Seeing what you expect to see
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Seeing what you expect to see
Last week I fell victim to what I believe is a classic case of 'seeing what you expect to see'
I was flying an Islander (Twin piston, high wing aircraft) My forth flight of the day. At the time of flight I only had 28 hours on type. (I should perhaps point out that this was an aerial work flight, not public transport.)
For those who are not familular with the BN2a Islander, the aircraft is a versitial, short take off, tough, utility aircraft. The builders did not skimp on rivets for instance! The 'flight deck' if I can call it that, is mainly in the same vein. Very workman like. The one let down is the flap selector. A small switch in a recess under the throttle quandrant. The flap indicator is on the eye brow panel above the P1s head. The switch is spring loaded. Hit it once, the flaps travel to stage one, again to get to stage two. It is very common to select flaps, they appear to be moving, but they dont. Double checking is vital especially for take off and already a couple of my approachs have ended up high (not a problem in this aircraft) due to delays in the flaps coming down.
On this flight I completed my take off checks, and as I taxied on to the runway I looked back over my left sholder to visually assertain the flaps were set to take off. I swear I saw the flaps in the correct position!
It wasn't until rotate at 60kts that I realised the pull was much heavier and the aircraft did not leave the ground. I glanced up and saw the flap indicator at zero! We lifted off at around 78 knots (Normal lift off is 65) The trees at the end were very close. but we did climb out okay.
Obviously by the time I realised I didnt have flaps I was commited to the take off.
This aircraft is such a good performer that it wasn't a problem but I estimate I used 50% more TODA to get to 50'! It could easily have ended in tears.
I hope I have learned my lesson on this aircraft. I knew the flap selector was a potential problem. The point is, looking back I still think I saw take off flaps! I must have had that picture in my head from all the previous flights and saw it even when it wasn't there.
Hopefully others can learn from this as well (Has anyone else had this, ie 'seen' three greens on finals?)
I was flying an Islander (Twin piston, high wing aircraft) My forth flight of the day. At the time of flight I only had 28 hours on type. (I should perhaps point out that this was an aerial work flight, not public transport.)
For those who are not familular with the BN2a Islander, the aircraft is a versitial, short take off, tough, utility aircraft. The builders did not skimp on rivets for instance! The 'flight deck' if I can call it that, is mainly in the same vein. Very workman like. The one let down is the flap selector. A small switch in a recess under the throttle quandrant. The flap indicator is on the eye brow panel above the P1s head. The switch is spring loaded. Hit it once, the flaps travel to stage one, again to get to stage two. It is very common to select flaps, they appear to be moving, but they dont. Double checking is vital especially for take off and already a couple of my approachs have ended up high (not a problem in this aircraft) due to delays in the flaps coming down.
On this flight I completed my take off checks, and as I taxied on to the runway I looked back over my left sholder to visually assertain the flaps were set to take off. I swear I saw the flaps in the correct position!
It wasn't until rotate at 60kts that I realised the pull was much heavier and the aircraft did not leave the ground. I glanced up and saw the flap indicator at zero! We lifted off at around 78 knots (Normal lift off is 65) The trees at the end were very close. but we did climb out okay.
Obviously by the time I realised I didnt have flaps I was commited to the take off.
This aircraft is such a good performer that it wasn't a problem but I estimate I used 50% more TODA to get to 50'! It could easily have ended in tears.
I hope I have learned my lesson on this aircraft. I knew the flap selector was a potential problem. The point is, looking back I still think I saw take off flaps! I must have had that picture in my head from all the previous flights and saw it even when it wasn't there.
Hopefully others can learn from this as well (Has anyone else had this, ie 'seen' three greens on finals?)
Last edited by Jump Complete; 13th May 2005 at 16:31.
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Excellent post - thanks for putting it here. I have also been caught out by the "agricultural" nature of the Islander's flaps system, when they wouldn't retract after takeoff.
One or two points occur to me on your incident:-
You are fortunate in having caught a potential incident, compounded possibly by your own (natural) error when the results were not very significant. I guarantee that BN2 flaps will not catch you out again!
One or two points occur to me on your incident:-
- The flap indicator, not just the flap selector switch, is known on quite a few BN2's to be "iffy" at times. Visual checks not a bad idea at all. I always used to press (or lift) the selector, hold it, and look at the indicator to check if it was actually moving, then release the selector. A few seconds later, a visual check of both the indicator and of the surfaces themselves, i.e. doublechecking the indication.
- On a visual check, if you have any aileron input (e.g. to compensate for a X-wind) it is easy to see the difference of angle between the flap and the aileron as flaps DOWN instead of aileron UP.
- You say you estimate you used 50% more ground roll. Are you sure you were committed to takeoff and could not have aborted?
You are fortunate in having caught a potential incident, compounded possibly by your own (natural) error when the results were not very significant. I guarantee that BN2 flaps will not catch you out again!
Thread Starter
Thank you-to answer your questions:
1. Whilst I was (obviously!) aware of the weakness of the flap selector I was not specifically aware of a problem with the flap indicator. Naturally I never rely on any gauge singly anyway and in this incident (as I was advised to do during the check out because of the problem) I did do a visual check of the flaps and thought I saw the correct picture. From now on I will do as you advise and cross check indicator with flap position.
2.It is possible the ailerons confused the picture but on the day the cross wind was from the right. I do not know if I had already applied the into wind aileron but logically the left aileron would have been down not up in this case.
3. The distances are a guess. ( I ment distance to 50') A normal take off at the wieght I was at would have put me at approxiately 100' by the end of the runway at which point I would begin the 20 degree right turn for noise abatement. I was only at 20' at this point. I was simply concontrating on establishing a safe climb at this time. With immediate hard braking from the time I was aware of the problem I probably could have stopped but my instinct was that I would get airborne and this felt like the best bet.
I think you are right about not getting caught again, I hope! Not just with this problem but 'singing the song' as you say. Parachute operations particually it is a real risk and one I work very hard to avoid. However, on lift 8 or 10 on a long hot day, it is easy to not apply the same diligence to take off checks as on lift 1!
1. Whilst I was (obviously!) aware of the weakness of the flap selector I was not specifically aware of a problem with the flap indicator. Naturally I never rely on any gauge singly anyway and in this incident (as I was advised to do during the check out because of the problem) I did do a visual check of the flaps and thought I saw the correct picture. From now on I will do as you advise and cross check indicator with flap position.
2.It is possible the ailerons confused the picture but on the day the cross wind was from the right. I do not know if I had already applied the into wind aileron but logically the left aileron would have been down not up in this case.
3. The distances are a guess. ( I ment distance to 50') A normal take off at the wieght I was at would have put me at approxiately 100' by the end of the runway at which point I would begin the 20 degree right turn for noise abatement. I was only at 20' at this point. I was simply concontrating on establishing a safe climb at this time. With immediate hard braking from the time I was aware of the problem I probably could have stopped but my instinct was that I would get airborne and this felt like the best bet.
I think you are right about not getting caught again, I hope! Not just with this problem but 'singing the song' as you say. Parachute operations particually it is a real risk and one I work very hard to avoid. However, on lift 8 or 10 on a long hot day, it is easy to not apply the same diligence to take off checks as on lift 1!
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Hi JC,
Interesting post. What I like about the aviation industry (or what I see of it anyway), is that it appears that people tell others of their mistakes / problems so others can learn from them. In many other professions they're quickly hidden under the carpet.
I often see Army Islanders in Gloucestershire EGBJ and when you mentioned the 20degree noise abaitment - I wondered if its you who's flying them?
G-ANDY
Interesting post. What I like about the aviation industry (or what I see of it anyway), is that it appears that people tell others of their mistakes / problems so others can learn from them. In many other professions they're quickly hidden under the carpet.
I often see Army Islanders in Gloucestershire EGBJ and when you mentioned the 20degree noise abaitment - I wondered if its you who's flying them?
G-ANDY
Many years ago, at the end of a two hour final handling check, I "saw" and called "three greens" on finals at RAF St Mawgan. Only the runway caravan operator prevented what would have been a very embarressing wheels up landing!
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While we're here, it might be worth mentioning that, if you ever get airborne flapless by mistake and suffer an engine failure, remember to climb at Vyse not V2, or you may well stall.
The J31 (for example), like many other small aircraft, does not have a take-off configuration warning (other than the pilots!) and I have known of flapless take-offs taking place (to put it tactfully!). On a long runway it's not a problem with that particular aircraft, unless you lose an engine subsequently.
The J31 (for example), like many other small aircraft, does not have a take-off configuration warning (other than the pilots!) and I have known of flapless take-offs taking place (to put it tactfully!). On a long runway it's not a problem with that particular aircraft, unless you lose an engine subsequently.
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Jump Complete
Good post, you will not make that mistake again well done. Quite a few years ago i was coming back on a check ride (military), the sortie had been fantastic as good as they get. On the way back to the airfield i made an approach, i selected gear down, but unbeknown to me the instructor pulled the circuit breaker for the gear as i selected the lever down. This meant the leaver went down but not the gear. I swear to this day i saw three greens, there were infact no greens. Just like Fly3, i expected to see them so i did. The instructor asked me to check gear two times, each time i looked and said 'brakes off , pin up and in, three greens'. Luckily we had a low speed warner for the gear, we were in a helo so could have come to the hover no problem, non the less it was a big wake up call to someone with 2000 hours on type!!!. I relaxed and saw what i wanted, i got into cognitve failure, i.e when you select the leaver down you always get three greens, and thats exactly what i saw. I have never made that mistake again(made plenty of others though).
The best thing you can do when you screw up is tell people about it, you just might have stopped someone else trying to get airborne flapless - and they may not have been as lucky as you.
Tigs
Good post, you will not make that mistake again well done. Quite a few years ago i was coming back on a check ride (military), the sortie had been fantastic as good as they get. On the way back to the airfield i made an approach, i selected gear down, but unbeknown to me the instructor pulled the circuit breaker for the gear as i selected the lever down. This meant the leaver went down but not the gear. I swear to this day i saw three greens, there were infact no greens. Just like Fly3, i expected to see them so i did. The instructor asked me to check gear two times, each time i looked and said 'brakes off , pin up and in, three greens'. Luckily we had a low speed warner for the gear, we were in a helo so could have come to the hover no problem, non the less it was a big wake up call to someone with 2000 hours on type!!!. I relaxed and saw what i wanted, i got into cognitve failure, i.e when you select the leaver down you always get three greens, and thats exactly what i saw. I have never made that mistake again(made plenty of others though).
The best thing you can do when you screw up is tell people about it, you just might have stopped someone else trying to get airborne flapless - and they may not have been as lucky as you.
Tigs
Jump Complete, a valuable post with lessons to be learnt by everyone. However don’t assume that your ‘oversight’ was just a human error (we all make errors). Review the circumstances of your error, what were the environmental conditions, were there any external pressures (overt or covert), were you fully fit/well, and what was your personal mental state in these circumstances – a need to rush or hurry, to meet the needs of others (to please) or to fulfil personal desires for the enjoyment of flight. There are usually many human aspects behind what appears to be a simple mistake.
It appears that you have learnt a great lesson of airmanship, there are many more to be sought from less sever circumstances; I hope that everyone will heed the circumstances and thus benefit from your shared experience.
Welcome to the annals of ‘ig’ records.
[Edit]
Ig is loosely based on the Ig Nobel Prize.
The science aspects (in italics) are replaced by aviation terms, thus Igs are intended to celebrate the unusual, honour the imaginative, and spur people's interest in aviation safety (science, medicine, and technology) . Something that first makes people laugh then makes them think. This is also related to the annals of improbable human error in aviation (research) , all of which I made up when seeking some humour in aviation safety.
I claim several prizes as someone ‘who holds too many aviation ig records to recall - having made the most flying mistakes that I could and survived’ (see profile).
It appears that you have learnt a great lesson of airmanship, there are many more to be sought from less sever circumstances; I hope that everyone will heed the circumstances and thus benefit from your shared experience.
Welcome to the annals of ‘ig’ records.
[Edit]
Ig is loosely based on the Ig Nobel Prize.
The science aspects (in italics) are replaced by aviation terms, thus Igs are intended to celebrate the unusual, honour the imaginative, and spur people's interest in aviation safety (science, medicine, and technology) . Something that first makes people laugh then makes them think. This is also related to the annals of improbable human error in aviation (research) , all of which I made up when seeking some humour in aviation safety.
I claim several prizes as someone ‘who holds too many aviation ig records to recall - having made the most flying mistakes that I could and survived’ (see profile).
Last edited by alf5071h; 16th May 2005 at 09:08.
Thread Starter
Thank you for all your replies. A few more points:
1) G-ANDY NO, I'm not flying the Army Islanders, this is a civilian drop zone.
2) Linton Chilcott A good point. I did achieve 80kts for the climb out allthough getting a good speed a positive rate of climb took much longer than normal!
3) alf507h I felt fit and not tired at the time. I was not under particular pressure. (P arachute operations tend to run on tight budgets so I try not to prolong getting airborne.)However as we pay for the aircraft brakes off-brakes on and we are usually parked close to the hold, I ususally do power and pre-take off checks before moving, which helps. I have some 750 hours of parachute flying so I am used to resisting the urges to hurry unreasonably!
What does 'ig' records mean?
1) G-ANDY NO, I'm not flying the Army Islanders, this is a civilian drop zone.
2) Linton Chilcott A good point. I did achieve 80kts for the climb out allthough getting a good speed a positive rate of climb took much longer than normal!
3) alf507h I felt fit and not tired at the time. I was not under particular pressure. (P arachute operations tend to run on tight budgets so I try not to prolong getting airborne.)However as we pay for the aircraft brakes off-brakes on and we are usually parked close to the hold, I ususally do power and pre-take off checks before moving, which helps. I have some 750 hours of parachute flying so I am used to resisting the urges to hurry unreasonably!
What does 'ig' records mean?
