AAIB investigation to Hawker Hunter T7 G-BXFI 22 August 2015
Homsap,
John Farley didn't say that AH was not negligent. He just offered a possible explanation which to me, having no FJ experience, seems the most plausible I have read on here.
Of course AH knew he was flying a Hunter. But sometimes we get distracted and 'revert to type' and am sure we can all think of many situations where that has occurred, albeit with little consequence to ourselves or others.
John Farley didn't say that AH was not negligent. He just offered a possible explanation which to me, having no FJ experience, seems the most plausible I have read on here.
Of course AH knew he was flying a Hunter. But sometimes we get distracted and 'revert to type' and am sure we can all think of many situations where that has occurred, albeit with little consequence to ourselves or others.
The notion that there was confusion between a Hunter and a JP is preposterous. The cockpits are very different, control columns are different, no brake lever on the JP totally different windscreens etc. Etc.
305 knots is WAY above the speed needed to loop a JP, it could, with care, be looped at 140 knots with the gear down, but 240, 250 knots was more than enough.
Technique on the JP was to go to full power, apply 4 g initially and then check for a straight pull by ensuring the tip tanks were equidistant from the horizon, Hunter doesn't have tip tanks and the wing tips are well behind you.
That way the recovery height could easily be above start height and the gate height WOULD be achieved, and one could also tighten the loop on the way down by pulling to the buffet or 5.5 g whichever came first and complete the loop HIGHER than start height.
As for throttle friction, another red herring, his hand would have been on the throttle during aeros and if rpm had reduced as suspected, known, there would have been a noticeable reduction in thrust, another reason to throw it away and roll out at the top.
As for confusing the start height of 190 feet for 500 feet is also preposterous for an experienced pilot, regardless of altimeter readings.
Someone mentioned the effect of age on G tolerance, it certainly is a factor. In my youth,, as a JP. QFI I could sit through max. rate turns at 5.5 G without a g suit, no problem!
In my 50s I flew a couple of trips in the Hawk, what a difference even keeping a lookout going was very hard work, even 3 g in a Spitfire recently felt very different !
Sorry guys, the suggestion of confusion is impossible , for me at least, to swallow.
305 knots is WAY above the speed needed to loop a JP, it could, with care, be looped at 140 knots with the gear down, but 240, 250 knots was more than enough.
Technique on the JP was to go to full power, apply 4 g initially and then check for a straight pull by ensuring the tip tanks were equidistant from the horizon, Hunter doesn't have tip tanks and the wing tips are well behind you.
That way the recovery height could easily be above start height and the gate height WOULD be achieved, and one could also tighten the loop on the way down by pulling to the buffet or 5.5 g whichever came first and complete the loop HIGHER than start height.
As for throttle friction, another red herring, his hand would have been on the throttle during aeros and if rpm had reduced as suspected, known, there would have been a noticeable reduction in thrust, another reason to throw it away and roll out at the top.
As for confusing the start height of 190 feet for 500 feet is also preposterous for an experienced pilot, regardless of altimeter readings.
Someone mentioned the effect of age on G tolerance, it certainly is a factor. In my youth,, as a JP. QFI I could sit through max. rate turns at 5.5 G without a g suit, no problem!
In my 50s I flew a couple of trips in the Hawk, what a difference even keeping a lookout going was very hard work, even 3 g in a Spitfire recently felt very different !
Sorry guys, the suggestion of confusion is impossible , for me at least, to swallow.
Anyone had a hard read through of Appendix H (the flight tests).
I'm struggling a bit with the comments that:
But on the TP flying bent loops the report states "The pull-ups were flown in light buffet throughout " (so presumably this was what was meant by max performance and was perhaps the TPs only way of replicating the accident manouever "numbers")
Why would anyone entering the botttom of a vertical manouevre at low level knowingly low on energy deliberately fly the pich up from the get go manoeuver in the buffet?
I'm struggling a bit with the comments that:
The 'bent' loop tests indicated that the apex height and airspeed of the accident manoeuvre was consistent with a maximum performance pull-up from 300 KIAS with significantly less than full thrust and with a 45-90 bend initiated approximately 5 seconds after pull-up They also showed that the apex height for a 'bent' loop was 300 - 400 ft less than for a straight loop when all of the other parameters remained constant.
Why would anyone entering the botttom of a vertical manouevre at low level knowingly low on energy deliberately fly the pich up from the get go manoeuver in the buffet?
Last edited by wiggy; 9th Mar 2017 at 15:20.
Sorry guys, the suggestion of confusion is impossible , for me at least, to swallow
I note from the report,
The AAIB was not able to obtain a comprehensive insight into the use of gate heights by display pilots. However, two pilots other than the accident pilot, who had relevant military and fast jet experience and were interviewed in the course of the investigation, volunteered that they had used an incorrect gate height during a display, or omitted to check a gate height
Join Date: Oct 2015
Location: UK
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Silly question - if AH thought there was a problem with the altimeter or ASI could he have made adjustments mentally. ie if he believed it was under reading by a few hundred feet, made a mental adjustment to compensate.
Only asking as there appears to be no questioning any other pilot that had flown the aircraft in the last 2-3 months as to whether they had experienced malfunctions or had tech issues with the aircraft and if so had they reported them to the maintenance company either verbally or in writing.
Only because say for the last flight AH had undertaken in BXFI the altimeter had been under reading by 500ft or so and had now been 'fixed' but nothing recorded AH may have added the extra to compensate. Which would mean he thought he had reached the min gate height.
Also, how easy is it for a Hunter pilot to tell if the throttle is not performing at full thrust. Could AH easily tell by the feel/sound and speed at the time without even looking at the instruments.
I agree the maintenance companies since 2010 need questioning more and a more in depth audit of them is required, I doubt very much that any of them have qualified aircraft personnel working for them. My understanding of the historic jet society is most of it is undertaken by aircraft enthusiasts with little or no aircraft back-grounds.
Only asking as there appears to be no questioning any other pilot that had flown the aircraft in the last 2-3 months as to whether they had experienced malfunctions or had tech issues with the aircraft and if so had they reported them to the maintenance company either verbally or in writing.
Only because say for the last flight AH had undertaken in BXFI the altimeter had been under reading by 500ft or so and had now been 'fixed' but nothing recorded AH may have added the extra to compensate. Which would mean he thought he had reached the min gate height.
Also, how easy is it for a Hunter pilot to tell if the throttle is not performing at full thrust. Could AH easily tell by the feel/sound and speed at the time without even looking at the instruments.
I agree the maintenance companies since 2010 need questioning more and a more in depth audit of them is required, I doubt very much that any of them have qualified aircraft personnel working for them. My understanding of the historic jet society is most of it is undertaken by aircraft enthusiasts with little or no aircraft back-grounds.
Posted by Homsap
page 12 Para 1.51 of the report
Licence: Airline Transport Pilot’s Licence / Private Pilot’s Licence
Aircraft Rating: Aircraft Type Rating Exemption3
valid to 27 August 2015
Medical Certificate: Class 1 medical certificate valid to 31 January 2016
The CAA real have lost the plot. The minimun qualification for a fast jet display pilot should be they hold or have held an ATPL, class one medical every six months regardless of age. You have a point regarding G forces and I'm not sure if there is research on this, but I do wonder if G forces is an issue with age.Tthere was no mention of corrective vision in the report which is odd, as I would imagine most people over fifty needs some form of corrective vision.
Licence: Airline Transport Pilot’s Licence / Private Pilot’s Licence
Aircraft Rating: Aircraft Type Rating Exemption3
valid to 27 August 2015
Medical Certificate: Class 1 medical certificate valid to 31 January 2016
Wiggy,
Appendix H states the altitudes, AUM and density altitudes of all tests flown. 'Flown in light buffet' is equivalent to a 'maximum performance pull up'. The best instantaneous turn/pitch rate is achieved when flying in light buffet in a Hunter.
Appendix H states the altitudes, AUM and density altitudes of all tests flown. 'Flown in light buffet' is equivalent to a 'maximum performance pull up'. The best instantaneous turn/pitch rate is achieved when flying in light buffet in a Hunter.
LOMCEVAK
Understand the above, though it's probably more the instantaneous vs. sustained manoeuver cpabaility in the vertical I'm intersted in - I'm certainly aware that pulling to the light buffet ( or on some types a tgt AOA) will certainly give you best instantaneous rate but I know that it's probable/possible on many types you'll end up bleeding energy off holding the said buffet ....now if you are "energy rich" at the start of the manoeuver I guess that's OK but if entering low on energy to start with on a Hunter is it a sensible thing to knowingly do? I haven't done low level aeros so I'll throw that one open to the team.
Anyhow I'll go and have another look at the Appendix.
Understand the above, though it's probably more the instantaneous vs. sustained manoeuver cpabaility in the vertical I'm intersted in - I'm certainly aware that pulling to the light buffet ( or on some types a tgt AOA) will certainly give you best instantaneous rate but I know that it's probable/possible on many types you'll end up bleeding energy off holding the said buffet ....now if you are "energy rich" at the start of the manoeuver I guess that's OK but if entering low on energy to start with on a Hunter is it a sensible thing to knowingly do? I haven't done low level aeros so I'll throw that one open to the team.
Anyhow I'll go and have another look at the Appendix.
Last edited by wiggy; 9th Mar 2017 at 16:11.
Join Date: Nov 2016
Location: Cumbria
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
Widger....
I appreciate AH exceeded what I would expect to be a reasonable licence, medical and hours criteria, the comment was made towards the CAA as a regulator in that they felt at the time, that KW (Gnat accident G-TIMM) was suitably qualified, experienced and felt that a class two medical was suitable for display flying a JP or Gnat. It also raises questions that display organisations would even consider someone relatively little experience.
I appreciate AH exceeded what I would expect to be a reasonable licence, medical and hours criteria, the comment was made towards the CAA as a regulator in that they felt at the time, that KW (Gnat accident G-TIMM) was suitably qualified, experienced and felt that a class two medical was suitable for display flying a JP or Gnat. It also raises questions that display organisations would even consider someone relatively little experience.
Join Date: Apr 2004
Location: wales
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
BVCU
"so where now would they find the expertise now ? "
How about Bristol, were the design team, tech support and incident investigation was based, EK was just an overhaul facility, all operational issues and investigation was (and still is) carried out from Bristol. RR are probably the only organisation with access to engine performance data. I think this was demonstrated on the appendix to the report
"so where now would they find the expertise now ? "
How about Bristol, were the design team, tech support and incident investigation was based, EK was just an overhaul facility, all operational issues and investigation was (and still is) carried out from Bristol. RR are probably the only organisation with access to engine performance data. I think this was demonstrated on the appendix to the report
Join Date: Jan 2008
Location: UK
Age: 69
Posts: 292
Likes: 0
Received 0 Likes
on
0 Posts
Hi Hebog looking at your forum profile I suspect that you're not an aviator but maybe have some personal connection with this tragedy. No, your question isn't "silly" in the least.
Altimeter -- This simply measures atmospheric pressure just like a barometer at home. But instead of being calibrated in inches of mercury or millibars, the display is calibrated in feet of altitude. It's a linear relationship near ground level up to many thousands of feet. However, when we say 'altitude' we have to ask "altitude above WHAT?". The hills? The sea level? The runway?
For this reason an aircraft altimeter has an adjuster knob. When the pilot is about to start his engines he asks the control tower for the actual pressure on the airfield, in millibars. He then dials that setting into the altimeter and he expects it to read (nearly) zero. If it doesn't, he will not fly because the altimeter is the second most important instrument he has. Airspeed is arguably more important. This is drummed into student pilots from their very first lesson -- it is inconceivable that anyone would fly unless their altimeter zeroed on the airfield. It gets a little bit more involved after the pilot takes off but I think you can safely assume that the altimeter zeroed fine at take-off. This aircraft had two altimeters and there was a small difference between them but not a significant difference. -- There is no reason to think that the small difference had any bearing on the accident.
To answer your specific question whether the pilot could or would have mentally compensated for an altitude error the answer is NO. The pilot would adjust the altimeter, not carry out mental adjustments. Why would he? He has a knob he can use to set it to whatever he likes.
Sorry I can't help you with your other questions. I'm sure an experienced display pilot will help to explain.
Altimeter -- This simply measures atmospheric pressure just like a barometer at home. But instead of being calibrated in inches of mercury or millibars, the display is calibrated in feet of altitude. It's a linear relationship near ground level up to many thousands of feet. However, when we say 'altitude' we have to ask "altitude above WHAT?". The hills? The sea level? The runway?
For this reason an aircraft altimeter has an adjuster knob. When the pilot is about to start his engines he asks the control tower for the actual pressure on the airfield, in millibars. He then dials that setting into the altimeter and he expects it to read (nearly) zero. If it doesn't, he will not fly because the altimeter is the second most important instrument he has. Airspeed is arguably more important. This is drummed into student pilots from their very first lesson -- it is inconceivable that anyone would fly unless their altimeter zeroed on the airfield. It gets a little bit more involved after the pilot takes off but I think you can safely assume that the altimeter zeroed fine at take-off. This aircraft had two altimeters and there was a small difference between them but not a significant difference. -- There is no reason to think that the small difference had any bearing on the accident.
To answer your specific question whether the pilot could or would have mentally compensated for an altitude error the answer is NO. The pilot would adjust the altimeter, not carry out mental adjustments. Why would he? He has a knob he can use to set it to whatever he likes.
Sorry I can't help you with your other questions. I'm sure an experienced display pilot will help to explain.
Join Date: Jul 2008
Location: Planet Ix
Posts: 804
Likes: 0
Received 0 Likes
on
0 Posts
but if entering low on energy to start with on a Hunter is it a sensible thing to knowingly do? I haven't done low level aeros so I'll throw that one open to the team.
I used to practice low level loops in a 102 series Avon Hunter and I can confirm the following.
500ft AGL entry, 300kts, 1 notch of flap, full internal fuel and application of full power throughout results in a very comfortable recovery about 800ft AGL. In the aircraft I was flying anyway.
it does need sympathetic handling, as pulling to heavy buffet in the pull up, or less than max thrust obviously results in a degraded recovery height. I used to practice that, as it was my bottom line for loop entry.
it is possible to loop slower, but I wouldn't advise it at low level.
Join Date: Jan 2008
Location: Hotel Sheets, Downtown Plunketville
Age: 76
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
At 12:00 Hrs on 3 March, Sussex Police released a press notice announcing they will be looking at the report in detail with their independent experts and do to everything they can to submit a file to the CPS in advance of the pre-inquest review on June 20.
The full text of the press release is at :
https://sussex.police.uk/news/sussex...ham-air-crash/
The full text of the press release is at :
https://sussex.police.uk/news/sussex...ham-air-crash/
Lemain - oh, dear...
Do you seriously believe that the term altitude can relate to any of those datums?
However, when we say 'altitude' we have to ask "altitude above WHAT?". The hills? The sea level? The runway?
At 12:00 Hrs on 3 March, Sussex Police released a press notice announcing they will be looking at the report in detail with their independent experts and do to everything they can to submit a file to the CPS in advance of the pre-inquest review on June 20.
The full text of the press release is at :
https://sussex.police.uk/news/sussex...ham-air-crash/
The full text of the press release is at :
https://sussex.police.uk/news/sussex...ham-air-crash/
Sika
it does need sympathetic handling, as pulling to heavy buffet in the pull up, or less than max thrust obviously results in a degraded recovery height. I used to practice that, as it was my bottom line for loop entry.
it is possible to loop slower, but I wouldn't advise it at low level.
Makes sense, many thanks.
it does need sympathetic handling, as pulling to heavy buffet in the pull up, or less than max thrust obviously results in a degraded recovery height. I used to practice that, as it was my bottom line for loop entry.
it is possible to loop slower, but I wouldn't advise it at low level.
Join Date: Jul 2008
Location: Planet Ix
Posts: 804
Likes: 0
Received 0 Likes
on
0 Posts
treadigraph:
Min 3800 ft, speed above 110kts unloaded. 4000ft+ usually achieved.
Basically the Hunter at these weights has sufficient power for the manoeuvre, so wherever you find yourself, as long as you haven't washed energy off needlessly on the way up and keep pushing energy in, if it goes over the top, it will come out the bottom at or better than your entry height. If it looks like you aren't going to go over the top because you are too slow, you can always use the old combat manoeuvre of dropping flap 4 to help the nose down, unload and roll out when the nose is below the horizon again.
Its not like flying something like a small engined Slingsby T67, Fuji or 150 aerobat where you loose energy in the overall manoeuvre, no matter how you fly it.
The Hunter is without reservation, the most beautiful machine I have ever flown, and is almost (but not totally) vice-less. The initial design and subsequent development produced something that make it an amazing pilot's machine.
Sika, what height/speed would you be looking for over the top?
Basically the Hunter at these weights has sufficient power for the manoeuvre, so wherever you find yourself, as long as you haven't washed energy off needlessly on the way up and keep pushing energy in, if it goes over the top, it will come out the bottom at or better than your entry height. If it looks like you aren't going to go over the top because you are too slow, you can always use the old combat manoeuvre of dropping flap 4 to help the nose down, unload and roll out when the nose is below the horizon again.
Its not like flying something like a small engined Slingsby T67, Fuji or 150 aerobat where you loose energy in the overall manoeuvre, no matter how you fly it.
The Hunter is without reservation, the most beautiful machine I have ever flown, and is almost (but not totally) vice-less. The initial design and subsequent development produced something that make it an amazing pilot's machine.
