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Hawker Hunter Crash at Shoreham Airshow

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Hawker Hunter Crash at Shoreham Airshow

Old 22nd Sep 2015, 15:29
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Hello sharpend, quote:
"Chris, with regard to your comment 'while still inverted after going over the top he became committed' I'm sure that if he realised he was in trouble, he would have rolled the right way up and aborted the manoeuvre. Thus he was either incapacitated or unaware of the danger."

Yes. In fact I was deliberately vague regarding the point at which rolling the right way up was no longer an escape option. I wrote: "...at some point while still inverted after going over the top he became committed to completing a looping manoeuvre."

At the beginning of what I described as the intermediate segment of the descent (with low pitch-rate) that option was still available, IMHO. So, unless there was a control problem, the low pitch-rate and not rolling upright can only be explained by your assertion above, which seems to cover the unintentional (incapacitation) and the intentional (over-estimation of height).

Can you fast-jet/aerobatic experts help me lay one remote possibility to rest? Early in this discussion, I posted an observation about the dimensions of the Shoreham paved runway. IIRC, it's about a third of the width of a standard (instrument) runway and about half as long. Would it have been visible from the cockpit as the a/c was inverted and going over the top? And does my suggestion that the pilot might have been dazzled by the sun (in the south) and momentarily unable to read his altimeter make any sense?

Last edited by Chris Scott; 22nd Sep 2015 at 16:17. Reason: First sentence of last para extended.
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Old 22nd Sep 2015, 18:25
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Chris Scott
I posted an observation about the dimensions of the Shoreham paved runway. IIRC, it's about a third of the width of a standard (instrument) runway and about half as long.
You could of course look it up Sir

SHOREHAM AERODROME CHART - ICAO



Would it have been visible from the cockpit as the a/c was inverted and going over the top?
Of course to his port side, for positioning purposes

And does my suggestion that the pilot might have been dazzled by the sun (in the south) and momentarily unable to read his altimeter make any sense?
Not really - dazzle is a hazard but does not stop you flying the aircraft

Disorientation is perhaps a separate aeromedical consideration

He approached into a high sun, rolled such that the sun came through his port side and after that the sun would have been a constant

1 visor later or a pair of sunnies and the sun would be a managed issue

It is an aeromedical fact that flying into sun and reading instrument data in house is a potential hazard. All experienced pilots are aware of this. Hence many checks on the run in before the sun might have played a part.
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Old 22nd Sep 2015, 19:29
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Chris Scott
Would it have been visible from the cockpit as the a/c was inverted and going over the top?
The airport in this instance would have been behind the pilot and all but impossible to see when going over the top inverted. At this point, you rely on landmarks somewhat below and out in front (directly away from the airport) to correct if necessary so as to be on line as you pull through into the vertical on the backside of the loop. The longer the runway, the slower the airplane, the quicker the runway itself becomes the reference for line and height (in a motor-powered glider, I was never not over the runway; the only concern was not drifting or angling over the deadline). In this case, short runway, fast airplane.

The actual dimensions of the runway do have to be taken into account when visually judging height during the pullout. This one was relatively short and narrow.
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Old 23rd Sep 2015, 08:01
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Courtney... I agree all your comment Point taken.

Of course if you read my comments you will see that Andy is, not was... We wish him well and whatever his injuries, we hope he makes a full and speedy recovery.

And of course there could be a hundred mechanical reasons that led to this terrible accident. I personally am always concerned about loose articles and have found lots in Club aeroplanes, all of which could have resulted in jammed controls and an accident.

We just have to wait until ALL the facts are known.
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Old 23rd Sep 2015, 08:22
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With you there, Sharpend.
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Old 24th Sep 2015, 09:11
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Hi Reheat On,
Thanks for your insights on managing sunlight during aeros - rather more complex considerations than in an airliner cockpit. (We used to use the Daily Telegraph on the Afrika Corps in my youth, if the stick-on meal-tray lining wasn't big enough).

I now realise that the sun would have been well under the port side at the top of the manoeuvre, so perhaps not a dazzle factor at that point? As you seem to imply, disorientation can affect any of us without warning, for example during sudden head movements.

That link to the Shoreham aerodrome chart doesn't work for me. The only paved runway dimension I could get before my original post was the runway length, so I assessed the width by measuring it on the satellite picture. Its proportions are not dissimilar from a 10,000-foot instrument runway. But I'm not suggesting that a runway is the only visual cue to height assessment, as Cows Getting Bigger might remind me.
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Old 24th Sep 2015, 09:35
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Airfield chart included:

Pilot Information for Aerodrome Operations 25th May to 12th June 2015
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Old 24th Sep 2015, 13:15
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Thanks ORAC,

18m x 1036m makes it roughly two-fifths (40%) of the width and length of a typical provincial airport runway, such as Turnhouse's 06/24 (46m x 2556m). Many main runways at RAF master aerodromes would be comparable with Turnhouse 06/24, I think.
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Old 24th Sep 2015, 15:47
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18m x 1036m makes it roughly two-fifths (40%) of the width and length of a typical provincial airport runway, such as Turnhouse's 06/24 (46m x 2556m).

If I may raise a point of order on a very serious thread, and whilst I readily accept the technical point regarding runway length and width, Turnhouse should not be described as a provincial airport, since it serves the capital of Scotland, by definition the very antithesis of a province.

Glasgow on the other hand.....

Jack
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Old 24th Sep 2015, 17:05
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Originally Posted by Chris Scott
But I'm not suggesting that a runway is the only visual cue to height assessment
I wouldn't suggest that either. The top gate is measured using the altimeter, not visual cues. On the way down the altimeter is the main gauge too until the very late stages; even then it's the King. I think I see where you're going with this, but I would consider it unlikely. Interesting thinking, though.
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Old 24th Sep 2015, 20:34
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Trim Stab, I don't think CM ever picked an argument with you. He just told you that you were wrong to take the debate in that direction at this stage. If he hadn't, I would have.

Yes, the decent is within the bounds of what little is know of his DA from the document you quote for reasons that have already been covered here.

You can be as interested as you like in any legal process, but going on line and saying you wonder if the pilot might be persecuted is rather like going to a F1 race and saying that you wonder if you might see someone crash - simply distasteful and pointless as you have already answered your own question. Investigations, Police, CPS. If you knew all that, why ask?
It still seems to me a perfectly legitimate question to ask why he started to pull up into a vertical aerobatic manouvre at 45 degree to the display line at 200ft.

The AAIB report describes his DA as:

a valid Display Authorisation (DA), issued by the UK CAA, to display the Hawker Hunter to a minimum height of 100 ft during flypasts and 500 ft during Standard category aerobatic manoeuvres.
Cap 403 describes Standard category aerobatics as:

6.1 Standard aerobatic displays
 Lines – Mainly horizontal or up to 45 climbing/diving lines in normal flight.
 Turns – Turns through 90 to 360 in normal flight.
 Spins – Erect Spins of one turn, with entry and exit in normal flight.
 Stall Turns – Stall turns with normal entry and exit.
 Loops and Eights – Inside circular loops with normal entry and exit.
 Combinations – Half an inside loop followed by a half roll (‘Roll off the Top’.) Five eighths of an inside loop combined with a half roll on diving exit Line (‘Half Cuban 8’). 45 climbing line followed by a half roll and pull through to level flight (‘Reverse Half Cuban 8’)
 Rolls – Slow, aileron or barrel rolls on horizontal line, or where combined with a combination manoeuvre listed above, on the diving or climbing line.
To quote from the AAIB preliminary report:

executing a Derry turn2 to the left and then commenced a descending left turn to 200 ft amsl, approaching the display line at an angle of about 45o. The aircraft then pitched up into a manoeuvre with both a vertical component and roll to the left, becoming almost fully inverted at the apex of the manoeuvre at a height of approximately 2,600 ft amsl.
So was his trajectory at 200ft at 45 deg to display line a "low pass"? Or was it the start of a Standard category aerobatic manoeuvre, below his DA of 500ft?
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Old 24th Sep 2015, 21:09
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500 ft is for recovery from aerobatics. It does not matter what height they are started from - provided the gate is for recovery at the stipulated height.

The military do exactly the same thing - not that there are that many now, but most arrive at 100 ft and then pull up into a manoeuvre.

RAF Typhoon Display Team - Display Sequence
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Old 24th Sep 2015, 22:18
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Getting a bit low one day in a glider, I looked for potential places to land, in case I continued not finding any lift.

Right below was a lovely looking airstrip. But too small. It was for models. I wasn't fooled. And I didn't need a glance at the altimeter to save me from being fooled.

I seriously do not believe that someone's height perception is primarily derived from the perceived dimensions of the runway.

This pilot would have flown displays at a variety of sites in the previous days, some airfields some not, and several by the coast.
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Old 24th Sep 2015, 22:47
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I personally am always concerned about loose articles and have found lots in Club aeroplanes
I always have a very good poke around any aircraft also. Only the other day I found a French loaf underneath the pax/co pilots seat and I kid you not.

I seriously do not believe that someone's height perception is primarily derived from the perceived dimensions of the runway.
Neither do I. I've never bought the 'narrow/wide/short/long' argument. If you don't know what a thousand or five hundred foot above the ground looks like then it's time to hang up the flying boots.
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Old 25th Sep 2015, 09:25
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Trim Stab

So was his trajectory at 200ft at 45 deg to display line a "low pass"? Or was it the start of a Standard category aerobatic manoeuvre, below his DA of 500ft?
I think you are banging the wrong drum here. If the vertical trajectory was more than 30 deg nose up at 200 ft you might have a point, but the issue is
the stage at which a manoeuvre becomes aerobatic. If you keep aileron applied you will keep rolling (= aerobatics) but if you stop the input after 45 deg, so will the roll (= normal turn). Same with pitch, however rapid. A 4g pitch to 30 deg nose up is not aerobatic. If, as is commonly done, you continue into more extreme attitudes and you are above your DA minimum, you are legal.
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Old 25th Sep 2015, 09:39
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Was it North Weald QNH or Shoreham QFE set at the beginning of the display approx. 300' difference.
Is it? I read NW QNH at 1014 and Shoreham QNH 1013, with Shoreham on the sea QFE/QNH is comme ci comme sa?

Fortissimo - how are we judging 30deg pitch, both pilot and FDD on the ground? Accepting that in a Typhoon with a better than 1:1 thrust to weight you can just burn more fuel and make any error come good but when you don't have that luxury how does that methodology become repeatable and then throw in changes in temp, weight and ability to practice in all these different configurations.....
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Old 25th Sep 2015, 10:01
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AH may have already completed a loose article check during the inverted portion of his flight parallel to the coast prior to commencing his display.

Good to hear AH and others with injuries are recovering. I wish them all well soon.
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Old 25th Sep 2015, 11:28
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Pitts,

You keep banging on about height, weight and temperature. Let me put that issue to rest for you.

Shoreham Airfield is 7 feet above sea level. Given the QNH on the day, no problems with pressure altitude. Display altitude was not a performance factor in this accident.

The aircraft was filled to full deliberately because of the need to transit, hold, display, transit, recover. To get from North Weald to Shoreham, avoiding that big bit of airspace between them called London, would have meant something in the region of 150nms at reasonably low altitude. Including SUTTO, transit and hold he would have burnt at least 2500lbs, which you mean the external tanks were empty and internals no longer full (mental dead reckoning on my part and we don't know how long the hold was). It would have been normal to get airborne from the display location with full internals and display after a short hold with similar fuel to this event). This was not a heavyweight display; he was flying the aircraft at or near to the usual all up weight.

Aircraft fit: G-BXFI was always flown with the external tanks fitted; it is not common practice to remove and fit the tanks. Configuration was the same as flown for all AH's displays and practices. Configuration is not an issue.

Temperature: 28 degrees is not an unusually hot day for jet performance and only 3-5 degrees above the average for that area in the previous two months (depending on which Met Office data you use). Close enough to the conditions he was used to in recent displays/practices. Temperature on the day was not a significant factor. Combine that with what i said earlier about pressure altitude, you can deduce that density altitude was not a factor.

Within the bounds of the limited information available, it is reasonable to ASSUME that AH's decision to fill to full was sound and did not lead to abnormal auw at the time of the display. Aircraft fit was normal and was the same as he had flown previously during displays and practices. The met conditions on the day were not significantly different from those he had flown in recently.

Another drum that doesn't yield a meaningful tune.

Last edited by Courtney Mil; 25th Sep 2015 at 12:29.
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Old 25th Sep 2015, 12:01
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The other drum being repeatedly banged here is entry height for the manoeuvre in question. This has been addressed several times since it was first raised, most recently by Background Noise and Fortissimo.

Trim Stab, you are still making incorrect quotes about DA and these may be affecting your judgement on this matter. For example,

Originally Posted by trim stab
The AAIB preliminary report states that he commenced the display at 200' rather than 500' which was authorised
The Special Bulletin only stated the entry height, it did not go on to state anything about "rather than 500' which was authorised". It actually states

and then commenced a descending left turn to 200 ft amsl, approaching the display line at an angle of about 45o. The aircraft then pitched up into a manoeuvre with both a vertical component and roll to the left
I hope you now understand that the minimum entry height is not specified for that manoeuvre other than his overall display minimum.

As for being off the display line at entry, that is precisely the point of that manoeuvre. On the day it was 45 because of local restrictions.

In terms of energy, there is no problem with commencing a vertical manoeuvre from an altitude lower than the exit height provided the entry speed is appropriate. There is no evidence to suggest that AH flew that part of his display any differently on this occasion from previous displays or practices, with the possible exception of the amount of roll in the vertical to account for the different approach angle.

Those looking for fault or any deviation from authorisation and possible repercussions will now be able to look for something else to latch onto and beat to death. Your blood lust unsatisfied, you will doubtless be very disappointed.

The AAIB may well find that the entry height was a factor and may well recommend a change to the practice. Or they may not. We don't know and we shall have to wait. An interim report is a possibility in this case so it may not be that long.
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Old 25th Sep 2015, 12:12
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CM - The QNH point was a reply to a post by Above the clouds, which he has since deleted, and as you see from my reply I agree with your point.

Height, weight, temp, you've provided a view and one can respect that, i don't know how often, in what aircraft weight or config, or when he practiced, hence the question. You seem to have clarified this.

Those looking for fault or any deviation from authorisation and possible repercussions will now be able to look for something else to latch onto and beat to death. Your blood lust unsatisfied, you will doubtless be very disappointed.
I don't think that is what people are doing, they are just asking the question and actually given your final paragraph if the AAIB do recommend change would you then say that such a change is wrong and unnecessary?
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