Strikemaster re-winging

[compasscall]

I seem to recall that the JP5 wing and the BAC167 wing were one and the same. This was done to save money by not having to design a wing for the JP5. Some of the RAF JP5s had tip tanks fitted permanently for nav-ex training.


CC

[compasscall]

Just found the reference about the JP5/BAC167 wings.




Hope this works!

CC

[corsair67]

Just been reading the latest edition of Aero magazine, and in it there is a very interesting article about the Macchi MB326H in RAAF service, and some of the serious wing fatigue problems that those aircraft suffered.

Apparently some of the aircraft were suffering wing surface cracks by the time they'd reached 2000 hours. The problem really came to a head in 1990 when A7-076 crashed off the coast of NSW after suffering an in-flight wing failure. New sets of wings were ordered from Aermacchi to keep 30 of the Macchis flying until the Hawk was in service with 76 and 79SQNS.

I wonder if this is one of the reasons that there are no ex-RAAF Macchis flying in Australia?

[Calum]

corsair67 said:

Calum, why was wing cracking such an issue with the Strikemasters in RNZAF service?

Some of those airframes (NZ6371-NZ6376) would have been less than 10 years old when the cracking first became an issue.

From memory it ws due to lots of low level operations in NZ's Dense air.

[kevin]

The preliminary report on the breakup is here:

www.atsb.gov.au/publications/investigation_reports/2006/AAIR/pdf/aair200605843_prelim.pdf

[corsair67]

Cheers for posting that link, Kevin.

Geez, there wasn't much left of the fuselage wreckage after the fire.

[scurvy]

Re- RSAF 315 Crash in Bathurst 2006.

I know its old news but the reports take some time to come out.

www.atsb.gov.au/publications/investigation_reports/2006/AAIR/pdf/aair200605843_IFR.pdf


Turns out it may not have been the wing that failed first but the tail?
I'm not a pilot, any of you pilots care to guess how a strikemaster would peform without a rudder and\or elevons?


The Singaporean strikemaster had a very dubious history.
But the deceased owner certainly knew what the deal was.
Just cant imagine why he would do that to the wing lug\s.

I knew all about the ex NZAF wing issues, it seemed to be a well understood engineering issue and provided the aircraft was operated within its limitations and inspected it shouldnt have been an issue. I didnt think for a moment someone who would basically polish out cracks in such a critical structural component would be allowed aywhere near an aircraft, let alone fly it and take paying passengers. I have to presume he was just incredibly stupid because if I presumed he had no conscience then he wouldnt have flown the aircraft himself.

I would do the joyflight again, but only in an ex NZAF example or a JP, and like I said in another post, what are the odds of me coming across this sort of stupidity again.

[FlyNavy]

Scurvy,
I have this and your other post (http://rnzaf.proboards43.com/index.cgi?board=Aussie&action=display&thread=1194403418&page=1) and the PDF link (http://www.atsb.gov.au/publications/investigation_reports/2006/AAIR/pdf/aair200605843_IFR.pdf). Not sure why you know/assume that the owner knew about the wing crack defect? Flying a jet warbird without functioning ejection seats to me does not sound ideal - perhaps that is another matter altogether.

You have asked how an aircraft (Strikemaster) would fly without tail/elevator components. 'Not (well) at all' would be my answer. If we can assume that in different circumstances flying straight and level at high altitude IF the tail & elevators separated for whatever reason then the aircraft would be uncontrollable with ejection/egress being the only course of action. Perhaps under these above circumstances the aircraft would be breaking up anyway and doing so in such a manner that any egress would be impossible without aid of an ejection seat.

IF the rudder fell off then as indicated elsewhere recently (http://rnzaf.proboards43.com/index.cgi?board=Postwar&action=display&thread=1199693596) the rudder is not essential in a jet but I'm assuming that if a rudder fell off that otherwise it would not damage the aircraft (BIG IF).

As to the question what failed first I don't know. Possibly the counterweight that fell off, having no aerodynamic qualities, just fell to the ground vertically (more or less) while the other bits had a tendency to flutter down differently. Only my guess and I don't claim to know otherwise.

I would be interested to know who 'polished out' the cracks.
Phil.

[scurvy]

Yes, it is an assumption that the owner\pilot knew about the existing "blended out" wing lug defects. Whether he himself thought it was appropriate or whether he had bad advice is not known and may never be.

I make the assumption that owner\operator knew based on information from 2 independant sources that the owner\operator had previously advocated the blending out of these specific defects, once to a prospective buyer of one of his strikemasters and on another occasion to another operator of the type.

Whether there were new defects or defects that had propagated from the previously blended out defect\s is not made clear in the report. What is clear in the photo in the report is that a considerable amount of material had been removed from the lug previously to remove cracks.

I dont know if there are situations where blending is acceptable in an airframe to stop the propagation of fatigue cracks, its a similar principle to putting sticky tape on your windscreen to stop a crack from progressing.

I was a fitter and turner by trade. Blending out defects like that would be done to temporarily extend the life of a part until a replacement could be found. That would never be done in a situation where there was a risk of injury or loss of life however. Doing this certainly doesnt solve any problem, it merely delays the inevitable failure of a fatigued part. New defects will almost certainly appear.

While it may not have been a wing failure that caused this crash, the revelation of the blended defects in such a critical area does tend the characterize the sort of maintenance that may have been performed (or not performed) on the rest of the aircraft.

Its just the sort of thing the recreational warbird industry didnt need.

The question of "bang seats" in this type of operation has been discussed for and against in other forums with no clearly compelling argument from either side of the argument.

Its not simply a cost & maintenance issue. There is the question of having untrained paying passengers being in control of an armed seat. There is the problem of having active ordinance in a civil aircraft. Many would argue that as the majority of prop "joyflight" operations have no emergency egress method at all why should these aircraft maintain active seats. Then in the particular profile this aircraft was flying there is an argument that there would be no time to eject and\or the egress would be fatal anyway. At the end of the day its up to the paying passenger to make the choice. The only "joyflight" Ive had a parachute on for was in a strikemaster. Any other of the flights I have taken offered absolutely no emergency egress method.



I think exactly who blended out the defects will become known in the final ATSB report. Whether that is found to be negligent and\or against some rule or just a stupid thing to do is another story I suppose.

I'm an enthusiast, I love the fact that these birds are still able to be flown and that a punter like me can enjoy a flight in them. But if the cost of keeping them in good flying condition outweighs the commercial reality of a business then as sad as it is they will have to stay on the ground.

Of course there are risks with this type of operation but I am stunned to find that an operator could knowingly, significantly, increase that risk, not only to himself but to paying passengers.

[FlyNavy]

Scurvy, (Drink more "Limers" the best drink - non-alcoholic - that the Navy ever invented)
Thanks. I find it difficult to believe that the owner/operator 'pilot who died?' would have made such a decision about the fatigue cracks knowing the implications. As you say perhaps we will know the full story one day. As to the question of taking passengers on these 'risky' jet warbird flights, that is another question which is similar to the unqualified owner/operator/pilot making a maintenance decision - if you follow me. If the pilot made the decision I would suggest he was not qualified to have a say in how his aircraft was maintained. Someone qualified needed to make appropriate decisions.

Similarly passengers are not qualified really to make decisions (in my estimation) about whether it is safe to fly in a jet warbird without an ejection seat. They don't have enough information to make an informed decision, and this perhaps is where the pilot/owner/operator has the qualification for the decision.

I don't buy the argument that 'civilian' (jet warbird) aircraft should not have ejection seats. If the civilian passenger is put through appropriate education and drills they will gain the qualification to fly as a passenger. Similarly Navy maintainers gained that temporary qual. by some means including a thorough briefing before flight by the pilot. If these precautions (including the ejection seats) adds cost with extra safety to the warbird jet then so be it. IMHO the pilot should be able to fly without a seat but NOT with passengers. This is not justifiable for whatever reason. I don't buy the 'parachute strapped to the back' compromise either. Ejection seats were made for jets and are needed to ensure aircrew are able to escape in flight. Nothing else will do.

Prop aircraft are a different argument and I'm not talking about them. The warbird jets need to be better regulated in this regard. If this means that some don't fly then at the potential cost of lives saved this is a good thing. No? If you are an enthusiast then getting the necessary training to use an ejection seat will be a breeze.

Let us get to your last paragraph above. You are stunned. Yes I am stunned if what you say is true but I'm stunned for also different and the same reasons. Include in your stunned paragraph that I am stunned that a trained military jet pilot wants to fly a military jet without an ejection seat as well as all of the above about increasing the risk to paying passengers. [One question: Do paying passengers have different rights as opposed to non-paying passengers?]
Phil.

[phil]

Then in the particular profile this aircraft was flying there is an argument that there would be no time to eject and\or the egress would be fatal anyway.

Why, was he inverted and under 300 feet or something? The Blunty uses MB PB4 seats that are very capable. They are 0-90 seats, so would have worked even at very low levels.

[corsair67]

Yes, P.O. Lindsay found out how good the seats (and MDC) were in NZ6367 back in 1985!

[trimotor]

NIL