FireFly Spin

[ABOOD13]

Hello Everybody
Any body have an Idea why the British FireFly M260 Didnt recover from an aceclearted spin although the proper controls were aplied and the cable tension was correct.


Thanx all

[Genghis the Engineer]

ABOOD13, could you post a link to the accident report of the incident to which you are referring. T67 spinning is a complex and occasionally controversial subject, but the various accidents which have happened aren't all the same.

G

[ABOOD13]

Its still clasified information until now bcz its a military A/C all what we know it was a right hand spin went into an acelerated spin without any sign to recover , and the control inputs were 100% correct.

abood13

[Genghis the Engineer]

I think that you do need to give us a lot more than that to get any kind of meaningful opinion from anybody.

G

[DB6]

Did it accelerate despite full pro-spin controls or was the stick allowed to come forward? Some power left on? Some aileron applied? Loaded outside C of G limits? I imagine you are talking about the Jordanian version which I think has an air conditioning pack in the rear. We used to spin the UK versions, normally to the left but not exclusively, normal and accelerated with no recovery problems beyond a delay in the accelerated case. Genghis is right, there is no general problem with the Firefly, you would have to be more specific.

[ABOOD13]

, if we look to what happened according to the student memory : he did the first spin , then his instructor wanted to show him another one , so entered the right spin, he applies the corrective controls but the A/C did not recover, he ordered him to abandon and the student jumbed

[man friday]

One of the JEFTS fireflies out of Barkston Heath span in 14 years ago. Best bet would be to try and contact anyone from the unit and see what info they can pass on.

The USAF had a problem with the aircraft and its spin recovery charictaristics and i remember a number of their instructors came over to Barkston to discuss the snag

[Genghis the Engineer]

Those basic facts are quite well known, and the destruction of the USAF T3a fleet was very controversial within the aviation community.

With regard to an engine stoppage causing a stall/spin - that should not happen with a trained (or even solo student) pilot; the link is not there without a reasonable degree of mishandling. I've flown a short assessment on the M260 and personally saw nothing that would cause that immediate link of engine failure = stall = spin. The aircraft did not show a large pitch change with power, nor a strong tendency to spin from a level or turning flight stall; I doubt that it would have been certified by UK CAA if it had.


Do bare in mind that single engine piston aircraft are all potentially subject to engine failures and that all pilots flying them are trained to deal with engine failures - it's a very substantial part of initial and recurrent training.


I don't deny that there may well have been some problem with the USAF T3as, but I don't believe that it's reasonable to say that any incidence of vapour locking led to spinning accidents, the link doesn't really make sense. That said, in the UK fleet, I believe that the T67 has the highest rate of stall/spin related fatal accidents, per flying hour, of the training fleet - however virtually all of those fatalities were in the smaller engined T67a and T67b models, not in the more powerful military variants which are also operating in the UK civil and military training environments.

G

[angelorange]

No British M260 variants have been lost in spinning accidents. There was an early model T67 that was spun on a training sortie and both instructor and student escaped safely. An accident report was written and published at the time.

In the USA Edwards AFB Test Pilots span the T67M260 regularly with no recovery difficulties - they even tested inverted spinning which is not permissable in UK.

[rotorfossil]

We had a share in a T67a. When flown with 2 up and the necessary low fuel load to keep within aerobatic weight limit, it was quite easy to exceed the rear CofG limit. This necessitated a complex list of seat loads and seat adjustment positions. I wonder whether such calculations were always done with the earlier models, hence the spin problems, exacerbated I suspect by incorrect recovery actions by inexperienced pilots.

[50+Ray]

Barkston Instructors have an annual training requirement to carry out a high rotational spin with Standards, in addition to the regular spin currency during CT or during instructional sorties.
I apply the same standard to instructors here. Does the RJAF?

[Genghis the Engineer]

Barkston Instructors have an annual training requirement to carry out a high rotational spin with Standards, in addition to the regular spin currency during CT or during instructional sorties.
I apply the same standard to instructors here. Does the RJAF?


The high rotational spin was a known issue on the Bulldog, does it genuinely map to the T67?

G

[50+Ray]

High rotational spin in the Bulldog was achieved simply by moving the stick forward a couple of inches from the fully back position while in a stable spin. The Firefly is a bit more reluctant - you have to go about half way forward, or centralize, before things get rapid. If a student has not put you into one yet, then you have not flown with enough of them! In my previous job I have to say it was never a problem with NCO students who treated spinning as a 'drill', but Young Rupert was known to extemporize sometimes with exciting results.
Hence - always, lightly, follow through on the controls when Bloggs is spinning. It makes for a slightly quicker 'I have control' & recovery.
Always enjoyed it, but rate of turn can make anyone dizzy!

[stump2]

This will not answer the original question; however, I had the duty of carrying the final test result briefing forward on the USAF T-3A after our team rung out the aircraft at Edwards. Our final test results on the flying (spin) characteristics were that, with proper control inputs, the T-3A recovered easily from every entry condition (errect, inverted, left, right ...). There was NO engine issue with the USAF version, although early on ground pounders insisted that there was. There was sufficient "telegraphing" of the ensuing departure/spin to recover; however, any delay in departure prevention controls led directly to a spin. Edwards results gave no indication of an unrecoverable spin mode as indicated in this thread.

STUMP

[50+Ray]

Thank you Stump. Agree entirely. :)
Ray

[ultimate1]

hi ppl
any one knows what happens to spin in firefly if u just centrlize controls and did not select oposite rudder u just leave ur controls
dose the t-67 recover to spiral or it just keep spinning ?

[Genghis the Engineer]

hi ppl
any one knows what happens to spin in firefly if u just centrlize controls and did not select oposite rudder u just leave ur controls
dose the t-67 recover to spiral or it just keep spinning ?

The short answer is that I don't know, the long answer is that this was quite likely covered in the military cert programme and there's a fair chance that the UK MoD flight test reports on the T67 may be unclassified and requestable via the public records office at Kew. I've certainly done this from outside the MoD with some Tucano spinning reports I wanted for some research work so there's a good chance.

G

[50+Ray]

The answer is that the spin becomes high rotational, and still will be when the ground breaks your fall. Just do what the book says!
Ray

[ultimate1]

thanks ray but its always good to know beond books
who wrote the book is normal pilot and not a god
and what make me aske that is that when you unstall it by stick forward or at least neutral with rudder neutral as well make it go spiral because i think it should be stalled and yawed (always) to keep spinning
or what do you think...?

[50+Ray]

The good book says "full rudder opposite to the spin(as shown by turn needle). Pause (1 Sec). Control column centrally forward until spin stops.
Move the stick progressively forward until, if necessary, it reaches the fully forward position in about 3 seconds.
I have only reached full forward once, in a T67200 which we subsequently found was right on/ pushing the edge of the C of G envelope.
Stick partly forward is not good enough! Keep it moving and the rotation WILL stop when the wing eventually unstalls.

[2close]

Not sure if this contributes to the thread but I experienced high rotational spin in a Bulldog I was flying for the first time for no other reason than the harness lock was too low down in my midriff which prevented full back stick.

Made for an interesting ride :eek: and taught me to make sure it was in the right position on the ground in future!!! Nugget!!! ;)

[longer ron]

Interesting to hear about high rotation spins in bulldogs,back in the early 80's whilst at summer camp (cosford) with a UAS,I returned from lunch to find a 'pale' looking crew.They had experienced a high rot spin and I got the job of trying to figure out why,after scratching head for a few hours and checking rigging/airframe etc...the only anomoly I could see was that the elevator tab was set a bit lower than I would normally rig it,from memory the rigging procedure was a little vague anyway and also that the setting for spinning was in 'take off range'-also a little vague.
I also set the elevator range nearer the max 'up' (it had been in the mid range)- the resultant air test gave the slowest spin in our fleet,but myself and the boss were happy that the a/c was ok.
The engo at cranners did not seem to agree that with the stick on the backstop the elev tab was merely acting as the trailing edge of the elevator and no longer a tab :rolleyes: and the a/c ended up at Shawbury for months where Marshalls could not find anything wrong with it.