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AAIB investigation to Hawker Hunter T7 G-BXFI 22 August 2015

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AAIB investigation to Hawker Hunter T7 G-BXFI 22 August 2015

Old 12th Mar 2017, 18:54
  #481 (permalink)  
 
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Originally Posted by falcon900 View Post
From page 43 of the report: "The aircraft took off from North Weald Airfield at 1204 hrs. The pilot occupied the left seat. Cockpit video indicates rotation was initiated at 112 KIAS. The pitch attitude was subsequently reduced and then increased again before the aircraft lifted off the runway."

Would this be normal for a Hunter takeoff?
No (already discussed earlier in the thread).
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Old 12th Mar 2017, 19:36
  #482 (permalink)  
 
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Sorry, I must have missed it.
Seems odd that it wasn't developed by the AAIB, as it could indicate that the pilot wasn't on top form, or that there wasn't as much thrust as he thought.....
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Old 12th Mar 2017, 20:02
  #483 (permalink)  
 
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or thought that he was in a JP ............. we keep skirting this one, do we not?
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Old 12th Mar 2017, 20:16
  #484 (permalink)  
 
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Originally Posted by falcon900 View Post
Sorry, I must have missed it.
Seems odd that it wasn't developed by the AAIB, as it could indicate that the pilot wasn't on top form, or that there wasn't as much thrust as he thought.....
Or that, with the reported 14 kt tailwind at North Weald, he could see the end of the runway approaching and thought that getting airborne might be a good idea ...

All that the AAIB had to say about that was:

"The aircraft departed at 1204 hrs. The takeoff run was longer than usual due to the high air temperature and tailwind, and the pilot raised the nose of the aircraft to begin the lift-off at 112 KIAS instead of the 120 KIAS he would use normally. Once airborne, the aircraft flew towards the south coast east of Shoreham."
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Old 12th Mar 2017, 21:17
  #485 (permalink)  
 
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Let's put the liftoff "error" to bed now. This one is very simple. The runway is, to use an understatement, not the most even, indeed last time I took off from there in a Hunter I thought I would need a dental appointment after the flight!

Standard technique is to lift the nose wheel off the ground about 110-120kts, check and then she will fly airborne when ready. Watch the numerous formation takeoffs on YouTube and enjoy.The Hunter doesn't do V1, Rotate, V2, yet amazingly it still flies!

The report accurately says he commenced rotation at 112 kts (I consider that a normal speed) , not liftoff. Liftoff would have occurred 10 or so seconds later about 135 kts. Any over rotation due to bumps would need to be corrected.

No amazing proof of incompetence or a gash approach here. Quite the opposite as getting the nose wheel off the ground as soon as possible would reduce vibrations and aid reading instruments!
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Old 12th Mar 2017, 21:50
  #486 (permalink)  
 
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It has been commented that the AAIB report is inconclusive. That is incorrect. In its summary it has identified six factors. The main elements of these are:

The first three refer to the escape manoeuvre and the pilot`s perception or realisation, training and practice in that respect. The fourth and the fifth is the pilot taking the aircraft on a changed ground track which placed the exit from the manoeuvre along a public highway. The last one is why so many lost their lives. Basically to me it reads that had he bodged it along the display axis, instead of where he actually did so many lives would not have been lost. The so called "severity of outcome".

Can it be any clearer than that.
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Old 13th Mar 2017, 00:34
  #487 (permalink)  
 
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It's not quite as straightforward as that.

Contributory factor 5 was that "The manoeuvre took place above an area occupied by the public over which the organisers of the flying display had no control".

But that would have been the case even had the display been flown exactly as planned, rather than being a consequence of going off-track - there is no way that a fast jet display routine is going to stay within the airfield boundary at a location like Shoreham.
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Old 13th Mar 2017, 12:08
  #488 (permalink)  
 
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Quote sh:
Let's put the liftoff "error" to bed now. This one is very simple.
Unfortunately, the report makes no attempt to fully analyse the takeoff. The merit of the choice of direction for runway slope and weather conditions are not explored nor the achieved performance of the aeroplane. Strange, in a scenario where the lack of performance of the aeroplane was possibly a major factor in the deaths of 11 people 25 mins later.
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Old 13th Mar 2017, 13:39
  #489 (permalink)  
 
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I do think the takeoff requires further consideration, not least because of the AAIB comment on page 8 that the rotation was initiated at 112 rather than the pilots "usual" 120 knots. I have already queried the fact he raised the nose, had to lower it, before then raising it again to take off. I hear what is being said about bumps in the runway, but taken together with the lower than "usual" speed, I cant help but wonder if there was something else adrift here, affecting any, or all of, the information being provided to the pilot, his perception of his situation, and the thrust being delivered by the engine.
Since these seem to be the same factors at play during the accident, I would have expected to see more about the takeoff in the report.
Turning to the analysis of the accident manoeuvre itself, two things seem striking in relation to engine thrust (figure 15 page 53): firstly the engine rpm REDUCE during the climb phase. Even if the pilot thought he was flying a JP, he wouldn't reduce power during this phase.
Secondly, rpm increase after the apex, which would suggest that he was attempting a recovery of sorts.
The key question seems to me to be what caused the dramatic reduction in rpm during the climb.
For the sake of completeness, I am surprised also that the report did not address the Southend JP matter for any relevant clues.
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Old 13th Mar 2017, 16:06
  #490 (permalink)  
 
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Falcon900 and Onceapilot:

I do think the takeoff requires further consideration, not least because of the AAIB comment on page 8 that the rotation was initiated at 112 rather than the pilots "usual" 120 knots.
To be pedantic, 112 kts was IAS. Nobody knows what the TAS was. Nobody knows what the GS was.
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Old 13th Mar 2017, 16:48
  #491 (permalink)  
 
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This has to be a joke post!
At the great height of North Weald at 321amsl, and assuming 25C, the TAS is very marginally higher than the IAS: specifically TAS was 115Kts, and the ground speed is not relevant to Lift Off!
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Old 13th Mar 2017, 17:09
  #492 (permalink)  
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Good grief. As far as I remember (and it was nearly 30 years ago that I flew that T7), standard technique was to pull fully back at about 110kts then relax the pull as the nosewheel lifted off. Just what the T/O has to do with the subsequent crash is beyond me!
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Old 13th Mar 2017, 17:14
  #493 (permalink)  
 
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Originally Posted by terry holloway View Post
This has to be a joke post!
At the great height of North Weald at 321amsl, and assuming 25C, the TAS is very marginally higher than the IAS: specifically TAS was 115Kts, and the ground speed is not relevant to Lift Off!
Instrument error.
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Old 13th Mar 2017, 17:41
  #494 (permalink)  
 
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Originally Posted by terry holloway View Post
and the ground speed is not relevant to Lift Off!
True - all it tells you is how fast the end of the runway is approaching.
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Old 13th Mar 2017, 18:08
  #495 (permalink)  
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Originally Posted by Lemain
Instrument error.
Let's hope nobody thinks that inreplying to a post that mentions IAS and TAS, you might be suggesting that instrument error is the difference between them, else we might be in for some long discussion
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Old 13th Mar 2017, 20:52
  #496 (permalink)  
 
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Quote from DavidReid UK :

"there is no way that a fast jet display routine is going to stay within the airfield boundary at a location like Shoreham."

I would accept but the CAA might not. As is the case with Safety Recommendation 2016-039. See pages 175-181 of the AAIB report.
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Old 13th Mar 2017, 22:37
  #497 (permalink)  
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Ideally, the nosewheel should be eased off the ground between 115 and 135 knots depending on configuration.However, on some aircraft, with the CG well forward, it may prove impossible to lift the nosewheel within this speed band. Under the worst conditions of CG and rigging tolerances, it may be neccessary to attain 150 knots before the nosewheel can be lifted.

That's word for word, including the spelling mistake, from the (how to fly a hunter) manual.
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Old 13th Mar 2017, 23:06
  #498 (permalink)  
 
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Originally Posted by Chronus View Post
Quote from DavidReid UK :

"there is no way that a fast jet display routine is going to stay within the airfield boundary at a location like Shoreham."

I would accept but the CAA might not.
The CAA clearly agree that it's impossible too, hence their rejection of the AAIB's recommendation that aerobatics should only take place over a sterile area.
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Old 13th Mar 2017, 23:21
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Does it matter? And even if he did have problems on take-off doesn't that mean he should have been extra careful during the final manoeuvre?

The fact is that he arrived at the top of that manoeuvre too low and too slow. Regardless of any possible malfunctions of the aircraft he should have recognised this and rolled out, not attempted to carry on. Short of any incapacity he may have suffered on the day (which cannot be ascertained due to him being placed in a coma) it does rather look as it is pilot error due to the simple fact that he didn't abort the manoeuvre by rolling out at the top. OK, he didn't practise such a 'plan B', but that again is, IMHO, pilot error.

As far as I can see the only thing that would have made this not pilot error is if he suffered some sort of medical 'event', but unfortunately it looks like that, even if it occurred, cannot be determined one way or the other.
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Old 14th Mar 2017, 07:34
  #500 (permalink)  
 
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I am astounded by some of the continued comments about the take off. Some people obviously have agendas and are unwilling to allow facts and knowledge interfere with them. He does not seem in any way confused here.

To be as clear as I can, as a pilot who was on a Hunter squadron many years ago, and was current Hunter until this accident happened, the information available about the take off rotate technique seems perfectly normal to me. He did not apply a technique applicable to an airliner, JP or light aircraft. It was the correct Hunter technique. Including raising the nose speed.

Perhaps, just perhaps, that is why the AAIB has not made a meal of it?
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