument check, nothing that doesn't get done in other parts of the world.

If you're going to operate in controlled airspace VFR or IFR then this stuff needs to be working to some known level of accuracy or standard.

[Radix]

..........

[Dick Smith]

I propose we copy other proven safe procedures from leading aviation countries if they result savings in expenditure.

If we don't we will further destroy our aviation industry.

Yes. I can afford the waste. But I am concerned about most in the industry who can't

[Dick Smith]

27/09. You are incorrect. Other leading aviation countries such as NZ , Canada and the U.S. do not have such money wasting requirements . I have checked!

[Creampuff]

Which may be a good thing or may be a bad thing.And the safety record of the single largest GA fleet on the planet, operating in less benign weather and geographic environments than the Australian fleet, provides the objective answer.

But as Australians cannot be trusted to exercise independent judgment or take individual responsibility to deal with these extraordinarily complex technical and risk issues, it's necessary to makes thousands of pages of rules to ensure that society is saved from individual Australian's innate incompetence and criminality. Give me strength ... :ugh:

I agree wholeheartedly with Dick's point on this one.

[Arnold E]

Ok, lets concede the compass, (assuming it hasn't leaked fluid or changes made to the aircraft), What about the other checks in the 100.5 amendment, do you think that they are not worthwhile as well. ASI's and altimeters last forever, for instance? Fuel gauges always accurate? Encoders never change? Static systems never deteriorate?

[Progressive]

NZ compass calibration requirements covered under Civil Aviation Rule 91.605(e) (5). And AC43-7 which lists the acceptable means of compliance as - 2 years

Canadian compass swing required under CAR standard 625 appendix C point 10 - 1 year

FAA - fairly typically no guidance provided HOWEVER aircraft is required to be in compliance with its type certification standard at completion of the annual inspection and type certification requirements FAR3, FAR23, require the compass to be accurate with errors of no more than 10 degrees. So technically annual should include a compass check - if not a full calibration.

So sorry dick but 27/09 has this one on the money.

It has occurred to me that the difference in compass swing requirements is more to do with the lack of navigational coverage in AUS as compared to the USA. WE have quite a few remote areas where 3 degrees of track can mean a long way from your destination. With little help from ATC

[rutan around]

Having a jet ranger under your bedroom is s luxury... If you can't afford it - sell it. This statement is idiotic. Dick and others are wealthy because they don't spend their money stupidly. Just because you can afford to pay say $25 for a can of coke would you?

The problem is, unlike the can of coke,you can't just walk away from deal. If you want to keep flying you have to comply with every CASA solution to non existent problems.

We need a strong union to peer review all new rules or better still force the adoption of FAA rules.

What's a pissant country like Australia flying mostly American aircraft doing wasting millions and millions of dollars inventing it's own inferior system?:ugh:

[Dick Smith]

Progressive. You are misreading the NZ and canadian regs. They are not as prescriptive as that

Do you work for CASA?

Rutan. Your last sentence is the best I have read on pprune for years. Can I quote it to the PM?

[thunderbird five]

The word "compass" does not appear in CAO 100.5. So no checks required - by that CAO. So let's look elsewhere.

"Compass" does appear in AWB 34-008, but an AWB is not a regulation or an order, it's just advisory. CASA often tries to, but in reality, cannot demand things which are not mandated by regulation or order.

Does "compass checking" withstand the simple test: "show me where it says in the regulations that it needs testing."

It used to be in the old CAO 108.6, which got repealed in 2007, same time as AWB 34-008 hit the newsstands.

I suspect that it is just old wives tales regurgitated again and again by who knows, maybe poor LAMEs who can't keep up with the ever moving goal posts (regs) that keeps the compass checking BS alive and prosperou$ Dick. I'm with you on this one, it's pure BS. Sure - get it done if you notice a fault.

I also cringe whenever I hear LAMEs and others refer to CAR 35 engineers. THERE'S NO SUCH REGULATION 35! Hasn't been for years.

Hope this helps the battle Dick. I think we are out gunned by Fort Fumble. It's sad.:(


I also ask friends in USA this: "when, if ever, do you get your VFR aircraft instruments checked?" - NEVER.

[Arnold E]

I also ask friends in USA this: "when, if ever, do you get your VFR aircraft instruments checked?" - NEVER.

That being the case, why bother to have them at all if what they may be telling you is nonsense?

[Hasherucf]

You're right Thunder Bird Five is only suggested that it's carried out every two years. If they are travelling well from the last overhaul then I don't do swing them.

If the compass has been done in a vacuum chamber at last overhaul normally they go 4 years.

Of course if they have had a engine change or major electrical change then we would do them. I don't know what Dicks situation was.

I still call them CAR 35 , Even now its called Part 21M. Force of habit I guess.

:}

[Creampuff]

As usual, the debate disintegrates into the conflation of the "what maintenance should be done" argument with the "when and who should do it" argument.

Let's approach both arguments in a different way.

Who'd be prepared to fly a light aircraft with a dead compass, dead fuel gauges and a dead ASI?

Me, for one, if I had sufficient knowledge of the particular aircraft's systems.

This is the difference between being a piano tuner and a piano player.

Someone very close to me is lobbying to get rid of magnetic north, completely, in aviation navigation. For good reason.

If the 6 or so GPSs, my eyeballs and the map on board my aircraft disagree with the compass, I'm opting for the 6 or so GPSs, my eyeballs and the map, rather than the compass. On the one in a zillion chance that the 6 or so GPSs, my eyeballs and the map are misleading and the compass is correct, I'm lost. Oh dear.

But that will happen less often than the compass becoming wonky in between periodic, certified servicings.

I realise that some will be comforted by the fact that in the latter case I will have become 'legally' lost, as a consequence of a fully certified and fully maintained piece of 18th century equipment suffering a random failure, but that's not quite the point if you're worried about safety...

Who's silly enough to trust fuel gauges in a light aircraft? A common failure mode in the kind of aircraft I regularly fly is fuel gauges reading 'FULL' constantly, because of a fuel bladder being sucked up against the sender. To be safe(st), pilots need understand and be able to spot the typical circumstances in which fuel gauges maintained and certified in accordance with the rules are lying, rather than assume that periodically maintained and certified systems must be OK.

If I take off with tanks that I know are full (this requires aircraft and systems knowledge) but gauges reading 'EMPTY', and I know I have a fuel totalizer designed after the 1950s and calibrated to 0.1 of a litre in hundreds of litres, I'm comfortable that I can conduct a lengthy flight and predict, within a tolerance of +/- 2 litres, how much fuel will be needed to fill the tanks at the end. I'll have to have a clever procedure to confirm fuel isn't venting at a high rate from an unsecured cap or drain, though.

If you bother to look at all of the fuel exhaustion accident reports, the vast majority involve aircraft that had perfectly serviceable fuel gauges. Again, I realise that some will be comforted by the fact that the fuel gauges on these aircraft were certified serviceable and telling the pilot that the motion lotion was about to run out, and then it did, but that's not quite the point if you're worried about safety...

The control column is an ASI. Ask aerobatic pilots why this is so.

The most recent 'real life' static system problem of which I am aware was caused by a maintenance problem: some engineer had reconnected the static lines, incorrectly, to the alternative static source valve.

Don't get me wrong: I'd prefer to have an ASI and other instruments and gauges that are working perfectly. The flight's usually a little less stressful if all the knobs and dials are in eye-pleasing positions.

But this discussion is not about - or shouldn't be hijacked into a discussion about - the principle of whether it's safe(r) to have all these things working. The discussion is about whether the suite of regulations requiring periodic inspections and certifications by licensed aircraft engineers is necessary, in practice, to produce sufficiently reliable systems. That question has been answered, based on statistically valid data, elsewhere.

Unfortunately, Australian's innate incompetence and criminality results in the rejection of that answer as acceptable and implementable in the Australian context.

Apparently it's all OK because you can afford it, Dick....

[Jabawocky]

Rutan and Creamie POTY award contenders for sure. :Dx2

Dick….I am with you on this one. :ok:

Did you find through the search function a heap of history?

[dubbleyew eight]

I used to have my instruments checked every two or three years but it was a waste of time.

altimeters are calibrated to within 100ft of actual.

I could never understand why my altimeter on the ground never matched the QNH settings of others. they were calibrated but they never ever agreed.
so I came to the opinion that aviation instruments were crap.
as a surveyor I am well accustomed to calibrated precision instruments.
one day I was collecting my recalibrated instruments.
the guy (lacewing) said thank god you've turned up. you were the last customer and now I can retire. thank fcuk for that.
as I took the instruments out the door he shared with me this little gem...
"you homebuilt guys haven't got a hope you know. I always calibrate your instruments so that no matter how well you fly you always appear in the circuit at the wrong height."
why I asked.
"got to maintain the need for a certified environment you know".

well as the years have rolled by since I now have 5 altimeters.
I also have access to the kollsman instrument adjustment manual.
I adjusted all my altimeters sitting beside an IFR certified instrument (sitting on the ground in the copilots seat one day.)
only since I have adjusted them do I have 5 instruments that always agree within the 100ft tolerance.

Dick, even when you do get them calibrated, you can't trust the work done.

I swing my own compass. it isn't hard to do.
they are only accurate to 5 degrees. they aren't marked any finer than that unless you have a tiger moth P2 style compass.
you really only need to work on the compass if the rotation of the card becomes erratic due to the peening out of true of the tapered pivot post.
or they develop a leak.
havent had a problem with mine in a decade. it is tucked away out of the heat at the bottom of the panel which helps.

calibrations are yet another set of sensible ideas developed to idiocy.
W8

[rutan around]

Rutan and Creamie POTY award contenders for sure.Jeez Jabba it's only the 8th Jan. I'm sure Creamy and certainly I wish you'd posted that 9 days ago.:E:E

[Radix]

..........

[50 50]

Fuel gauges? Why has no one mentioned the fact that we use a dipstick, every flight, because fuel gauges are about as accurate as news reporting?

It's a foolhardy pilot that trusts a fuel gauge without dipping the tank. Properly certified or not.

[27/09]

Dick SmithProgressive. You are misreading the NZ and canadian regs. They are not as prescriptive as that


Dick I cannot talk about the Canadian Regs, but I can for the NZ ones and the 24 month inspection is not optional it is mandatory. Every NZ registered aircraft has a compass calibration sticker near the compass or on the panel which has an expiry date. It has to be renewed every 24 months.

I'm sorry your information on this issue is incorrect.

[Dick Smith]

Thunderbird. You say the compass check is not required under the regulation however my maintenance provider says it is.

I use John Cameron Aviation at Bankstown. I have always found them reputable.

Can anyone throw more light on the requirement ?

[Eddie Dean]

Hi Dick
Compass swing is two yearly mandatory requirement.
I would listen to the folk at JC Aviation, they are very reputable.

[scroogee]

Though I believe there is some tolerance in the NZ rules allowing the compass swing (and some other checks) to be deferred for a defined period of time to align with other mandatory maintenance.

[27/09]

Though I believe there is some tolerance in the NZ rules allowing the compass swing (and some other checks) to be deferred for a defined period of time to align with other mandatory maintenance.

Yes there can be a 10% tolerance have it done 10% before or after. The 10% can be airframe or calendar depending on which method is used for determining the maintenance period.

[Dick Smith]

So the CAA bureaucrats in New Zealand have also decided that they need to have more expensive regulations than the USA.

Those stupid Americans. How did they ever get to the moon. Must have been a fluke.

[Draggertail]

AIRWORTHINESS BULLETIN AWB 34-008 Issue : 1 Calibration of Compasses Date : 22 January 2007
Applicability
1.1 This Airworthiness Bulletin (AWB) is applicable to all aircraft and is intended to assist with calibrating and compensating aircraft magnetic compasses and provides data on the maximum allowable deviations enabling the compass to be maintained to its type design.
2.1 The objective of this AWB is to establish the minimum standard of maintenance considered necessary to ensure the accuracy of an aircraft compass system.
2.2 This AWB provides information for the calibration of direct reading and remote reading magnetic compasses. Alternative standards may be used provided they can demonstrate an equivalent level of safety.


There is no mention of compass in CAO100.5. CASA schedule 5 only mentions a compass inspection. The AWB above says 24 monthly calibration should be carried out.


So, Dick, para 2.2 gives you an out. Just demonstrate the equivalent level of safety given by the US system and tell your maintenance organization to stop doing the calibrations.

[Arnold E]

Those stupid Americans. How did they ever get to the moon. Must have been a fluke.

I am sure it was Dick

Why is everybody fixated on the compass, what about the other parts of 100.5 :confused:

[Slippery_Pete]

The ridiculous thing is the calibration card will say "pitot heat on" or some such.

And yet the majority of VFR aircraft flying around have it switched off.

Next thing we know, CASA FOIs will be ensuring that pilots are turning on the pitot heat momentarily to get an accurate reading from the compass.

Idiots.

If the compass is unreliable or has bubbles or isn't accurate, pilot endorses the MR and it gets fixed. End of story.

Will CASA not be satisfied until there's no GA aircraft left in Australia?

[Arnold E]

So Dick, when we find ourselves coming in to the same uncontrolled airport, me in my quite fast, (I think) RV7 and you in what ever you choose to be flying that particular day, you are more than happy for me to be coming from a direction that I am not sure of. at an altitude that I have no idea of, and at a speed that could be anything. (Now I don't want you winging of my incorrect estimate of arrival.) Cant wait to meet you at that airport Dick :ugh:

pilot endorses the MR and it gets fixed. End of story.


Now that has to be one of the funniest things I have EVER read on PPrune. That is a stupid statement. Ask ANY LAME about how many faults are actually written up. HaHaHa.......

[Flying Binghi]

Hmmm... perhaps if Mr smith thinks a compass calibration is a pointless rort and a waste of money he should just think of it as a 'compass tax' and he will feel all goodly about it... sorta like the pointless waste of money carbon tax he spruiks..:)

Dick Smith: I Was Gutless Over Carbon Tax Ads (http://www.smh.com.au/environment/climate-change/i-was-gutless-over-climate-ads-dick-smith-20110530-1fbwk.html)











.

[Creampuff]

coming from a direction that I am not sure of. at an altitude that I have no idea of, and at a speed that could be anything. (Now I don't want you winging of my incorrect estimate of arrival.) Blatant hyperbole. Spoken like a true scaremonger. It's folks like you that GA in Australia can thank for thousands of pages of regs, tens of thousands of pages of CAOs and the same in MOSs.

You can't work out your orientation to an aerodrome without a calibrated compass? Really?

No idea of altitude? Really? No idea?

At a speed that could be anything? Really? Anything?

Please: Save us, CASA. We need more laws to prevent this from happening. :rolleyes:

[BlatantLiar]

Now that has to be one of the funniest things I have EVER read on PPRuNe. That is a stupid statement. Ask ANY LAME about how many faults are actually written up. HaHaHa.......

Shows how much some of the people actually operating the aircraft care if something works or not.

[Arnold E]

You can't work out your orientation to an aerodrome without a calibrated compass? Really?

No idea of altitude? Really? No idea?

At a speed that could be anything? Really? Anything?

I hear you Creampuff, but I am appropriately licensed to fly my aircraft and I could be at an airport near you, ( Ok not near you coz you are awsome) but I could be near Dick. The point is not everybody is as awesome as you flying without instruments.
Also, if you took that literally, then you are truly, shall we say, strange.

[50 50]

Oh come on, if you're not using a GPS, or an Ipad with Ozrunways or Nav plan, or some other program, or a hand held GPS, then you're relying on century old technology.

It's a fundamental skill I'm told. So is fire starting, but who doesn't use a lighter or match? I can walk where I'm going, but why would I? I can drive! Everyone pretends they are some type of navigational God, deftly calculating ETA against airspeed, ground speed, and skin friction. But that's crap.

Old style navigation is stressful, needlessly difficult today, and one stands an excellent chance of getting lost. Before everyone decries falling standards and crap training, let me volunteer, the training I paid good money for was crap, and my navigation is Sh!it. Not because I want it to be, but a perfect compass won't help at all.

[Hasherucf]

Talking with a CASA guy a few years back they were hoping to include Compasses in CAO 100.5 . Until then it was in an AWB.

An Airworthiness Bulletin (AWB) is issued to inform the aviation public, in a systematic way, of essential information not considered mandatory.

CAO 100.6 was repealed in 2007.

So why mandatory every two years? . Surely if servicable you would just use until proven defective. Unless dictated by manufacturer or SOM

Happy to be proven wrong

[Arnold E]

Surely if servicable you would just use until proven defective.

Err, How do you do that???

[Slippery_Pete]

Now that has to be one of the funniest things I have EVER read on PPRuNe. That is a stupid statement. Ask ANY LAME about how many faults are actually written up. HaHaHa

So get CASA to save aircraft owners like Dick Smith these ridiculous costs, and instead get them to spend their time and money on enforcing the penalties on pilots for not recording aircraft defects.

Those pilots you refer to are wilfully breaking the law.

Perhaps if that culture didn't exist, there wouldn't be ridiculous inspection costs on aircraft owners.

In fact, if it weren't for CASA and these ridiculous expenses, perhaps aircraft owners could afford a new aircraft and their 40 year old c172 could be sent to the scrap heap where it belongs.

[thunderbird five]

I just report the facts.
Fact 1: "Compass" does not get a mention in CAO 100.5. This CAO is where all other instrument checks get a mention.
Fact 2. CAO 108.6 regarding compass calibration was repealed (cancelled) in 2007.
Civil Aviation Order 108.6 Repeal Order 2007 (http://www.comlaw.gov.au/Details/F2007L04869/Explanatory%20Statement/Text)
which says "The Order is repealed as it is no longer required."
Fact 3. AWB 34-008 came in in 2007 and, while describing in good detail, what a compass calibration should be, is not a regulation or an order, it is advisory.
Fact 4 to support fact 3:
Civil Aviation Safety Authority - Airworthiness bulletins (http://www.casa.gov.au/SCRIPTS/NC.DLL?WCMS:STANDARD::pc=PC_90516)
An Airworthiness Bulletin (AWB) is issued to inform the aviation public, in a systematic way, of essential information not considered mandatory.

So CASA deliberately moved compass checks from mandatory to advisory, in 2007.

I'd suggest if any maintenance facility, or anyone for that matter, is stating categorically that something is mandatory, that's fine, just politely ask them to educate you, and show you where it says that in the regs. (Then go check if that reg still exists!)

My point is, don't believe everything you are told, just because it was told by a well respected party. Pop over to comlaw and check the facts, they are all there, gratis.
Some time back, I saw in a LAMEs field note book, CAO 108.6. I had to advise him that his notes were stale, as I knew 108.6 had gone long ago. He did not know this. I sent him all the info, and he was grateful.

To close, I don't make the lemonade, I just sell it.:E

[Dick Smith]

Fascinating. On Monday I will go back to Cameron's and see what they say.

Watch this space!

[Oracle1]

In fact, if it weren't for CASA and these ridiculous expenses, perhaps aircraft owners could afford a new aircraft and their 40 year old c172 could be sent to the scrap heap where it belongs.


My 1961 crap 172 is in better condition than when it left the factory thank you. And it still does the job better and more cost effectively than a lot of the "modern" junk sold as aircraft today. Aerodynamics hasn't changed and materials science has crawled forward somewhat. What has made huge advances is electronics. My ipad combined with two GPS, (Dynon EFIS, not for use just ornamental, the most accurate and reliable instrument in the aircraft) and backed up by an iphone makes my 172 a highly effective tool.


Dick stop whinging about it costing you $1000 to do a compass swing and making out that you care about everyone else getting stung for it. First world problems. Put the chopper on one of those specially constructed trailers that litter airstrips around the country and push it around on that.

As for CAO 100.5 blah blah put in a foxtel screen with new plumbing and tell the designers to make sure it can cross calibrate itself given they just sodomised you for tens of thousands of dollars for a product that dynon can make for one tenth of the price. For most fixed wing owners the compass swing is a small part of of the avionics calibration, which in my opinion is a valid maintenance requirement. If the technology had kept up it would be self calibrating as opposed to having to pay a human to do it.

Aviation is an extortion racket from head to toe and its time to pay the piper.

[Hasherucf]

Thunderbird Five didn't I just say that ??



Arnold E
until proven defective

I mean obvious defects like bubbles , I find they are lucky to last 4 years in a hot environment anyway.

Oracle1
Put the chopper on one of those specially constructed trailers that litter airstrips around the country and push it around on that.

Are you saying do a compass swing on a big lump of metal ??

[noooby]

Or..... Get the rules/AWB's changed so that a GPS system is mandatory. Then you don't need a compass.

Everyone is spouting off about how everyone carries a GPS these days and how they are much more accurate, and they are, but they are not MANDATORY in most circumstances. If you want to ditch the compass forever, get the GPS loaded on to your aircraft as basic equipment in the paperwork and use that as an alternative means of compliance for the compass compensation.

As far as cost for a compass swing, for a wheeled helo, it is only the pilot and mechanics time. As it is a maintenance run, it is not logged on the machine. Not where I come from anyway. Skids are different of course ;)

You can also air swing a compass, flying on the cardinals and working out your errors. That is how a lot of the big aircraft do it. An extended circuit will do it. We used to do it during training with a mech on board to take the readings while the crew flew an extended circuit (long time ago of course!).

[Creampuff]

Arnold

If you planned your flight properly, and navigated properly, you'd know your heading and track, within a couple of degrees, and you'd know your groundspeed within a couple of knots, absent a compass and absent any GPSs.

If you checked the accuracy of your altimeter/s, in accordance with AIP, at the commencement of your flight, you'd have a good idea of the accuracy of the reading/s. If you have a transponder with Mode C, you can confirm the accuracy of the reading/s at altitude.

If you couldn't manage to do a few circuits in your RV7, without an airspeed indicator, you don't know your aircraft well enough.

I'll say it again: 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.

The experiment has been run in the USA and the results are in: The Australian approach is a complete overkill (literally).

[Aussie Bob]

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.

How articulate. Sums up the entire nation, not just aviation.

[Check_Thrust]

noooby:
Everyone is spouting off about how everyone carries a GPS these days and how they are much more accurate, and they are, but they are not MANDATORY in most circumstances.

Unfortunately GNSS units still are subject to RAIM outages so whilst this is the case I do not think that CASA will allow it to replace the magnetic compass no matter how much more accurate GNSS units are.

Creampuff:
If you have a transponder with Mode C, you can confirm the accuracy of the reading/s at altitude.

For this to be the case you would have to be certain that your altitude encoder, which gets its information from the same static source as your altimeter, is reading correctly. If there is an issue with the static pressure system both your altimeter and altitude encoder will be in error and the mode C readout to ATC isn't going tell you that. Whether or not a big enough discrepancy would result from this issue to cause any real dramas is another story if your altimeter was within tolerance prior to departure.

[Creampuff]

So when I report to Departures, "Turning right, climbing to 7,500', passing 3,300'", the dudes in ATC aren't checking the accuracy of the Mode C info?

C'mon. This is like CASA Avmed arguing that CVD creates reals risks.

[Check_Thrust]

They are checking that there is no discrepancy between what your seeing on your altimeter and what they are seeing from your altitude encoder. As I said before, if there is an issue with your static system this will affect both (quite possibly by the same value).

Talking about the static system when the topic is about instrument calibration is a bit of a thread drift and I apologise for that.

[Fred Gassit]

Creampuff is talking a lot of sense on this thread. So long as flying is an outdoors activity these instruments really should just be confirming what you already know. I dont see why (for vfr at least) they cant be on condition items.

If your situational awareness is so suspect that you cant detect gross errors in a mag compass you really need to question your proficiency.

PS. Sorry about the nylocks Hasher, Dynon supplies em as standard!

[Arnold E]

If you have a transponder with Mode C, you can confirm the accuracy of the reading/s at altitude.

As I have posted earlier, the above statement may not necessarily be accurate. Remember I said I found a FACTORY BUILT aircraft with the encoder hooked up to the pitot line. This paticular aircraft had not flown in controlled airspace. In any case I have seen encoders many hundreds of feet out of cal. when tested.

[Arnold E]

If you couldn't manage to do a few circuits in your RV7, without an airspeed indicator, you don't know your aircraft well enough.

Correct, I have not got anywhere near enough hours on it yet to safely do circuits without an asi. (Actually not quite true coz I do have a reserve lift (AOA) indicator).:)

[Creampuff]

I said I found a FACTORY BUILT aircraft with the encoder hooked up to the pitot line. This paticular aircraft had not flown in controlled airspace. In any case I have seen encoders my hundreds of feet out of cal. when tested.Oh the humanity!

Clearly Australia needs more mandatory maintenance. More mandatory maintenance must mean more safety.

[Arnold E]

Clearly Australia needs more mandatory maintenance. More mandatory maintenance must mean more safety.

Yeah, Ok you win.:) Lets not have any mandatory instrument maintenance at all and save ourselves $$$$$.

As I have said, I personally believe that the 100.5 checks which does not include a compass swing to be one of the few sensible checks that CASA has introduced,
especially for aircraft being flown by multiple people who may be unfamiliar with that particular aircraft. I concede that privately owned and flown only
by one pilot, not so much necessarily,......maybe. I have however found some right dogs whilst doing these test on aircraft of the latter category.
However,as I said, you win.

[Oracle1]

Are you saying do a compass swing on a big lump of metal ??


Not that hard to make something non ferrous if you are doing lots of chopper compass swings. My point is the chopper should be able to be manipulated without running the engine.

[Eddie Dean]

AWB 34-008 details the compass calibration requirements of aircraft with a certificate of airworthiness.
I note that it stipulates engine(s) running and all systems operational.

How does that compare with doing it on a non ferrous trolley and engines off?

Of interest to Dick Smith is the paragraph that allows you to have a system of maintenance that stipulates a different elapsed time for compass swing.

I note Arnold E has carried put the "new' 100.5 requirements on light aircraft, the price your compatriots are charging is outrageous, especially out here in the bush. Nearly $6000 all up to get two light helis done, took less than a day.

[Creampuff]

Lets not have any mandatory instrument maintenance at all and save ourselves $$$$$.I didn't say that there shouldn't be any mandatory instrument maintenance. :=

This is why the GA community in Australia is such easy pickings for the regulator. Very few people in it are able to have a rational discussion, based on facts and data.

[Oracle1]

Read my original post and put it context. I don't care about how you arrive at a compass swing the instrument is an inaccurate relic. Do we need to alter engine RPM and allow for changing alternator fields? Do you want to take it to that level? The fact that all these factors need to be considered confirm its unsuitability compared to modern electronics. Modern electronics cross calibrate, expending any energy on compasses is just pissing money against the wall.

Ask yourself honestly, when was the last time you actually used the compass as a primary means of navigation?

Given today's technology the avionics should self calibrate.

[Progressive]

Dick,

By less prescriptive I guess you are referring to the NZ allowance for acceptable means of compliance and the following exemption from Canada:

"(b) The annual calibration requirement of (a) does not apply to an aircraft operating under an air operator certificate, or to any large or turbine-powered pressurized aircraft, where:

(i) the aircraft is equipped with two independent stabilized magnetic direction indicators in addition to the non-stabilized direct reading magnetic direction indicator; and"

(ii) a procedure for monitoring and recording the performance of the magnetic direction-indicators is detailed in the flight training unit's, or in the air operator's approved maintenance control manual approved pursuant to CAR 406 and CAR 706 respectively."


I fail to see how this is less prescriptive than the exemption requirements of CAO100.5:

"exempted aircraft:
means an aircraft with an approved system of maintenance
(SOM) under regulation 42M of CAR 1988, or with a maintenance schedule under regulation 41 of CAR 1988, but only if the SOM or the schedule incorporates instructions for the continuing airworthiness of instruments and instrument systems fitted to the aircraft that would otherwise be subject to the additional maintenance requirements set out in clauses 2 to 6 of this Appendix."


Do I work for CASA? NO.
Have I ever worked for CASA? NO.
Can you say the same?


Surely a well supported industry petition (there are plenty of people here who would submit) with evidence (costs you are claiming) to have the wording a CAO100.5 amended to require the checks at the first Maintenance Release issue after the date of expiry (much like weight and balance checks) would be a more valuable use of your considerable financial and political clout than complaining on a public forum.

This would ensure the checks were only done during times when a LAME(and in the case of helicopters a pilot) was required anyway and a safety case should not be too hard to build for this.

[Eddie Dean]

Yes indeed Oracle, you can certify for the compass swing no matter how it is done, or whether it is correct or not, or conforms to the AWB or not. It's your licence.

[Arnold E]

Very few people in it are able to have a rational discussion, based on facts and data.

I don't believe that I have been irrational. I agreed with you that I could not fly my RV7 in circuits without an asi and gave the reason, ie not enough hours on the aircraft to be confident without an asi. My old Cessna, however is a different story, I had heaps of hours in that and rarely had to refer to the asi on final. Take the case of a recently tested aircraft, again factory produced that was used for training and had an asi that read 7 knots FAST at 70 knots.....7 knots. Now clearly this was not a problem for the owner who was very familiar with the aircraft, but he was using it for training new guys/gals. now the trainee is inexperienced and gets his licence and at about, say 30-40 hrs goes and flys his mates plane of the same type. He does as he is told and flys by the numbers. do you not see, at least, a potential problem here. If you dont then I give up, its become clear to me that at 30-40 hrs total time you were capable of flying the Space Shuttle by feel alone, but let me tell you, the skys are filled with people not as skilled as you.

[Hasherucf]

Eddie Dean
Nearly $6000 all up to get two light helis done, took less than a day.

God Damn. I will do it for 5K :}

[thorn bird]

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]

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]

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]

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]

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]

These people are very very clever, unfortunately much cleverer than usNot 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]

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]

"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]

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]

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]

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]

altimeters are calibrated to within 100ft of actual.

WRONG.....read 100.5 and tell me what it says.:ugh:

[Hasherucf]

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]

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]

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]

Jeez creamie!!
Bite your tongue!!

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

[Dexta]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Google "Waddington Effect".

[Oracle1]

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]

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 (http://www.sportaviationonline.org/sportaviation/201103?pg=103#pg103)
EAA Sport Aviation - March 2011 (http://www.sportaviationonline.org/sportaviation/201103?pg=104#pg104)

and this article which is half plagiarised from wikipedia

The Waddington Effect « Opinion Leaders (http://blog.aopa.org/opinionleaders/2014/01/14/the-waddington-effect/)

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/engineering-systems-division/esd-60-lean-six-sigma-processes-summer-2004/lecture-notes/7_2prevent_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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

for a vfr altimeter.

VFR / IFR same requirements.

it is a calibrated instrument

When was thee last time ?

[Hasherucf]

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

[Arnold E]

Huh? 100.5 details the checks required?

[Hasherucf]

I'm implying its not that simple! Plenty more to check

[Arnold E]

Yeah, the checks are datailed in 100.5 attachment 1 appendix 1 c2, and yes it more that just saying 100ft is close enough. In any case at SL its 20 ft.

[LeadSled]

You quoted much of what AOPA had to say. Please send me a link to the original "Waddington Effect" paper

hasherucf,

I have absolutely no idea what AOPA ( I presume you mean AOPA/USA) has said on the subject.

My knowledge of the subject is only a little bit second hand, as it comes from an RAF maintenance officer who was a distant but fascinating relation.

As for your demands for a (academic) paper, I dare say that, at the time, the chaps were a little busy fighting Hitler, and formal studies, collection of statistics etc was not front of mind.

Indeed, I have only heard it called the "Waddington Effect" in recent years, but civily the general principles were well understood by the 1950s, it was covered in Eng1 at Sydney Uni., and undoubtedly in Engineering courses at other universities. The WWII RAF experiences were quoted.

In the RAF setup, Squadron/Wing COs had wide ranging authority, their Engineering Officers --- just from day to day experience saw the serviceability of otherwise of aircraft, particularly larger aircraft, and convinced their COs of the "if it ain't broke, don't fix it" approach.

Quite simple, it worked.

The first "studies", of which I am aware, which might satisfy your demand for a "paper", was work by United Airlines in the late '40s or early 1950's, and as developed over the years, has become the basis of much civil and military maintenance control processes. --- on condition maintenance.

Re.maintenance error, in the modern airline sphere, it accounts for the "most probable cause" or "root cause" in about 35% of accidents, not a trivial percentage.

Tootle pip!!

[Hasherucf]

Sure Leadsled

I just wanted to read the original paper. The only thing I could find was a link to a book about submarine operations.

Seems its written in "C. H. Waddington, OR in World War 2: Operational Research against the U-Boat"

So I am trying to get a copy !

[LeadSled]

Hasher,
Try and get your mind around the idea that it didn't start with a "paper", although there may well have SUBSEQUENTLY been something written that gave rise to the name "Waddington" effect, but it was certainly NOT invented at or confined to Waddington.

Indeed, one of the interesting stories of the day was the introduction of Catalinas with PW1830 engines, at the other end of the country, one of the first experiences of US aircraft and engines in the RAF.

The reliability of the engines came as somewhat of a surprise to those only familiar with English engines. A engine that could run for twelve hours plus, and only needed the oil topping off to do another twelve hours, without having to replace a single cylinder, came as a bit of a revelation.

Engines with overhaul lives measure in 1000s of hours, not 100s (if you were lucky) were just not believed, at first.

To not have to tighten nuts using a micrometer to measure stud extension, alone, saved hours. The use of gas pressurised compression rings on pistons, as opposed to spring steel or other solid and inflexible rings were another revelation.

I think "necessity is the mother of invention" just about covers it.

Tootle pip!!

[Old Akro]

My understanding is that when the new 100.5 regs were introduced, it actually omitted compass swings. At the time of our last 100 hourly ours was done expecting that CASA would soon correct that.

100.5 re-introduces a range of periodic checks that were previously dropped as being not warranted. eg, fuel gauge calibration.

I did the exercise a while back of going through our log books and putting in a table all the calibration results for the key instruments over the aircraft's 30-odd year life. The main thing I leaned is that many LAME's can't calibrate for sh*t. With full trend data, some calibrations have clearly been just plain wrong. Watching our last fuel tank calibration, it was clear that the guys doing it didn't understand what they were doing . But to challenge it means another fuel drain and repeating the exercise which would blow another $1500. And our electronic fuel totaliser is more accurate anyway.


The other thing I learned is that most instrument don't change in calibration significantly. I challenge those supporting regular calibration to do the exercise.

[Jabawocky]

Akro :D

Nail on head.

Last 1000hrs 5 years, no notable changes at all. And fuel accuracy within a litre over 250. In fact most error comes from venting of fuel on hot days out the breather.

[Creampuff]

Hear! Hear! OA.

It is obvious to me that the people who make these rules are ignorant of and uninterested in objective facts and data.

"No amount of science or hard data can over-come the comforts offered by a closely held superstition or belief."

[Hasherucf]

"No amount of science or hard data can over-come the comforts offered by a closely held superstition or belief."


:ugh: This is why we have religious wars. It's 2015 people :ugh: :ugh: :ugh:

[Creampuff]

It’s also why there are still mandatory compass and fuel gauge calibrations for private aircraft in Australia, and why you refuse to accept the reality of the Waddington Effect.

[Hasherucf]

No I refuse to accept The Waddington effect in your terms.It's a bastardisation of terms used in political motive to push a point (Probably by AOPA). Maybe even to sell a book. I believe it exists but not in the extent purported in this thread. Only modern evidence was in a MIT study and that was 1.4% of aircraft availability.

Waddington Effect is borrowing the term used from CH Waddingtons biological studies . I listed all of this in a post previously.

[Creampuff]

QED. :ok:

[Creampuff]

I must say, Hasherucf, your googling skills seem a little poor, despite Leaddie urging you to 'try harder'.

3 minutes of googling led me to, for example, an archived post on the US Defense Acquisition Portal by the Director of Logistics and Sustainment Centre, in which he commends for reading an article in Sport Aviation Magazine entitled “The Waddington Effect: More Maintenance Isn’t Necessarily Better”. The Director comments: The author offers interesting perspectives on the history of Reliability Centered Maintenance (RCM), including the once-classified work by H.C Waddington and his British Coastal Command Operational Research Section colleagues during World War II. In it, he also cites a separate, yet equally compelling article in the September 2010 Bulletin of Military Operational Research Phalanx Magazine entitled “ The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness”, as well as a pioneering 1978 RCM report written for the Department of Defense entitled ”Reliability Centered Maintenance”, by F. Stanley Nowlan and Howard F. Heap.
The “The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness” article is available here: http://cmapspublic.ihmc.us/rid=1HTKPYHY3-10D9MZ0-11ML/ I quote but a few paras: … Conventional wisdom held that, if more preventive maintenance events were performed on each aircraft, fewer problems would exist – and potential problems could be caught and fixed – and thus the effectiveness of the fleet would surely improve. Conventional wisdom was, as is so often the case, wrong. It would take Conrad Hal (C.H.) Waddington and his Operational Research team to prove just how wrong.

C. H. Waddington (1905-1975) is best known, today, as one of the first developmental geneticists – and as a person who did not believe that genetics, embryology, and evolution were separate sciences. But his interests and contributions covered a much broader spectrum. Those individuals involved in the field of Artificial Intelligence recognize him, or should, as one of the pioneers of the optimization technique designated as Genetic Algorithms. Those in the military recognize him, or should, as one of the leaders in the development of a new, unorthodox, and – at one time – highly suspect (i.e., by the military) approach to military planning, both strategic and tactical.
…
..efore scurrying about to provide a slick briefing on a scheme that might or might not work, [b]Waddington and his team had the audacity to stop and think. They requested and analysed the supporting data, talked with maintenance crews, and took time to carefully and personally observe actual maintenance events (a decision quite unlike that of too many “analysts” who prefer to remain in their warm and comfortable offices, poring over and processing data provided from “the outside”). Furthermore, rather than getting the wrong answer, or the politically correct answer, fast, these Operational Researchers trod the lonely path of seeking a proper, effective, and practical answer.
…
The conclusion Waddington and his group reached … was, in Waddington’s own words, that “inspection tends to increase breakdowns, and this can only be because it is doing positive harm by disturbing a relatively satisfactory state of affairs. Secondly, there is no sign that the rate of breakdown is beginning to increase again after the 40-50 flying hours, when the aircraft is coming due for its next [preventive maintenance event].”
…
In other words the Waddington Effect is defined as a “spike” in the number and frequency of unscheduled events “closely” following a scheduled event – followed in turn by a gradual decline in the a rate of occurrence of unscheduled events to a “more normal level,” until a repeat of this same, troublesome effect following the next scheduled maintenance event.
…
[And just to support Leaddie’s earlier post: Once these recommendations were implemented the effective size of the British Coastal Command air fleet was increased by more than 60 percent! In other words, a change in maintenance protocols and their documentation (as motivated by the identification of the Waddington Effect) was as effective (and far less costly or time consuming) as the allocation of an additional 60 percent more aircraft….[My bolding]

I also note but a few paragraphs from the latter report (available here (WARNING: IT IS A BIG FILE): http://reliabilityweb.com/ee-assets/my-uploads/docs/2010/Reliability_Centered_Maintenance_by_Nowlan_and_Heap.pdf
One of the underlying assumptions of maintenance theory has always been that there is a fundamental cause-and-effect relationship between scheduled maintenance and operating reliability. This assumption was based on the intuitive belief that because mechanical parts wear out, the reliability of any equipment is directly related to operating age. It therefore followed that the more frequently equipment was overhauled, the better protected it was against the likelihood of failure. The only problem was in determining what age limit was necessary to assure reliable operation.

In the case of aircraft it was commonly assumed that all reliability problems were directly related to operational safety. Over the years, however, it was found that many types of failures could not be prevented not matter how intensive the maintenance activities. …

A major question still remained, however, concerning the relationship between scheduled maintenance and reliability. Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. This was not because the intervals were not short enough, and surely not because the teardown inspections were not sufficiently thorough. Rather, it was because, contrary to expectations, for many items the likelihood of failure did not in fact increase with increasing operating age. Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …[My bolding]

In short: Belief versus science and hard data.

Upon which do you reckon periodic calibrations of e.g. compasses and fuel gauges on private aircraft in Australia have been mandated?

[thorn bird]

Awww, come on you guys, give them a break, there are limits to the number of ways they can waste our money, they must be running out of ideas by now.

[Sunfish]

Hash, I can assure you that the Waddington effect is real.

In relation to maintenance the probability of stuffing something up when you reassemble and install it is not zero and the defect may not be discovered in initial testing. This effect gives rise to what is termed "infant mortality" - failure shorty after installation in components.

I independently proved the existence of this effect by studying and analysing failures of autopilot gyros in the Ansett aircraft fleet in the late 1970's. Almost all of them occurred shortly after overhaul and reinstalllation. They had very delicate bearings which were easily damaged. We increased their reliability by doubling their life limits.

[Creampuff]

We increased their reliability by doubling their life limits.If only Ansett had cast off, entirely, the closely held superstitions and beliefs, and put the autopilot gyros on condition instead. Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. … Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …

[Sunfish]

"On condition" was a bridge too far for the CAA in 1978;)