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View Full Version : Pax flat tyre thread continued briefly


megle2
5th Sep 2011, 08:48
flat tyre thread locked prematurely

If we encourage pax to report observations which they think maybe important
we should treat their comments with a little more respect rather than rant on as per the locked thread

Mods, you can close it off now

ampclamp
5th Sep 2011, 11:01
Agreed, sometimes they may just see something important. The more eyes the better. Aloha springs to mind. Tragic the pax did not say something. Better a thousand false alarms than one avoidable prang. That is why we want to keep preflts.

Wunwing
5th Sep 2011, 21:54
I paxed on a B737 weeks before a major structual incident with the same Pacific island carrier. I noticed a large number of screws missing overwing and reported it, with no apparent interest from the pilots.

I also operated a B747 ex BNE when the twr reported "something big just fell off your aircraft just after rotate". The something big turned out to be a whole tread which caused damage to the emergency brake plumbing, gear door and fuselage. It later transpired that a tyre had failed long before we had reached the rwy and it was heard by pax and cabin crew, but no-one told us.

And the accident in Canada where pax noticed the ice and snow build up on the wings of an F28 but the message didn't reach the pilots.They all died in that one.

Not all pax are idiots and disregarding their observations can be expensive or even fatal.

Wunwing

glekichi
6th Sep 2011, 00:40
Notified a hostie on a 737 flight recently about a seat that was not bolted down correctly and was rocking about. No idea if she actually told anyone but she didn't seem interested whatsoever.

Mad (Flt) Scientist
6th Sep 2011, 00:49
If I'd seen something like that on a flight and the crew member I told seemed disinterested, I'd have no qualms about saying more than just "thanks for the flight" when disembarking and the captain or F/O is stood by the exit. If you do believe something is wrong, especially if you have any technical basis for that belief, you have a moral (and in some jurisdictions probably also a legal) duty to make it known to the right person.

I certainly wouldn't want to be in the position of telling NTSB etc. that I'd seen something and decided not to bother anyone ... personally I've never seen anything that was worthy of that action, but at least one colleague has, and did the right thing.

Wunwing
6th Sep 2011, 09:03
Taking things further depends on how bad it is and where you are. In some jurisdictions a further report means that you have to stay there at your own expense while things are sorted. And then find your own way with new tickets at your expense.

So not an easy decision if not obviously life threatening.

Wunwing

teresa green
6th Sep 2011, 11:10
Interesting. Pax noticed peeling on the skin of the Hawaiian Airline 737 that had a flight emergency some time ago and told nobody, the skin certainly peeled and they were lucky to survive,so speak up folks.

ampclamp
6th Sep 2011, 21:11
TG I think you are referring to the Aloha 737 incident I raised a few posts back.Not Hawaiian

Brian Abraham
7th Sep 2011, 07:05
And the accident in Canada where pax noticed the ice and snow build up on the wings of an F28 but the message didn't reach the pilots.They all died in that one.Not all died, 21 of the 65 passengers and 3 of the 4 crew died. Bad enough.

Interestingly only one passenger made comment to a FA asking what the crew intended to do about the snow/ice build up. The FAs were concerned but hindered by the feelings that pilots did not accept them as an operational part of the crew.

Also, among the passengers were two captains, one a Dash 8 the other a DC-9. Both believed the crew were aware of the contamination and they would be deiced. The -8 captain said he believed professional courtesy precluded an off duty pilot from drawing the attention of the flight crew to safety concerns.

Milt
7th Sep 2011, 07:52
Serious Defect Report by Pax.

Following is my Defect Report only advised so far to the operating airline through its "Guest Relations" access on its website on 2 Sep. I am left wondering how "Guest Relations" would handle such a report. My consternation at no response is mounting and my deadline to declare the type unairworthy has almost been reached.

xyz Aircraft - Serious Defect
There appeared to be a serious defect with a flap track/extension mechanism of the xyz aircraft operated by the Airline as flight No X out of A to B on Tuesday 16 August 2011.
The particular item is the outboard track for the inboard flap segment on the right wing.
Soon after engine start the flaps were extended to the take off setting. During the extension the underwing fairing around the flap track began a horizontal convergent flutter which continued until about V1 during take off. The flutter began again after landing and during taxi.
The flutter had a varying amplitude up to an estimated 2 cm at the fairing's trailing end with a frequency of about 10 Hz.
My perception was that the fairing was loose because of either an inadequate or broken attachment or a design defect.
If the assembly fails and there is no protection against asymmetric flap extension/retraction then the consequences could be expected to be catastrophic.
If the problem is a design defect then a simple change in mass balance at the fairing's trailing end may correct the flutter.
I did write a note addressed to the Captain advising him during deplaning at B that he should have some concern about the above problem explained in simplistic terms.
My observation were made from a window seat close to the wing trailing edge. I am a widely experienced retired experimental test pilot and expect to be reassured that the problem will be corrected.
I did not have the opportunity to observe whether the fairing on the left side had a similar problem nor did I determine the registration number of the aircraft.
With concern
Milt etc.

rutan around
7th Sep 2011, 21:10
Milt
I also have a bit of experience with experimental aircraft and tend to take notice of abnormal flutter.As a PX flying into Sydney I saw flutter where and in the mode you describe. I reported it to the pilots and they said they said they would report it to their engineers. This occurred about Dec last year.Seems like nothing much has been done about the problem. I certainly wouldn't keep flying that aircraft until the problem was sorted.
Cheers RA

Milt
8th Sep 2011, 04:13
Surprise surprise - now there are at least two of us concerned over the same problem. Thanks for your post RA.
A response has just been received from the airline as follows with a couple of changes to not yet reveal the identity of the airline and aircraft type.
_____________________
"Senior Fleet Engineer

At that time VH - XXX was inspected multiple times, and nil faults found, to indicate there was not an immediate airworthiness issue.
In this case Mr Cottee has reported what appears to be normal conditions of horizontal vibration at the upper end of the Flap moveable Fairing.

Aircraft Type Fleet Manager

When informed of this concern we initiated a detailed inspection of the inboard flap area L/H & R/H. No defects were found. This inspection was carried out by a highly experienced Licensed Aircraft Engineer cerified on type. The movement that Mr Cottee was concerned with is considered normal and comes from the armlink assembly moving on the bushing clamp. This is considered a normal movement, designed to do so. The Airline operates a rigid system of maintenance and on-goings to ensure the safety of our aircraft which involves inspections of the flight control system at scheduled intervals."
________________________
My concerns over airworthiness remain. Had I been involved with the certification of the type I would not have accepted the fluttering for two reasons. Firstly anything fluttering the way this component does will inevitably lead to something failing. Secondly the effects on passengers is hardly conducive to them wanting to stay on board.
The flap fairings are immeditely behind the engines and my conclusion is that eddies from an engine's efflux set up the flutter conditions.
I guess it is now up to the manufacturer to address the problem. I do commend the airline for its reaction to yet another passenger suggestion even if it did come from a TP.

What would you experts do next?

VBA Engineer
8th Sep 2011, 05:09
Nothing.

It has been inspected and cleared by a type rated LAME.

Splitpin44
8th Sep 2011, 06:50
Yep VBA Engineer said it all.

Its awesome that passengers report defects as long as they don't get the sads when an engineer has a look and tells then they are dreaming.

I think some people may watch too many episodes of "aircrash investigations".

But never the less its good that people speak up, even if you end up being wrong you might at least learn something.

Long Bay Mauler
8th Sep 2011, 06:52
Contact ether Boeing or Embraer, as I guess the airline you are talking about, operates both of these types.

See if the manufacturer respond to your concerns, and if that fails, contact the regulartory authority that gave the type certification.

As a widely experienced retired experimental test pilot I am confident that you would be the best placed person to follow this up.

Good luck.

YPJT
9th Sep 2011, 10:23
I once pointed out to a cabin crew member on a SAA B744 that the one of the inboard spoilers was flapping up and down in the airflow. Her response "It's probably ok, it won't fall off":ugh::ugh::ugh:

I thought, why the fcuk did I bother and just went back to drinking heavily.

Old Fella
9th Sep 2011, 11:28
Splitpin44. Mr Milton Cottee is, as he said, a highly experienced test pilot. I am sure what he observed was, in his opinion, an abnormal condition. I am equally certain that his report was not influenced by watching Aircrash Investigations on TV, but rather by his vast practical experience as a test pilot where he would have often had to evaluate inflight performance of aircraft.

RATpin
9th Sep 2011, 12:25
For what it's worth,the fairing is non-structural and can be mel'd.
In the case of the 73 700/800 you may dispatch without it and by observation,particularly with t'off thrust,they do tend to move around a degree that maybe unsettling for some observers.

rutan around
9th Sep 2011, 22:05
Milt
(.......ANYTHING FLUTTERING THE WAY THIS COMPONENT DOES WILL EVENTUALLY LEAD TO SOMETHING FAILING.)
I totally agree.The component I saw fluttering didn't appear critical to control but.........
A few comments. The component's life would be much longer if it didn't flutter so why not address the problem? I'm sure the engineers checked the component and ensured it complied with design specification. But did anyone ride in the aircraft to see what PXs were on about?
Sometimes there's only a bee's dick between the amount of play that allows a component to flutter or not flutter. Sometimes even slight variations in wear position can effect outcomes. A good example is Cessna 210 nose wheel shimmy. They seem to go forever with no shimmy(flutter) then one day some slight change and away they go. It's not a good answer to say "Well all the play is within specs so it shouldn't shimmy." If the bloody thing does then fix it.
Cheers RA

Splitpin44
9th Sep 2011, 23:13
Old Fella, I've had a look and struggled to find where I said he wasn't an experienced test pilot.

Like everyone eles who reports a defect only to have an engineer tell them they are dreaming, lets hope the has enough experience not to get sad if hes wrong.

Like I said report the defects and even if your wrong you may learn something. Like just know we have learnt that you can MEL said piece or even fly without it fitted.

Gargleblaster
9th Sep 2011, 23:46
Have tried to inform cabin crew on KLM flight AMS - CPH that one of the MLG tires was pre-flintstone standard (square), yep we were jumping in our seats during both TO and landing. Nada, ach, øv.

rutan around
9th Sep 2011, 23:47
To adapt a well worn joke -
Report: Fluttering part nearly needs redesign.
Action: Fluttering part nearly redesigned.

Old Fella
11th Sep 2011, 07:28
Splitpin, I was just emphasising that Milt Cottee would not have made a report had he not felt that what he saw was abnormal. As for an Engineer telling someone they were "dreaming", not the word I would use.

Milt
12th Sep 2011, 05:10
Fairing Flutter Summary

Thanks to all for your posts. I did deliberately seek your posts by asking that question - What would you experts do next?

The answers and the airlines reponse clearly indicate a likely entrenched problem within the general engineering side of airline fleet maintenance, ie a belief that any aircraft type formally certified as airworthy can only reluctantly be seen to have any residual problems. I had hoped that the airline would have advised me that it was seeking confirmation of its preliminary determinations from the manufacturer in case the problem is one that has fallen through the cracks. Now it is my duty of care to take it out of the airline's hands seeking reassurances from both the local regulatory airworthiness authorities and the type manufacturer. I do accept that the problem may well have been previously determined by the certification authorities as satisfactory by means of a specific concession.
I contend that most Aeronautical Engineers will have some knowledge of the all too often diabolical effects of flutter (particularly of the divergent variety) on aircraft or their appendages. Nearly all will not have had practical experience. I further contend that there is little reason for a LAME to know much more than what the word means. Flutter prevention/analysis is a specialty within the Aerospace Engineering domain. Not so with the Experimental Test Pilot. We are all very apprehensive of flutter and any experimental TP will go to great lengths to ensure that the appropriate corners and margins of aircrafts' flight envelopes are approached with much care. We determine the safety margins of flight envelopes as a buffer against unintentional overshoots. Things, often called bonkers, are sometimes used to provide an impulse to excite those areas where flutter is presumed to lurk. I recently saw a high speed movie of an F-18 Hornet's wing approaching self destruct in one of those corners and the designs likely to enable the extension of the margin.

My own experience has been mostly involved with supervision of other TPs endangering themselves, the safety aspects involved and the review of flight tests. Many preliminary test results can be determined in a wind tunnel but there does not seem to be a substitute for flight testing. Most divergent flutters rapidly run away to failure/destruction.

I once flew in an RAF Hunter Mk7 two seater which suffered from what TP Bill Bedford conned me into thinking was rudder buzz when pulling about 3g at supersonic speeds. Its fluttering rudder resisted all our foot forces trying to stop the violence. After delivering 3 sonic bangs to a poor unsuspecting ship I called quits as I had some concern about the continuing integrity of the rear fuselage. The fix was a simple trim tab trailing edge strip rather than a change to rudder mass balance. Other approaches to the edges were no less fraught. Hence my sensitivity in this area.

As for general flap design problems. Flap design seems to be an aircraft designer's nightmare - a compromise between weight and stiffness and the penalties of having to use protrubing tracks/guides. When I was responsible for the RAAF's F-111s being delivered out of their Texas factory way back in the 70s I had to contend with the loss of several flap segments from two aircraft as they prepared to land at Sacramento in CA. A specialist team from the factory had to fit replacements and rerig the whole fleet to revised or correct specifications. Now one of you has told me of his experience with the flaps of another type where by out of adjustment or wear would sometimes allow the guide rollers travelling in the outboard auxiliary flap tracks to come out of the tracks resulting in excessive looseness and the odd loss of a flap segment. Ground inspections did not detect a fault as the rollers usually went back into the tracks during flap retraction.

Current knowledge, experience and wind tunnelling enables reasonably reliable predictions as to the liklihood of flutter anywhere close to an aircraft's flight envelopes.

Milt
22nd Sep 2011, 07:54
More on Probable Flutter
Reno P-51

If ever there was an almost perfect case of Divergent Flutter then the loss of control of the P-51 Mustang at Reno Nevada has almost certainly to be it.

That aircraft was extensively modified for high speed racing and was being operated way outside of its original manoeuvre envelope. The failure of the elevator trim tab is very evident in some very clear photos as is the resultant high g which must have come close to taking a wing off. Having flown the Mustang in combat and training with about 450 sorties I found it was generally nice to fly with good longitudinal stability except with an aft cg which occurred when the fuselage fuel tank behind the cockpit was more than about half full. With a full uselage tank it was a wrestle with it wanting to continuously pitch up or down.

The rudder has an anti trim tab to correct for low or negative horizontal stability.

Never did have any feel for the start of an elevator trim tab flutter but rarely did I fly it beyond its flight envelope.

It came as a surprise to me that the tail wheel extends to the down position under very high g. My last flight in a Mustang ended with - oops - no tail wheel.

It is my bet that Reno crash was a result of divergent flutter or overload of the elevator trim tab whilst the aircraft was being operated well outside of its manoeuvre boundaries.