Re-visiting the 1999 Hawk 200 Crash
Pitts
I didn't know the guy involved but from what I understand he was a pretty competent aviator (deliberate understatement). The bit that I'm struggling to comprehend though is that you seem to infer that your understanding of the humble barrel roll is greater than his.
I can assure you that us lowly FJ pilots are taught, and fully understand, the rigours of various aerobatic manoeuvres, the barrel roll being one of them. Throughout training I remember being reminded on numerous occasions how it was one of the most dangerous manoeuvres to fly.
No matter how awesome we may be (or think we are) though it can never stop us from making a mistake. Trying to claim that, had he possessed your zen like level of barrel roll acumen, he'd be alive today just seems a little obtuse to me.
Still, it's possible we are just failing to understand each other repeatedly so I'll give it a rest.
BV
I can assure you that us lowly FJ pilots are taught, and fully understand, the rigours of various aerobatic manoeuvres, the barrel roll being one of them. Throughout training I remember being reminded on numerous occasions how it was one of the most dangerous manoeuvres to fly.
No matter how awesome we may be (or think we are) though it can never stop us from making a mistake. Trying to claim that, had he possessed your zen like level of barrel roll acumen, he'd be alive today just seems a little obtuse to me.
Still, it's possible we are just failing to understand each other repeatedly so I'll give it a rest.
BV
Join Date: Aug 2007
Location: London, New York, Paris, Moscow.
Posts: 3,632
Likes: 0
Received 0 Likes
on
0 Posts
A very sad event indeed.
Ninja'd by Fox3...
All modern zero-zero seats are just rockets that accelerate the pilot/seat combination to a speed whereby the chute will successfully open if ejection is initiated on the ground; watch the testing videos and you'll see that man-seat separation starts with an upward vector ie at max speed after rocket firing ceases.
A small bank angle on the ground (eg due to a gear collapse) will reduce the upward throw but will probably not prevent the chute from deploying successfully. The problem with high rates of descent is that the time from handle pull to the chute opening is something like 1.5 to 2.0 seconds (generic) and then the chute has to slow the pilot down enough so that a soft ground 'impact' can be achieved. During that time you can fall whilst decelerating quite a long way. The conservative rule of thumb is to eject when your height is above 0.1 x rate of descent (in feet per minute). So at 300 KIAS in the vertical (approx 30000 ft per min) the min safe ejection height will be 3000 ft AGL. The aircraft document set will contain specific details about rates of descent v heights for a successful ejection.
Ninja'd by Fox3...
All modern zero-zero seats are just rockets that accelerate the pilot/seat combination to a speed whereby the chute will successfully open if ejection is initiated on the ground; watch the testing videos and you'll see that man-seat separation starts with an upward vector ie at max speed after rocket firing ceases.
A small bank angle on the ground (eg due to a gear collapse) will reduce the upward throw but will probably not prevent the chute from deploying successfully. The problem with high rates of descent is that the time from handle pull to the chute opening is something like 1.5 to 2.0 seconds (generic) and then the chute has to slow the pilot down enough so that a soft ground 'impact' can be achieved. During that time you can fall whilst decelerating quite a long way. The conservative rule of thumb is to eject when your height is above 0.1 x rate of descent (in feet per minute). So at 300 KIAS in the vertical (approx 30000 ft per min) the min safe ejection height will be 3000 ft AGL. The aircraft document set will contain specific details about rates of descent v heights for a successful ejection.
Pretty comprehensive instructional video...US biased but relevant even today I would say...
Bob - Can you tell me how flying a barrel roll in a fast jet differs from flying one in a Pitts Special, Extra 300, Chipmunk, Moth, Stampe, Yak, Sukhoi or Spitfire?
Fundementally at the top of the manoeuvre how does the picture look? Does it look differently?
Actually it's kind of relevant in 2014 because the current Typhoon demo has a barrel roll as figure 6, so what conversations are had to prevent accidents here? I might offer the suggestion that the pilot says if the picture doesn't look like this I'll roll wings level. What is your suggestion?
Leon I hear you re sink rates but the point I was making is it should never have got to that position and actually i dont think you suggest that it might.
Ultimately his DA was signed off and he would have no doubt made the sequence he flew.
Bob it's got nothing to do with me thinking I know better than him, I'm better than him, I'm being smug or anything of the sort. Things go wrong and when you look at the Hawk crash he was not fully inverted at the top. That's the beginning of the end.
Just like how some World class aerobatic pilots have sadly died by making poor weather decisions or RAF instructors getting killed spinning T67's. Don't shoot the messenger.
Fundementally at the top of the manoeuvre how does the picture look? Does it look differently?
Actually it's kind of relevant in 2014 because the current Typhoon demo has a barrel roll as figure 6, so what conversations are had to prevent accidents here? I might offer the suggestion that the pilot says if the picture doesn't look like this I'll roll wings level. What is your suggestion?
Leon I hear you re sink rates but the point I was making is it should never have got to that position and actually i dont think you suggest that it might.
Ultimately his DA was signed off and he would have no doubt made the sequence he flew.
Bob it's got nothing to do with me thinking I know better than him, I'm better than him, I'm being smug or anything of the sort. Things go wrong and when you look at the Hawk crash he was not fully inverted at the top. That's the beginning of the end.
Just like how some World class aerobatic pilots have sadly died by making poor weather decisions or RAF instructors getting killed spinning T67's. Don't shoot the messenger.
Re-visiting the 1999 Hawk 200 Crash
Pitts.
I tell you what. Once you have read the accident report, read the students study guides from EFT, BFJT and AFT (which will all, if memory serves me correctly, tell you that the wings should be level with the horizon at the inverted position) you should find that he did indeed know that he should have been fully inverted at the top.
As has been mentioned several times already, he made a mistake. For whatever reason he didn't realise in time. It would appear that commercial pressure played its part also.
Maybe you could submit an amendment that could be incorporated into all of our training manuals to ensure future generations have a better understanding of barrel rolls. Sarcastic I know but I'm just not getting your point to be honest. I think you've already had the answers you need so I'm not really sure why you're persisting.
Personally I never enjoyed aerobatics as a student. My aerobatic sequences always involved the bare minimum of manoeuvres and were unspectacular to say the least. Occasionally now I fly some if I have some spare fuel to burn. To be honest I don't fly barrel rolls very often since I don't like them. Slow loops, slow rolls and vertical aileron rolls are usually enough to sate my appetite.
BV
Broke my own resolve to give it a rest.
I tell you what. Once you have read the accident report, read the students study guides from EFT, BFJT and AFT (which will all, if memory serves me correctly, tell you that the wings should be level with the horizon at the inverted position) you should find that he did indeed know that he should have been fully inverted at the top.
As has been mentioned several times already, he made a mistake. For whatever reason he didn't realise in time. It would appear that commercial pressure played its part also.
Maybe you could submit an amendment that could be incorporated into all of our training manuals to ensure future generations have a better understanding of barrel rolls. Sarcastic I know but I'm just not getting your point to be honest. I think you've already had the answers you need so I'm not really sure why you're persisting.
Personally I never enjoyed aerobatics as a student. My aerobatic sequences always involved the bare minimum of manoeuvres and were unspectacular to say the least. Occasionally now I fly some if I have some spare fuel to burn. To be honest I don't fly barrel rolls very often since I don't like them. Slow loops, slow rolls and vertical aileron rolls are usually enough to sate my appetite.
BV
Broke my own resolve to give it a rest.
Join Date: Mar 2011
Location: Did I Tell You I Was A Harrier Pilot
Posts: 79
Likes: 0
Received 1 Like
on
1 Post
Pitts,
As you can see from this first fame of the video where the display manoeuvre is shown, only a person with super-human perception can determine the aircraft's angle of bank when it was at the top of the barrel roll (which you seem to think is important). Unless you have a different source of evidence, it appears that you are making your conclusions solely based only on your own preconceptions and limited experiences. Your technique of assessing whether the wings are level when inverted will ensure your display looks pretty but it is not a useful metric for ensuring you maintain safe recovery options when nose down in a fast jet. Frankly your 'expert' advice makes me question your expertise.
Angle of bank at the top of a barrel roll can be adjusted very quickly and, consequently, it is not a direct measure of whether or not any sort of rolling vertical manoeuvre will be successful - a quick adjustment of angle of bank can easily be made at any time later, so angle of bank when inverted is almost a meaningless check of whether the rest of the manoeuvre will be safely flown in a jet. You have to ensure that the nose is not lowered too much below the horizon for your available height, whether doing aerobatics or fighting in air combat.
In fast jets the critical factors for nose-low recoveries is the available g that the aircraft can achieve. Many aerobatic manoeuvres in jets like the hawk are flown near to (but not at) the CL Max, so there is some margin for increasing g - but not much (in the hawk at least). Having flown the Extra and Yak52 as well I can vouch that these slower types of aerobatic aircraft have the potential to increase their g quite substantially above that required for typical rolling manoeuvres, because of their light wing loading; thus the margins you might be used to are greater than those afforded to an average jet pilot who commits his nose below the horizon.
When I taught barrel rolls to students on the hawk I taught that it was important to always stay cognisant of the remaining height below the jet in combination with the jet's pitch attitude and bank angle / roll rate. There are rules of thumb available as a guide to how nose low you can commit yourself for any given height and these are padded for rolling vertical manoeuvres like barrel rolls. Similar techniques apply when flying a rolling scissors (I have also taught many of these...) - you always have to be aware of your pitch attitude as well as your angle of bank. The jet in the video attempts a 'floor save' by ceasing the display and rolling wings level, but the lack of height for pitch attitude was identified far too late, sadly.
The bottom line: when you say "when you look at the Hawk crash he was not fully inverted at the top. That's the beginning of the end" you're actually saying "I have no idea what I'm talking about".
As you can see from this first fame of the video where the display manoeuvre is shown, only a person with super-human perception can determine the aircraft's angle of bank when it was at the top of the barrel roll (which you seem to think is important). Unless you have a different source of evidence, it appears that you are making your conclusions solely based only on your own preconceptions and limited experiences. Your technique of assessing whether the wings are level when inverted will ensure your display looks pretty but it is not a useful metric for ensuring you maintain safe recovery options when nose down in a fast jet. Frankly your 'expert' advice makes me question your expertise.
Angle of bank at the top of a barrel roll can be adjusted very quickly and, consequently, it is not a direct measure of whether or not any sort of rolling vertical manoeuvre will be successful - a quick adjustment of angle of bank can easily be made at any time later, so angle of bank when inverted is almost a meaningless check of whether the rest of the manoeuvre will be safely flown in a jet. You have to ensure that the nose is not lowered too much below the horizon for your available height, whether doing aerobatics or fighting in air combat.
In fast jets the critical factors for nose-low recoveries is the available g that the aircraft can achieve. Many aerobatic manoeuvres in jets like the hawk are flown near to (but not at) the CL Max, so there is some margin for increasing g - but not much (in the hawk at least). Having flown the Extra and Yak52 as well I can vouch that these slower types of aerobatic aircraft have the potential to increase their g quite substantially above that required for typical rolling manoeuvres, because of their light wing loading; thus the margins you might be used to are greater than those afforded to an average jet pilot who commits his nose below the horizon.
When I taught barrel rolls to students on the hawk I taught that it was important to always stay cognisant of the remaining height below the jet in combination with the jet's pitch attitude and bank angle / roll rate. There are rules of thumb available as a guide to how nose low you can commit yourself for any given height and these are padded for rolling vertical manoeuvres like barrel rolls. Similar techniques apply when flying a rolling scissors (I have also taught many of these...) - you always have to be aware of your pitch attitude as well as your angle of bank. The jet in the video attempts a 'floor save' by ceasing the display and rolling wings level, but the lack of height for pitch attitude was identified far too late, sadly.
The bottom line: when you say "when you look at the Hawk crash he was not fully inverted at the top. That's the beginning of the end" you're actually saying "I have no idea what I'm talking about".
Last edited by DITYIWAHP; 6th Sep 2014 at 16:35.
The following users liked this post:
Do a Hover - it avoids G
Join Date: Oct 1999
Location: Chichester West Sussex UK
Age: 91
Posts: 2,206
Likes: 0
Received 0 Likes
on
0 Posts
Chaps
I look at these two Hawk accidents from a slightly different perspective to some posters.
It seems to me that the common factor with both was that the pilot pulled while at the wrong bank angle.
At the point in the first accident routine where it went wrong the pilot rolled to 180 deg bank and pulled hard where normally he only rolled to about 110-120 deg bank before pulling hard round in a descending turn. Why he did this concerned me because apart from my test flying and display background I was the manager of Dunsfold at the time of the accident. Remember it was an instrumented aircraft and the records survived so we knew exactly what happened.
I also witnessed the event and saw the aircraft roll a little one way and then a little the other (not wing rock) while it was going close to vertically down. I speculate that at that point the pilot realised all he could see was ground and not the horizon and was trying to find the nearest horizon.
I had seen the display countless times before and it never gave me the slightest concern.
All of which leaves me wondering why the pilot did not realise he had the wrong bank angle at the moment of starting the pull. As we know one’s eyes are normally the most reliable of our sensors when it comes to a violent manoeuvre. However they can give you a false picture under some conditions, in particular if a bout of nystagmus is stimulated by the manoeuvre. I have a number of possibilities in my mind that could account for the first accident pilot’s disorientation but they are pure guess work so I am not going into them here.
I have been watching and later participating in airshows since 1950. After I saw the 10th aircraft fly into the ground I stopped counting. Of those first 10 only one had a technical issue. On three of the occasions I realised the pilot had lost it and told those who were with me that he was going to crash. On another in South America it was so obvious what was going to happen that I told those I was with that I was not going to watch and would go back into the chalet until it was all over.
I look at these two Hawk accidents from a slightly different perspective to some posters.
It seems to me that the common factor with both was that the pilot pulled while at the wrong bank angle.
At the point in the first accident routine where it went wrong the pilot rolled to 180 deg bank and pulled hard where normally he only rolled to about 110-120 deg bank before pulling hard round in a descending turn. Why he did this concerned me because apart from my test flying and display background I was the manager of Dunsfold at the time of the accident. Remember it was an instrumented aircraft and the records survived so we knew exactly what happened.
I also witnessed the event and saw the aircraft roll a little one way and then a little the other (not wing rock) while it was going close to vertically down. I speculate that at that point the pilot realised all he could see was ground and not the horizon and was trying to find the nearest horizon.
I had seen the display countless times before and it never gave me the slightest concern.
All of which leaves me wondering why the pilot did not realise he had the wrong bank angle at the moment of starting the pull. As we know one’s eyes are normally the most reliable of our sensors when it comes to a violent manoeuvre. However they can give you a false picture under some conditions, in particular if a bout of nystagmus is stimulated by the manoeuvre. I have a number of possibilities in my mind that could account for the first accident pilot’s disorientation but they are pure guess work so I am not going into them here.
I have been watching and later participating in airshows since 1950. After I saw the 10th aircraft fly into the ground I stopped counting. Of those first 10 only one had a technical issue. On three of the occasions I realised the pilot had lost it and told those who were with me that he was going to crash. On another in South America it was so obvious what was going to happen that I told those I was with that I was not going to watch and would go back into the chalet until it was all over.
Pitts,
As the previous two posters have stated, you may have rather over-simplified the "picture at the top" argument. Being purely inverted at the top is not the important criteria, it is the relationship between pitch and roll at that stage that is important. Too much pitch with too little roll will level you in big trouble, correctly inverted or not!
As the previous two posters have stated, you may have rather over-simplified the "picture at the top" argument. Being purely inverted at the top is not the important criteria, it is the relationship between pitch and roll at that stage that is important. Too much pitch with too little roll will level you in big trouble, correctly inverted or not!
The following users liked this post:
Flap62 wrote:
Well, personally I'd say too little pitch attitude (above the horizon) at the inverted point is the real killer.... Because what happens next, unless it's a 'spot roll out' recovery manoeuvre is a nose-buried descent, with a dangerously steep pitch attitude and high descent rate once wings level is achieved.
Unless there's a lot more blue than green at the half-way stage, throw it away.
Was sun dazzle ever considered in this Hawk accident? Pull up, pitch and roll, roll and pitch and...!!!!, where's the horizon gone
Too much pitch with too little roll will level you in big trouble, correctly inverted or not!
Unless there's a lot more blue than green at the half-way stage, throw it away.
Was sun dazzle ever considered in this Hawk accident? Pull up, pitch and roll, roll and pitch and...!!!!, where's the horizon gone
Each to their own Beag
I personally tend to say to myself "pitch" til heals go through horizon then introduce increasing roll, backing off on the roll as heals go through horizon on way down with increasing pitch. That said, my aeros are shocking!
It's like most of a good aeros sequence, balanced co-ordinate inputs.
I personally tend to say to myself "pitch" til heals go through horizon then introduce increasing roll, backing off on the roll as heals go through horizon on way down with increasing pitch. That said, my aeros are shocking!
It's like most of a good aeros sequence, balanced co-ordinate inputs.
Join Date: May 2007
Location: upstairs
Posts: 208
Likes: 0
Received 0 Likes
on
0 Posts
...never seen the accident report.
The BOI was convened as a D Flying 'PE fleet' investigation (a/c was operated under Def Stan 05-122 'COMA' arrangements) but the report may not have been published widely. ISTR (vaguely, it was a long time ago) that the view was that the barrel roll became steeper than intended and in effect became a loop from which there was insufficient height to recover.
My apologies Bob re: T67's I was thinking of this and you're right thankfully no deaths. However I guess the point was that its an odd thing to happen given the experience and the task at hand. We digress.
http://www.aaib.gov.uk/cms_resources...UH%2010-95.pdf
Flap and "used to fly harriers" - the cross referencing of pitch to roll was of course taken as given because how else are we barrel rolling..!??
However re my over simplification of the picture at the top, lets not take my word for it... Here are the words of someone to please everyone... RAF and aerobatic champion Neil Williams....
Funny old thing that.
http://www.aaib.gov.uk/cms_resources...UH%2010-95.pdf
Flap and "used to fly harriers" - the cross referencing of pitch to roll was of course taken as given because how else are we barrel rolling..!??
However re my over simplification of the picture at the top, lets not take my word for it... Here are the words of someone to please everyone... RAF and aerobatic champion Neil Williams....
a very common fault with the barrel roll is to roll too slowly to start with so that the nose comes down through the horizon before the wings are level inverted. The result of this is a high speed spiral dive with considerable height loss.
Below the Glidepath - not correcting
Regarding the original question from the OP, the "chain of events" started well before the manoeuvre. The discussion here dissects the components of a correctly executed barrel roll, but a pilot of his experience would have been well aware of those. Display flying is littered with examples of errors of judgement driven by the very nature of public performance. The temptation to either make the display more "sporting" than the original DA, or to ignore airborne cues that the safe or authorized operating envelope is being exceeded is always there. That is why the practice and review are critical. This was a commercial display as part of a sales drive for the aircraft. Whatever the airmanship errors were in the cockpit, the environment for increased risk and display pressures were already present. No one will ever know if these were a significant factor in the accident, but it's probably safe to assume this accident was not caused by the pilot not knowing how to perform a barrel roll.
Although Graham's accident was now many years ago I studied the report thoroughly at the time (and had access to the ADR traces) because he and I had been at UAS together and later were together on Experimental Flying Squadron at Farnborough. What I write below is from memory but it has always stuck with me.
Let's first consider some basics for a barrel roll. It is a manoeuvre that involves a simultaneous roll rate (generally quite low and significantly less than the maximumm achievable, espcially in an aircraft like a Hawk) and nose up pitch rate (ie load factor will be greater than +1g throughout). To fly one neatly in a display you try to to maintain a constant roll rate from commencing the roll until back at wings level erect. Therefore, any adjustments required for positioning the manoeuvre are achieved largely by adjusting the pitch rate/g although roll rate can be varied, especially for safety. The concept of a gate height as is used foor looping manoeuvres is not valid for a barrel roll because the minimum top height from which the manoeuvre can be safely completed will be a function of the roll rate and pitch rate during the second half of the manoeuvre. Also, if you are attempting to fly a barrel roll in a display positioned symmetrically about crowd centre the maximum nose low attitude on the way down will be dictated by the maximum pitch attitude on the way up.
In this thread so far there has, surprisingly, been no discussion regarding the orientation of the manoeuvre with respect to the crowd line (although this is not shown on the embedded video clip). Graham entered the manoeuvre from crowd left angled towards the crowd line at approximately 45 degrees and pitched up wings level at around +6g to approximately 60 degrees (numbers all from memory). He then commenced rolling left which turned the aircraft away from the crowd and he maintained at least 4g throughout. This generated a good angle away from the crowd but the roll rate that he used combined with such a high pitch rate resulted in a nose down attitude/altitude combination during the third quarter of the roll which was irrecoverable. I recall that the g values on the final manoeuvre were even higher than those on the practise that he had flown. However, the height achieved at the top would have been affected significantly by the nose up pitch attitude at which he started to roll and I cannot recall the difference between the practise and the accident sorties.
This set-up is inherently difficult to fly and requires large variations in pitch rate to achieve the required positioing. When you start to roll you need a large pitch rate to achieve the change in flightpath from towards the crowd to away from it. However, once the bank angle is about 120 degrees you need to slacken the pull or you become too nose low at the wings level inverted. During the second half of the roll you have to adjust pitch rate/g and possibly roll rate to have a final flightpath, which will always be angled towards the crowd line, that is clear of the end of the actual crowd area. Therefore, in the second half of the roll the pilot is concentrating on making control inputs to achieve the exit line (and thus prevent a crowd infringement) and could lose awareness of altitude and attitude. Overall, it can be quite an asymmetric manoeuvre when viewed from the cockpit and from the end of the display line although it looks OK from crowd centre.
This was Graham's first public display. He had worked the display up in an approved and supervised manner. He was still learning the art of display flying and had included an extremely tight barrel roll from a difficult set-up. I discussed informally my views on how this accident could have been avoided with the pilot member of the Board of Inquiry (and I did disagreed with at least one of their recommendations) but I will not expand on those here.
A barrel roll is a difficult manoeuvre to position well in a display. There are ways to do so safely and there are orientations, such as the one used by Graham, that involve a higher risk of CFIT. I am not being critical of the decision for him to fly this because I used the same during my first display season which was in a jet much heavier and less manoeuvrable than the Hawk.
Finally, reference has been made to NMacC's acccident. This was during a rollback which, although a simultaneous rolling and pitching manoeuvre, is not a barrel roll per se. It has a much smaller radius and faster roll rate and results in a relatively small lateral displacement. During this manoeuvre NMacC's aircraft departed from controlled flight which resulted in ground impact. Another tragic accident but one in which the considerations were totally different to the above discussion on barrel rolls.
Rgds
L
Let's first consider some basics for a barrel roll. It is a manoeuvre that involves a simultaneous roll rate (generally quite low and significantly less than the maximumm achievable, espcially in an aircraft like a Hawk) and nose up pitch rate (ie load factor will be greater than +1g throughout). To fly one neatly in a display you try to to maintain a constant roll rate from commencing the roll until back at wings level erect. Therefore, any adjustments required for positioning the manoeuvre are achieved largely by adjusting the pitch rate/g although roll rate can be varied, especially for safety. The concept of a gate height as is used foor looping manoeuvres is not valid for a barrel roll because the minimum top height from which the manoeuvre can be safely completed will be a function of the roll rate and pitch rate during the second half of the manoeuvre. Also, if you are attempting to fly a barrel roll in a display positioned symmetrically about crowd centre the maximum nose low attitude on the way down will be dictated by the maximum pitch attitude on the way up.
In this thread so far there has, surprisingly, been no discussion regarding the orientation of the manoeuvre with respect to the crowd line (although this is not shown on the embedded video clip). Graham entered the manoeuvre from crowd left angled towards the crowd line at approximately 45 degrees and pitched up wings level at around +6g to approximately 60 degrees (numbers all from memory). He then commenced rolling left which turned the aircraft away from the crowd and he maintained at least 4g throughout. This generated a good angle away from the crowd but the roll rate that he used combined with such a high pitch rate resulted in a nose down attitude/altitude combination during the third quarter of the roll which was irrecoverable. I recall that the g values on the final manoeuvre were even higher than those on the practise that he had flown. However, the height achieved at the top would have been affected significantly by the nose up pitch attitude at which he started to roll and I cannot recall the difference between the practise and the accident sorties.
This set-up is inherently difficult to fly and requires large variations in pitch rate to achieve the required positioing. When you start to roll you need a large pitch rate to achieve the change in flightpath from towards the crowd to away from it. However, once the bank angle is about 120 degrees you need to slacken the pull or you become too nose low at the wings level inverted. During the second half of the roll you have to adjust pitch rate/g and possibly roll rate to have a final flightpath, which will always be angled towards the crowd line, that is clear of the end of the actual crowd area. Therefore, in the second half of the roll the pilot is concentrating on making control inputs to achieve the exit line (and thus prevent a crowd infringement) and could lose awareness of altitude and attitude. Overall, it can be quite an asymmetric manoeuvre when viewed from the cockpit and from the end of the display line although it looks OK from crowd centre.
This was Graham's first public display. He had worked the display up in an approved and supervised manner. He was still learning the art of display flying and had included an extremely tight barrel roll from a difficult set-up. I discussed informally my views on how this accident could have been avoided with the pilot member of the Board of Inquiry (and I did disagreed with at least one of their recommendations) but I will not expand on those here.
A barrel roll is a difficult manoeuvre to position well in a display. There are ways to do so safely and there are orientations, such as the one used by Graham, that involve a higher risk of CFIT. I am not being critical of the decision for him to fly this because I used the same during my first display season which was in a jet much heavier and less manoeuvrable than the Hawk.
Finally, reference has been made to NMacC's acccident. This was during a rollback which, although a simultaneous rolling and pitching manoeuvre, is not a barrel roll per se. It has a much smaller radius and faster roll rate and results in a relatively small lateral displacement. During this manoeuvre NMacC's aircraft departed from controlled flight which resulted in ground impact. Another tragic accident but one in which the considerations were totally different to the above discussion on barrel rolls.
Rgds
L
