Wikiposts
Search
Flight Testing A forum for test pilots, flight test engineers, observers, telemetry and instrumentation engineers and anybody else involved in the demanding and complex business of testing aeroplanes, helicopters and equipment.

FireFly Spin

Thread Tools
 
Search this Thread
 
Old 4th Jun 2009, 17:08
  #1 (permalink)  
Thread Starter
 
Join Date: Jun 2009
Location: M.E
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
FireFly Spin

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
ABOOD13 is offline  
Old 4th Jun 2009, 17:42
  #2 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,212
Received 48 Likes on 24 Posts
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
Genghis the Engineer is offline  
Old 5th Jun 2009, 11:00
  #3 (permalink)  
Thread Starter
 
Join Date: Jun 2009
Location: M.E
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
Firefly spin

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
ABOOD13 is offline  
Old 5th Jun 2009, 13:33
  #4 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,212
Received 48 Likes on 24 Posts
I think that you do need to give us a lot more than that to get any kind of meaningful opinion from anybody.

G
Genghis the Engineer is offline  
Old 6th Jun 2009, 00:27
  #5 (permalink)  
DB6
 
Join Date: Apr 1999
Location: Dundee, Scotland
Age: 61
Posts: 1,271
Likes: 0
Received 0 Likes on 0 Posts
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.
DB6 is offline  
Old 7th Jun 2009, 11:36
  #6 (permalink)  
Thread Starter
 
Join Date: Jun 2009
Location: M.E
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
, 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

Last edited by ABOOD13; 12th Jun 2009 at 06:25.
ABOOD13 is offline  
Old 7th Jun 2009, 16:35
  #7 (permalink)  
 
Join Date: Apr 2005
Location: The land that taste forgot
Posts: 199
Likes: 0
Received 0 Likes on 0 Posts
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
man friday is offline  
Old 9th Jun 2009, 17:26
  #8 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,212
Received 48 Likes on 24 Posts
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
Genghis the Engineer is offline  
Old 17th Jun 2009, 06:33
  #9 (permalink)  
 
Join Date: Dec 2002
Location: Europa
Posts: 612
Likes: 0
Received 0 Likes on 0 Posts
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.
angelorange is offline  
Old 18th Jun 2009, 09:24
  #10 (permalink)  
 
Join Date: Nov 2001
Location: Norfolk
Age: 84
Posts: 298
Likes: 0
Received 0 Likes on 0 Posts
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.
rotorfossil is offline  
Old 18th Jun 2009, 10:51
  #11 (permalink)  
 
Join Date: Sep 2003
Location: Back in Blighty
Age: 73
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
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?
50+Ray is offline  
Old 18th Jun 2009, 13:04
  #12 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,212
Received 48 Likes on 24 Posts
Originally Posted by 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?

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

G
Genghis the Engineer is offline  
Old 19th Jun 2009, 09:10
  #13 (permalink)  
 
Join Date: Sep 2003
Location: Back in Blighty
Age: 73
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
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!
50+Ray is offline  
Old 23rd Jun 2009, 05:02
  #14 (permalink)  
 
Join Date: Aug 2001
Location: home
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
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
stump2 is offline  
Old 23rd Jun 2009, 10:20
  #15 (permalink)  
 
Join Date: Sep 2003
Location: Back in Blighty
Age: 73
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
Thank you Stump. Agree entirely.
Ray
50+Ray is offline  
Old 25th Jun 2009, 21:28
  #16 (permalink)  
 
Join Date: Jun 2009
Location: jordan
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
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 ?
ultimate1 is offline  
Old 26th Jun 2009, 12:20
  #17 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,212
Received 48 Likes on 24 Posts
Originally Posted by 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 ?
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
Genghis the Engineer is offline  
Old 26th Jun 2009, 17:58
  #18 (permalink)  
 
Join Date: Sep 2003
Location: Back in Blighty
Age: 73
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
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
50+Ray is offline  
Old 26th Jun 2009, 23:37
  #19 (permalink)  
 
Join Date: Jun 2009
Location: jordan
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
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...?
ultimate1 is offline  
Old 27th Jun 2009, 15:31
  #20 (permalink)  
 
Join Date: Sep 2003
Location: Back in Blighty
Age: 73
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
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.
50+Ray is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.