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-   -   Hawker Hunter down at Shoreham (https://www.pprune.org/accidents-close-calls/566536-hawker-hunter-down-shoreham.html)

dsc810 5th Sep 2015 13:36

It could also be that the application of flaps with the additional drag component that they provide meant that the Avon engine can be run in a more favourable part of its operating region: particularly one where the variable guide vanes of the engine were not constantly moving back/fro.

This would be especially relevant during formation aerobatics where small throttle movements coupled with unwanted guide vane movement would give confusing thrust variations.

BEagle 5th Sep 2015 14:07

Ranger One wrote:

Derfred, Hunter isn't supersonic, tops out at ~0.95M IIRC.
Not so. The Hunter was supersonic in a dive; even with less thrust as compared with the F6, the T7 exceeded M1.0 quite easily thanks to its area ruled fuselage.

Entirely irrelevant for this accident though. But yes, use of 23° flap is quite normal for Hunter aerobatics.

Machinbird 5th Sep 2015 18:52

Humans in a jet environment.
 

Originally Posted by 118.9
It leaves me wondering if there was a brief incapacitation of the pilot at the apex?

If you are going to have a g induced incapacitation, it would have occurred approaching the 90 degree nose up point. After that, the g level would be too low until the g begins to build on the pull out.

From personal experience, if you lose your vision at high g, it might take up to 15 seconds at low g to regain the center of your visual field.

At high g, your visual field collapses to a narrow tunnel and if you maintain the g, whatever is visible in the tunnel fades away. At slightly higher g, your brain will fade away.

Due to internal pressure in the eye, it takes slightly more blood pressure to supply the eye than the brain.

The art of maintaining blood pressure in the head is learned during exposure to high g. Tensing muscles in the legs and abdomen, and proper use of the diaphragm is critical in maintaining performance at high g.

If a person were to begin a maneuver with lower than normal blood pressure or while experiencing some other physiological event (like the aftermath of a 2 doughnut breakfast) then their performance at g may be substandard.

Aerobatics in jets can generate very high g loads and the g can be prolonged much more so than in propeller driven aircraft.

Once the g gets up to 4 g, the possibility of adverse physiological events becomes very significant. To repeat a question I asked earlier, was a g suit being used?:confused:

Chronus 5th Sep 2015 19:22

Pilot experience on type
 
The AAIB report states:

"From the pilot’s electronic logbook, it was established that the pilot had flown a total of 40.25 hours in the Hunter since 26 May 2011, of which 9.7 hours had been flown in the last 90 days and 2.1 hours in the last 28 days."

This would indicate that the pilot had flown an average of 10hrs during the previous three air display seasons and 11.1hrs during this year. These times, which are brake to brake, would include non- display times whilst travelling to/from show venues, which when factored in would significantly reduce the time that was actually remained for practice and display.

When compared with the time spent on practice by teams such as the red arrows, it must surely bring into question whether pilot experience for fast jet displays is a matter that may need further consideration.

Tourist 5th Sep 2015 19:39

To be fair Chronus, the Red Arrows are doing something orders of magnitude more demanding in terms of skill.


The Shuttleworth Collection work in minutes airborne per season.

Chronus 5th Sep 2015 20:09

Yes Tourist, the Red Arrows do set the standard by which skill is measured. However what is skill. My understanding of it is that it involves a gradual development process and is acquired with continuous practice, there can be no other way of becoming skilful. It takes time to learn and develop skills. We all know and understand that only a handful such as the Red Arrows have attained the top skills and to maintain it they practice daily. However for the lesser mortals what would be the a safe measure/standard of skill.
Perhaps there being no room for error and compromise in safety, could it be be possible that the matter of pilot experience on type may become an issue to consider for future public air displays, especially when it comes to vintage jets, with their time in the air so carefully preserved, to take to the skies on the rare few days of the year.

skyrangerpro 5th Sep 2015 22:59

"It would appear that this is the key comment from the initial report. If I understand correctly, the loop was entered at around 200ft. I would ask those who know if that is within acceptable licensed parameters."

That's not really the point is it, suppose the loop was entered into at 500ft instead, do you really think it is prudent to exit the loop at 300ft above the A27?

Wrong place not just wrong height.

PrivtPilotRadarTech 5th Sep 2015 23:04

Well said, Chronus. Practice makes perfect, but the cost of flying hours and maintenance is a problem in these historic aircraft. I love seeing (and hearing!) War Birds, but every one that is destroyed robs future generations. That responsibility should be factored into airshow displays. If you're flying a Pitts Special, have at it, but if it's an irreplaceable Hunter, Hurricane, or A-26...

Loose rivets 6th Sep 2015 02:00

apropos the rescue. From the report.


During the initial part of the impact sequence the jettisonable aircraft canopy was released, landing in a tree close to the main aircraft wreckage. During the latter part of the impact sequence, both the pilot and his seat were thrown clear from the cockpit.

deanm 6th Sep 2015 05:04

What distinguishes this tragic Shoreham event from this one (public event, fast, high-powered metal, innocent bystanders) :

Cookies must be enabled. | The Australian

These types of disasters have been happening ever since...we invented internal combustion engines.

I believe spectators have even even been killed or seriously injured by wayward horses at equestrian events.

What should we all do - stay home wrapped in protective cotton wool?

Dean

Dr Jekyll 6th Sep 2015 05:25


That's not really the point is it, suppose the loop was entered into at 500ft instead, do you really think it is prudent to exit the loop at 300ft above the A27?
I think it's more complicated than that though. There is more than a suggestion that once the aircraft was obviously too low an attempt to pull up hard caused a stall and a loss of more height.

It could be that he was originally flying so as to exit the loop at the same height he entered it, but lost the extra few hundred feet at this point.

Tourist 6th Sep 2015 05:55


Originally Posted by PrivtPilotRadarTech (Post 9106993)
I love seeing (and hearing!) War Birds, but every one that is destroyed robs future generations. That responsibility should be factored into airshow displays. If you're flying a Pitts Special, have at it, but if it's an irreplaceable Hunter, Hurricane, or A-26...

I totally disagree

An iconic aircraft in a museum is like a priceless painting kept in the dark.


Fly it like it was designed to be flown so it can be enjoyed.

Better to burn out than to fade away.

Arfur Dent 6th Sep 2015 07:48

CHRONUS HAS IT.
As I said many posts ago - here we have a good pilot who USED to be a professional FJ man as was I. He has done about 30 minutes of actual air show flying in the last 12 months and only has 40 hours total in the Hunter.
Operational Hunter display pilots back in the day would do that in a month!
Not wishing to prejudge but the aircraft that stalled into the road was, by all accounts, serviceable.
Why start the display from such a low height? Half the crowd can't even see him at 200 FT - apart from any other inherent danger of starting a looping manoeuvre so low!
The days of the Red Gnats zooming over the countryside at 10ft after a bomb burst are, sadly, gone but then again, they practice day in day out for months on end before we see them.
It's all down to money of course. What we need are some professional air display pilots who do nothing else but fly historic fast jets for a living. £100,000 a year and enough practice to be up to the job 100% of the time.
Instead we have 55-70 year olds who were pretty good in their day but simply don't do enough of this type of flying.

Dr Jekyll 6th Sep 2015 07:55

I can understand how a mishandling of the controls can be put down to inexperience or lack of currency. But supposing the initial problem was indeed entering the manoeuvre too low, would that really be a currency issue?

After all the Thunderbirds pilot who crashed an F16 after getting his entry height badly wrong was not only a full time F16 pilot but a full time display pilot. In fact there was a suggestion that the regular recent practicing he had done at an airfield rather closer to sea level was a factor in the accident.

Tandemrotor 6th Sep 2015 08:59

Don't get carried away.

The AAIB are almost certainly the best in the World at what they do. Their integrity is utterly beyond reproach. Their aim is never 'blame'! They simply seek to understand why and how accidents happen, so that we are all safer in what we do.

This interim report is merely a statement of very limited facts, as they are currently understood, and we have to read the report extremely carefully, because every single word will be well chosen, and accurate.

They have said the a/c 'appeared' to be responding normally to control inputs. They have not (yet) said the a/c was fully serviceable. They have not (yet) commented on the physical well being of the pilot, during this manoeuvre. etc.

As we have heard earlier here. Just because the a/c's second pass was (estimated?) at 200' that does not simply mean the aerobatic manoeuvre necessarily commenced from this (approximate) height. One would need to fully understand the nature of aerobatic routines to make that call.

This information is exactly what it says 'on the tin'; a preliminary report. There is still a very long way to go. Much not yet known. Much to be double and triple checked. We may learn more by about this time next year.

Until then, there will still be those happy to speculate on the basis of one or two snippets of information.

As has occurred in the past, they may be proved wrong!

notapilotbut 6th Sep 2015 09:18

Realising exit height too low?
 
I don't think anyone has yet mentioned how well the pilot knew the terrain before flying it? The A27 road bridge runs across the Adur river around 70 feet above it at the point of the crash, the hills of the downs at around 280 feet are to the east and the west with the pinnacle of the Lancing College church adding to the height, 3 bridges cross the river including that of the A27. Downdrafts or curl over from the hills would need to be considered, lack of buoyancy from air at up to 29c on that day, ese breeze at about 12mph. It's a complex picture without trying to fly upside down and in the seconds he had to consider how to recover, there simply wasn't enough time having initiated the manouevre very low. He may have been at 200 feet asl, but that leaves him only around 130 feet at a guess between him and the road at the point at which he initiated the climb.

A and C 6th Sep 2015 10:06

Wise words from Tandemrotor that all on this forum would best consider before committing to post.

It is rather a pity that such words are not heeded by members of the press who deliberately misuse such reports to embellish their so called news story's. The misleading rubbish I have seen printed must be deeply disturbing to those closely involved resulting in much distress at a time when they least need to be burdened by such publicity.

ExSimGuy 6th Sep 2015 10:07

Putting things into perspective . . . .
 
The news is just reporting an accident involving a car rally in Spain
A Coruna rally: Spain crash leaves six dead - BBC News

"Six people, including a pregnant woman, have been killed after a car veered off the road during a car rally in north-western Spain.Police said that 16 people had been injured, some critically, after the accident at the A Coruna car rally.
Television footage showed the car crashing off the road into spectators in a cloud of dust. Police said that the car had been going too fast."

Admittedly the victims of this event may be "not innocent by-standers, but those who voluntarily came to watch", however there would appear to be a parallel here from another type o spectator sport. It remains to be seen if laws will be changed for motor-sport events as a result - "***** happens".

(and as has been posted several times before, civil airliners have crashed into towns killing many on the ground, without calls for a ban on civil air traffic)

118.9 6th Sep 2015 10:17


Originally Posted by Arfur Dent
What we need are some professional air display pilots who do nothing else but fly historic fast jets for a living. £100,000 a year and enough practice to be up to the job 100% of the time.

Dream on Dent. Who's going to pay for the historical jets, the fuel, the maintenance, the salaries for professional pilots and engineers, and ...
The net result would be that classic jets would just fade away, only to be seen in museums or at scrap merchants.
The real issues are about competency and knowing your own limits and those of your aircraft. Why shouldn't a 60 year-old take to the sky and fly a safe but less spectacular display than he did in his heyday? In any event the pilot, whoever he or she is, must satisfy the conditions of the display authorisation. No doubt the show pilots doing aerobatic manaoeuvres will have preformed their exact routine in front of the air show safety officer, before the show, to receive a sign-off (validation).

A and C 6th Sep 2015 10:37

Informed risk
 
If one attends an event that has an eliment of risk it should be obvious enough to all that you accept these risks as part of the activity.

It is also a responsabilty of the organization of the event to minimize the risk to those attending, if you go to any Motorsport event held on closed roads ( the Isle of Man & Northern Ireland for example ) you will find some areas such as the outsides of corners are prohibited to spectators. This is a responsable way to mitigate the risks.

The air show organization in the UK is also run along these lines with strict rules about flying over and towards the spectators. Those who choose not to pay the entry fee and view the airshow from a protected area must except that they do not enjoy the same level of safety as those do.

Had there not been spectators on the road outside the airfield the casualty numbers would have been much lower and confined to those who happened to be by unfortunate chance be on the road at the time and did not deliberately choose to take the informed risk of viewing an airshow from a place with less protection.

I am sure that the review of airshow safety that will follow this event will look at risks to those outside the airfield area who have nothing to do with the event but it is difficult to protect those who choose to stand outside the protected areas but very near to the display while viewing the airshow.


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