Flap retraction
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biz, try not to get personal with this. This is a legitimate thread to have raised and I find it surprising that you (and others) keep telling me that legislation exists which forbids flap retraction below 400 feet and yet nobody has posted it. I've now looked at the 604 as well and its exactly the same as the 601 -chart 06-05-2 applies, final segment climb gradient. Again, the gradient clean outperforms or matches the gradient flapped even with the APR off at Max Continuous so there is no level (third) segment required.
All thats been posted is CFR 14 part 25.111 so let me just deal with that quickly by posting it below. I'm going to state very clearly here that extracting little bits out of regulations like this is actually dangerous and by only quoting the bit that supports your argument and not quoting the stated conditions you are propogating a myth. If you believe that Part25 mandates no flap retraction below 400 feet then you must fail an engine on every take off. I've highlighted the critical statement below.
Sec. 25.111
Takeoff path.
(a) The takeoff path extends from a standing start to a point in the takeoff at which the airplane is 1,500 feet above the takeoff surface, or at which the transition from the takeoff to the en route configuration is completed and VFTO is reached, whichever point is higher. In addition--
(1) The takeoff path must be based on the procedures prescribed in Sec. 25.101(f);
(2) The airplane must be accelerated on the ground to VEF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff; and
(3) After reaching VEF, the airplane must be accelerated to V2.
(b) During the acceleration to speed V2, the nose gear may be raised off the ground at a speed not less than
VR. However, landing gear retraction may not be begun until the airplane is airborne.
(c) During the takeoff path determination in accordance with paragraphs (a) and (b) of this section--
(1) The slope of the airborne part of the takeoff path must be positive at each point;
(2) The airplane must reach V2 before it is 35 feet above the takeoff surface and must continue at a speed as close as practical to, but not less than V2, until it is 400 feet above the takeoff surface;
(3) At each point along the takeoff path, starting at the point at which the airplane reaches 400 feet above the takeoff surface, the available gradient of climb may not be less than--
(i) 1.2 percent for two-engine airplanes;
(ii) 1.5 percent for three-engine airplanes; and
[(iii) 1.7 percent for four-engine airplanes.]
[(4) The airplane configuration may not be changed, except for gear retraction and automatic propeller feathering, and no change in power
or thrust that requires action by the pilot may be made until the airplane is 400 feet above the takeoff surface; and
(5) If Sec. 25.105(a)(2) requires the takeoff path to be determined for flight in icing conditions, the airborne part of the takeoff must be based on the airplane drag:
(i) With the takeoff ice accretion defined in appendix C, from a height of 35 feet above the takeoff surface up to the point where the airplane is 400 feet above the takeoff surface; and
(ii) With the final takeoff ice accretion defined in appendix C, from the point where the airplane is 400 feet above the takeoff surface to the end of the takeoff path.]
(d) The takeoff path must be determined by a continuous demonstrated takeoff or by synthesis from segments. If the takeoff path is determined by the segmental method--
(1) The segments must be clearly defined and must be related to the distinct changes in the configuration, power or thrust, and speed;
(2) The weight of the airplane, the configuration, and the power or thrust must be constant throughout each segment and must correspond to the most critical condition prevailing in the segment;
(3) The flight path must be based on the airplane's performance without ground effect; and
(4) The takeoff path data must be checked by continuous demonstrated takeoffs up to the point at which the airplane is out of ground effect and its speed is stabilized, to ensure that the path is conservative relative to the continuous path.
The airplane is considered to be out of ground effect when it reaches a height equal to its wing span.
(e) For airplanes equipped with standby power rocket engines, the takeoff path may be determined in accordance with section II of appendix E.
I'm getting the Soverign manual today so I'll look at that. Perhaps you could help me by posting the references in the Bombardier manuals that you mentioned.
Thanks
Tom
All thats been posted is CFR 14 part 25.111 so let me just deal with that quickly by posting it below. I'm going to state very clearly here that extracting little bits out of regulations like this is actually dangerous and by only quoting the bit that supports your argument and not quoting the stated conditions you are propogating a myth. If you believe that Part25 mandates no flap retraction below 400 feet then you must fail an engine on every take off. I've highlighted the critical statement below.
Sec. 25.111
Takeoff path.
(a) The takeoff path extends from a standing start to a point in the takeoff at which the airplane is 1,500 feet above the takeoff surface, or at which the transition from the takeoff to the en route configuration is completed and VFTO is reached, whichever point is higher. In addition--
(1) The takeoff path must be based on the procedures prescribed in Sec. 25.101(f);
(2) The airplane must be accelerated on the ground to VEF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff; and
(3) After reaching VEF, the airplane must be accelerated to V2.
(b) During the acceleration to speed V2, the nose gear may be raised off the ground at a speed not less than
VR. However, landing gear retraction may not be begun until the airplane is airborne.
(c) During the takeoff path determination in accordance with paragraphs (a) and (b) of this section--
(1) The slope of the airborne part of the takeoff path must be positive at each point;
(2) The airplane must reach V2 before it is 35 feet above the takeoff surface and must continue at a speed as close as practical to, but not less than V2, until it is 400 feet above the takeoff surface;
(3) At each point along the takeoff path, starting at the point at which the airplane reaches 400 feet above the takeoff surface, the available gradient of climb may not be less than--
(i) 1.2 percent for two-engine airplanes;
(ii) 1.5 percent for three-engine airplanes; and
[(iii) 1.7 percent for four-engine airplanes.]
[(4) The airplane configuration may not be changed, except for gear retraction and automatic propeller feathering, and no change in power
or thrust that requires action by the pilot may be made until the airplane is 400 feet above the takeoff surface; and
(5) If Sec. 25.105(a)(2) requires the takeoff path to be determined for flight in icing conditions, the airborne part of the takeoff must be based on the airplane drag:
(i) With the takeoff ice accretion defined in appendix C, from a height of 35 feet above the takeoff surface up to the point where the airplane is 400 feet above the takeoff surface; and
(ii) With the final takeoff ice accretion defined in appendix C, from the point where the airplane is 400 feet above the takeoff surface to the end of the takeoff path.]
(d) The takeoff path must be determined by a continuous demonstrated takeoff or by synthesis from segments. If the takeoff path is determined by the segmental method--
(1) The segments must be clearly defined and must be related to the distinct changes in the configuration, power or thrust, and speed;
(2) The weight of the airplane, the configuration, and the power or thrust must be constant throughout each segment and must correspond to the most critical condition prevailing in the segment;
(3) The flight path must be based on the airplane's performance without ground effect; and
(4) The takeoff path data must be checked by continuous demonstrated takeoffs up to the point at which the airplane is out of ground effect and its speed is stabilized, to ensure that the path is conservative relative to the continuous path.
The airplane is considered to be out of ground effect when it reaches a height equal to its wing span.
(e) For airplanes equipped with standby power rocket engines, the takeoff path may be determined in accordance with section II of appendix E.
I'm getting the Soverign manual today so I'll look at that. Perhaps you could help me by posting the references in the Bombardier manuals that you mentioned.
Thanks
Tom
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I know perfectly well that Part 25 only addresses OEI performance; however since CS25.111 includes the paragraph
then if you retract the flaps any earlier, in the event of an engine failure you have invalidated the performance calculations.
I have never actually said before in this conversation that there is a regulation about flap retraction per se, I have been pointing to other factors. But you don't seem to be interested in discussing the points raised, you just keep on about your idea without letting facts get in the way.
I'm sorry if you think that's personal, but I am only persevering with this thread because I am worried that there will be people reading it who think that you are advocating a legal, sensible procedure.
(4) Except for gear retraction and
automatic propeller feathering, the aeroplane
configuration may not be changed, and no change
in power or thrust that requires action by the pilot
may be made, until the aeroplane is 122 m (400 ft)
above the take-off surface.
automatic propeller feathering, the aeroplane
configuration may not be changed, and no change
in power or thrust that requires action by the pilot
may be made, until the aeroplane is 122 m (400 ft)
above the take-off surface.
I have never actually said before in this conversation that there is a regulation about flap retraction per se, I have been pointing to other factors. But you don't seem to be interested in discussing the points raised, you just keep on about your idea without letting facts get in the way.
I'm sorry if you think that's personal, but I am only persevering with this thread because I am worried that there will be people reading it who think that you are advocating a legal, sensible procedure.
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You are extracting single lines from the regulations without taking into account the conditions. Thats the same as me quoting the line:-
"The airplane must be accelerated on the ground to VEF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff"
and saying that you therefore have to fail an engine at V1 on every take off. And lets be clear. Are you stating that you can retract the flaps at 400 feet? If so, what are you using for data from that point in the event of a failure?
Yes I certainly am advocating the retraction of flap in accordance with the manufacturers manual. The minimum flap retraction on the 601 is actually 1.25Vs and on the 604 is Vfto+5. Both of these are always below V2+20 so there is already substantial margin built in to the flap retraction speed in the checklist. Biz I simply don't understand where you get the idea that the flaps care how high they are. Can you quote the section in the Bombardier manuals so that I can have a look? I've found the Flight Safety SOP's now which are applied across their training and I believe they are inappropriate for a number of types. Where is works (ie, 400 feet happens to be co-incident with V2+x) it sends completely the wrong message to the pilots about the reason for flap retraction. I don't understand why Flight Safety advocate the use of a 400 foot call to trigger flap retraction. I'll post the SOP so that you can make your own judgement.
"The airplane must be accelerated on the ground to VEF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff"
and saying that you therefore have to fail an engine at V1 on every take off. And lets be clear. Are you stating that you can retract the flaps at 400 feet? If so, what are you using for data from that point in the event of a failure?
Yes I certainly am advocating the retraction of flap in accordance with the manufacturers manual. The minimum flap retraction on the 601 is actually 1.25Vs and on the 604 is Vfto+5. Both of these are always below V2+20 so there is already substantial margin built in to the flap retraction speed in the checklist. Biz I simply don't understand where you get the idea that the flaps care how high they are. Can you quote the section in the Bombardier manuals so that I can have a look? I've found the Flight Safety SOP's now which are applied across their training and I believe they are inappropriate for a number of types. Where is works (ie, 400 feet happens to be co-incident with V2+x) it sends completely the wrong message to the pilots about the reason for flap retraction. I don't understand why Flight Safety advocate the use of a 400 foot call to trigger flap retraction. I'll post the SOP so that you can make your own judgement.
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woo hoo!! posted it! my technical skills are getting better..
Biz you need to tell me why you don't think this is safe or legal. Can you post the regulation please or give an explanation of why this isn't safe? Its what the manuals for many, many aircraft say so if it isn't safe this needs changing immediately.
Biz you need to tell me why you don't think this is safe or legal. Can you post the regulation please or give an explanation of why this isn't safe? Its what the manuals for many, many aircraft say so if it isn't safe this needs changing immediately.
Last edited by tommoutrie; 5th Dec 2012 at 12:10.
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Tom its me who has the sections in the Dassault and BD manuals. Can I suggest that you pass your ideas onto your chief pilot who can if he is unable to explain why you are wrong pass them to your CAA ops inspector.
If the CAA ops inspector can't help then he will pass it to SRG, or whatever they are called now, if they can't help then they can pass it up the line to EASA/ ICAO. It would seem that you are not going to get the answer you want from this thread.
You are playing a spooky game, I like many have been involved in training and examining for a long time, you are on an open forum telling your colleagues in the business world that we are not flying properly. I have often thought some SOP s and Part B stuff was weird but I never taught against it, I have taken it up the chain of command, normally no higher than a fleet manager who has shown me why it's like that.
If your Part B has a profile where you bring the flaps up below 400 feet then your ops inspector agrees with you, sorted, but you would not be posting here if that was the case I guess.
If the CAA ops inspector can't help then he will pass it to SRG, or whatever they are called now, if they can't help then they can pass it up the line to EASA/ ICAO. It would seem that you are not going to get the answer you want from this thread.
You are playing a spooky game, I like many have been involved in training and examining for a long time, you are on an open forum telling your colleagues in the business world that we are not flying properly. I have often thought some SOP s and Part B stuff was weird but I never taught against it, I have taken it up the chain of command, normally no higher than a fleet manager who has shown me why it's like that.
If your Part B has a profile where you bring the flaps up below 400 feet then your ops inspector agrees with you, sorted, but you would not be posting here if that was the case I guess.
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I have done so several times already, but to summarise:
Your profile is illegal because it does not comply with
EU-OPS1.085 f.8 - "The Commander shall....ensure that all operational procedures and check lists are complied with in accordance with the Operations Manual" and I know that your OMB says acceleration altitude is 1500 feet above takeoff.
EU-OPS1.235 - noise abatement procedures. Too long to publish here, but says you need to follow the ICAO profiles, none of which has flap retraction below 800 feet.
I do not think it is sensible because in the first 30 seconds after liftoff the handling pilot should be concentrating on smooth accurate flying without distractions, and I consider configuration changes to be distractions; and people have enough trouble with one engine out procedure without having to remember different ones depending on where they are in the initial climb.
My post from CS25 is not disingenuous, I am merely pointing out the conditions that your performance calculations (for OEI) are based on; if you end up on one engine flaps up below the height that is specified in the calculations, then welcome to the world of test flying.
Your profile is illegal because it does not comply with
EU-OPS1.085 f.8 - "The Commander shall....ensure that all operational procedures and check lists are complied with in accordance with the Operations Manual" and I know that your OMB says acceleration altitude is 1500 feet above takeoff.
EU-OPS1.235 - noise abatement procedures. Too long to publish here, but says you need to follow the ICAO profiles, none of which has flap retraction below 800 feet.
I do not think it is sensible because in the first 30 seconds after liftoff the handling pilot should be concentrating on smooth accurate flying without distractions, and I consider configuration changes to be distractions; and people have enough trouble with one engine out procedure without having to remember different ones depending on where they are in the initial climb.
My post from CS25 is not disingenuous, I am merely pointing out the conditions that your performance calculations (for OEI) are based on; if you end up on one engine flaps up below the height that is specified in the calculations, then welcome to the world of test flying.
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well you don't know my (possibly your) ops manual that well then.
4.2.3 which is entitled Company Standards gives my company minimum flap retraction height as 400 feet.
What I've discussed and the manufacturer suggests is entirely in accordance with both noise abatement profiles. If you fly a correct noise abatement procedure you don't achieve V2+20 (and therefore flap retraction) until 3000 feet. Surprisingly enough, the ICAO noise abatement profile is absolutely in line with the manual. Whats very odd is that hardly anybody actually complies with it!
for those that think the image of the flight safety SOP's was a bit small...
http://email.dropsend.com/wf/click?u...OaSJuorTyc4-3D
4.2.3 which is entitled Company Standards gives my company minimum flap retraction height as 400 feet.
What I've discussed and the manufacturer suggests is entirely in accordance with both noise abatement profiles. If you fly a correct noise abatement procedure you don't achieve V2+20 (and therefore flap retraction) until 3000 feet. Surprisingly enough, the ICAO noise abatement profile is absolutely in line with the manual. Whats very odd is that hardly anybody actually complies with it!
for those that think the image of the flight safety SOP's was a bit small...
http://email.dropsend.com/wf/click?u...OaSJuorTyc4-3D
Last edited by tommoutrie; 5th Dec 2012 at 23:37.
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Sorry, I was looking at Part B, normal takeoff procedure which says accelerate and retract flap at 1500'. This does not conflict with the Part A policy of not below 400' for any type.
But since you've spent 377 posts advocating retracting the flaps as soon as the speed reaches V2+20 regardless of height I'll take that as you agreeing that height is a factor.
I think your reading of the NADP's is a bit creative. From DOC8168:
To be read in conjunction with:
This is for an NADP 2, that has the lowest flap retraction height specificed. NADP1 says reduce thrust and keep climbing with flap to 3000' Also the speed for NADP1 is just "not less than V2+20km/h (10kt)". So I'm not sure how you conclude that V2+20 is not reached until 3000'
And I don't see how whipping the flaps up as soon as the speed reaches V2+20 at 2-300 feet is even remotely compliant.
But regardless of that, you have agreed that your procedure doesn't comply with your Ops Manual, therefore you can't do it. End of story.
But since you've spent 377 posts advocating retracting the flaps as soon as the speed reaches V2+20 regardless of height I'll take that as you agreeing that height is a factor.
I think your reading of the NADP's is a bit creative. From DOC8168:
3.3 The initial climbing speed to the noise abatement initiation point is V2 + 20 to 40 km/h (10 to 20 kt).
3.4 On reaching an altitude equivalent to at least 240 m (800 ft) above aerodrome elevation, decrease aircraft
body angle/angle of pitch while maintaining a positive rate of climb, accelerate towards Vzf and either:
a) reduce power with the initiation of the first flap/slat retraction; or
h) reduce power after flap/slat retraction
3.4 On reaching an altitude equivalent to at least 240 m (800 ft) above aerodrome elevation, decrease aircraft
body angle/angle of pitch while maintaining a positive rate of climb, accelerate towards Vzf and either:
a) reduce power with the initiation of the first flap/slat retraction; or
h) reduce power after flap/slat retraction
k) The maximum acceptable body angle specified for an aeroplane type shall not be exceeded.
And I don't see how whipping the flaps up as soon as the speed reaches V2+20 at 2-300 feet is even remotely compliant.
But regardless of that, you have agreed that your procedure doesn't comply with your Ops Manual, therefore you can't do it. End of story.
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Originally Posted by BizJetJock
Tom, the airlines are 99% of the time using reduced thrust for takeoffs - i.e. matching the thrust used to the weight/altitude/temperature so the problem does not arise. If you have a lightly loaded airliner where they have to use TOGA for takeoff (contaminated runway, antiskid inop, etc.) then you will find that on reaching their pitch limit they allow the speed to increase. On reaching their acceleration altitude if they find that they are already above the minimum flap retraction speed they can do it straight away.
We fly the profile as depicted on the charts, because that is what is expected of us by the airline, the regulator and the passenger.
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That reference is in our part B. Its not from the part A. Its in all our part B's because they were copied from a Citationjet part B and nobody ever bothered to change it even though I pointed it out on all three types I have flown for the company. The Citationjet is certified with a 400 foot platform in the event of an engine failure at V1. Thats why its there.
The point thats been raised about "concentrating on a smooth climb out" and "potentially moving the wrong lever" are only valid if you modify your procedures to leave the gear down until then and change your ops manual to not allow a go-around under 400 feet because the argument just isn't consistent otherwise. Height has nothing whatsoever to do with flaps. Only speed. If you have lost thrust and can't climb at the same time as accelerating you climb first and then use a certified or agreed platform to accelerate then you raise the flaps. This is badly taught, you clearly don't understand it, and neither do quite a lot of others. Some aircraft are actually certified to continue to accelerate to flap retraction in the event of an engine failure (Hawker 4000) but its never taught like that. This means that the pilots lose out on the extra performance gained. Aircraft climb better clean. Aircraft get off the ground in a shorter distance and at a lower speed with flaps. Once away from the ground it is desirable to get rid of the drag and climb. I don't know how to make it any simpler!
My suggestion is absolutely compliant with noise abatement. In a noise abatement climb I hold V2+10to20 therefore I don't raise the flap. At 800 feet I reduce power. At 3000 feet I accelerate through V2+20 and retract the flaps.
Absolutely consistent with every post I have made. Retract the flaps at V2+20. What is your justification for blasting through V2+20 on a noise abatement climb and leaving the flaps down? Body angle? Then reduce the power! Climbing against the excess drag is contrary to the spirit of the noise abatement rules. If you are going to ignore the rules on the basis that body angle and therefore safety is compromised, reduce the power early which will at least reduce the noise and keep with the spirit of the legislation. Everything I am suggesting we do is in the operators manuals, and is supported by the NADP1 and 2. What is your justification for exceeding V2+20 when its clear in the regs and in the ops manual?
The point thats been raised about "concentrating on a smooth climb out" and "potentially moving the wrong lever" are only valid if you modify your procedures to leave the gear down until then and change your ops manual to not allow a go-around under 400 feet because the argument just isn't consistent otherwise. Height has nothing whatsoever to do with flaps. Only speed. If you have lost thrust and can't climb at the same time as accelerating you climb first and then use a certified or agreed platform to accelerate then you raise the flaps. This is badly taught, you clearly don't understand it, and neither do quite a lot of others. Some aircraft are actually certified to continue to accelerate to flap retraction in the event of an engine failure (Hawker 4000) but its never taught like that. This means that the pilots lose out on the extra performance gained. Aircraft climb better clean. Aircraft get off the ground in a shorter distance and at a lower speed with flaps. Once away from the ground it is desirable to get rid of the drag and climb. I don't know how to make it any simpler!
My suggestion is absolutely compliant with noise abatement. In a noise abatement climb I hold V2+10to20 therefore I don't raise the flap. At 800 feet I reduce power. At 3000 feet I accelerate through V2+20 and retract the flaps.
Absolutely consistent with every post I have made. Retract the flaps at V2+20. What is your justification for blasting through V2+20 on a noise abatement climb and leaving the flaps down? Body angle? Then reduce the power! Climbing against the excess drag is contrary to the spirit of the noise abatement rules. If you are going to ignore the rules on the basis that body angle and therefore safety is compromised, reduce the power early which will at least reduce the noise and keep with the spirit of the legislation. Everything I am suggesting we do is in the operators manuals, and is supported by the NADP1 and 2. What is your justification for exceeding V2+20 when its clear in the regs and in the ops manual?
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Perhaps.
But think about this. I'm not trying to re-invent anything. I am suggesting that we do what is in the manual for the aircraft we fly.
I have a concern that current noise abatement procedures are not appropriate for some of the aircraft that we all fly and that many of us do not adhere to the regulations when flying a noise abatement departure. I don't blame the pilots for that at all - the relatively high power to weight of many business jets gives resultant performance which simply does not allow practical adherence to the regulations.
It is abundantly clear even from this thread but also from having worked as a line trainer for many years that the majority of pilots do not understand performance. It is not explicit in flight manuals what actions a pilot should take in the event of an engine failure above flap retraction speed whether the aircraft is clean or still has take off flap selected and many pilots have never even thought about it. I completely accept that I don't know whether it has ever been a factor in an accident but I don't think that's a reason not to consider it. Even discussing it seems to raise a high level of aggression in the responses and I think this is because I am questioning the actions of what pilots do every day. Everyone has got comfortable doing something that I think is flawed - they have been badly taught and do not clearly understand what is going on during the early part of an all engines operating take off. Exceeding the flap retraction speed by a significant amount degrades the take off path performance. This manifests itself as increased noise footprint when operating with all engines or as a degraded flight path in the event of a failure above the flap retraction speed.
I started this thread because I have been flying for an operator who has attempted to mandate climbing to 1500 feet holding the take off flap setting whilst accelerating to near Vfe. Quite clearly this is bonkers but in trying to get this situation changed I became aware of how deeply ingrained the idea that a flap retraction height controls the retraction of flaps is.
There is no such thing as a flap retraction height. This idea is actually dangerous. Acceleration altitudes exist which allow you to accelerate the aircraft should you require it in order to retract the flaps but a pilot does not retract the flaps because they are at a specific altitude. The flaps are retracted because the aircraft has achieved a specific speed.
My argument is that you do the SAME THING with regard to the flaps regardless of whether you lose an engine at V1, V2, V2+20, V2+50, on a noise abatement departure, on a normal (non noise) departure. I am certain that this is what is intended by manufacturers and it fits all the written legislation.
I am astonished that so many pilots have come back with initially fierce arguments without even beginning to carefully consider what we are really talking about. Its been clear that some pilots think you keep the flap set at take off and climb to 1500 feet, some think you can retract the flaps at 400 feet but have not been specific about what data they are using for this. Very few have been specific about their actions in the event of a failure above V2+20 and where they have done so I believe those actions are not supported by the flight manual.
So that's why I'm bothered about it. I've met too many pilots who don't really know what they would do in that phase of flight and don't understand the noise implications and fuel implications should everything go to plan. Worse than that, I've met trainers who will positively teach the wrong thing simply because they don't really understand it. And it all goes back to how they were taught in the first place.
But think about this. I'm not trying to re-invent anything. I am suggesting that we do what is in the manual for the aircraft we fly.
I have a concern that current noise abatement procedures are not appropriate for some of the aircraft that we all fly and that many of us do not adhere to the regulations when flying a noise abatement departure. I don't blame the pilots for that at all - the relatively high power to weight of many business jets gives resultant performance which simply does not allow practical adherence to the regulations.
It is abundantly clear even from this thread but also from having worked as a line trainer for many years that the majority of pilots do not understand performance. It is not explicit in flight manuals what actions a pilot should take in the event of an engine failure above flap retraction speed whether the aircraft is clean or still has take off flap selected and many pilots have never even thought about it. I completely accept that I don't know whether it has ever been a factor in an accident but I don't think that's a reason not to consider it. Even discussing it seems to raise a high level of aggression in the responses and I think this is because I am questioning the actions of what pilots do every day. Everyone has got comfortable doing something that I think is flawed - they have been badly taught and do not clearly understand what is going on during the early part of an all engines operating take off. Exceeding the flap retraction speed by a significant amount degrades the take off path performance. This manifests itself as increased noise footprint when operating with all engines or as a degraded flight path in the event of a failure above the flap retraction speed.
I started this thread because I have been flying for an operator who has attempted to mandate climbing to 1500 feet holding the take off flap setting whilst accelerating to near Vfe. Quite clearly this is bonkers but in trying to get this situation changed I became aware of how deeply ingrained the idea that a flap retraction height controls the retraction of flaps is.
There is no such thing as a flap retraction height. This idea is actually dangerous. Acceleration altitudes exist which allow you to accelerate the aircraft should you require it in order to retract the flaps but a pilot does not retract the flaps because they are at a specific altitude. The flaps are retracted because the aircraft has achieved a specific speed.
My argument is that you do the SAME THING with regard to the flaps regardless of whether you lose an engine at V1, V2, V2+20, V2+50, on a noise abatement departure, on a normal (non noise) departure. I am certain that this is what is intended by manufacturers and it fits all the written legislation.
I am astonished that so many pilots have come back with initially fierce arguments without even beginning to carefully consider what we are really talking about. Its been clear that some pilots think you keep the flap set at take off and climb to 1500 feet, some think you can retract the flaps at 400 feet but have not been specific about what data they are using for this. Very few have been specific about their actions in the event of a failure above V2+20 and where they have done so I believe those actions are not supported by the flight manual.
So that's why I'm bothered about it. I've met too many pilots who don't really know what they would do in that phase of flight and don't understand the noise implications and fuel implications should everything go to plan. Worse than that, I've met trainers who will positively teach the wrong thing simply because they don't really understand it. And it all goes back to how they were taught in the first place.
Last edited by tommoutrie; 6th Dec 2012 at 13:12.
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Originally Posted by TomMoutrie
The point thats been raised about "concentrating on a smooth climb out" and "potentially moving the wrong lever" are only valid if you modify your procedures to leave the gear down until then and change your ops manual to not allow a go-around under 400 feet because the argument just isn't consistent otherwise. Height has nothing whatsoever to do with flaps. Only speed.
What I was tying to suggest was de-linking the action of retracting the gear along side retracting the flap would be a good thing. If you take off safe in the knowledge that you have excess performance and in the knowledge that you can normally retract the flaps as soon as the gear is up, thats what you will start (subconsciously) doing. How do you then know that on a go-around you won't retract gear and flaps (entirely) at the same time? This is human factors and where I was coming from with my first post, a long time ago.
In our operation on the go around, gear and flaps are de linked with SOP's. We perform G/A actions (power+pitch), then move flaps, then check the aircraft has entered correct modes, then raise gear. Nothing is done in a rush...
Lets face it, gear up is normally 2-3 seconds after take off. If you climb at (guess mode) 4000 fpm, it will take you 6 seconds to get to 400'. Why are you in such a hurry to get anything done in that 6 seconds? Maybe, your 1500' operator just simply wants concentration on the initial climb ensuring stability over a rushed operation and in doing so they have made a choice of safety over outright efficiency...
BTW, from a purely performance perspective, I can't disagree with anything you are suggesting. From a flight safety one I most certainly do... And that's my opinion!
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gents I certainly don't mean to offend anyone by saying that we've been taught badly. I think there is a systemic fault in the training of pilots which tends towards teaching the minimums. Its an exam passing mentality that's becoming worse the more the industry relies on individuals to pay for their training. Even once we've passed and got jobs the emphasis of training is only to repeat the standard we achieved the day we scraped through the IR. And for subsequent courses there is a massive amount of repetition - how many courses have you sat through that are exactly the same stuff you sat through the year before. The emphasis should always be on continual learning rather than an annual LPC hurdle. Most pilots are expected to learn all the periphal information by osmosis. Ask most guys where do download OPS1 or how to look at ICAO 8168 or what it even is and you'll end up with a blank look. How EASA is supposed to work, what comes under the remit of the DFT, the list of things we could actually learn about is endless.
I also think that various bits of legislation are invented without real consideration to operational practicality (noise being one). I have 5 years experience as an acoustic engineer and I understand enough about noise and vibration to know that the current rules are daft. I don't even know who sit's round a table and makes these rules up. Where did the "land within 60% of the LDA" for turbo jets come from and whats the maths behind it? Why is it 70% for turboprops? I just don't understand the maths and the logic.
Anyway, I thought I'd start with this and your suggestion of talking to SRG is a good one so I'm happy to end the rather pointless bickering on here and let you know how I get on.
Cheers all
Tom
I also think that various bits of legislation are invented without real consideration to operational practicality (noise being one). I have 5 years experience as an acoustic engineer and I understand enough about noise and vibration to know that the current rules are daft. I don't even know who sit's round a table and makes these rules up. Where did the "land within 60% of the LDA" for turbo jets come from and whats the maths behind it? Why is it 70% for turboprops? I just don't understand the maths and the logic.
Anyway, I thought I'd start with this and your suggestion of talking to SRG is a good one so I'm happy to end the rather pointless bickering on here and let you know how I get on.
Cheers all
Tom
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It is abundantly clear even from this thread but also from having worked as a line trainer for many years that the majority of pilots do not understand performance. It is not explicit in flight manuals what actions a pilot should take in the event of an engine failure above flap retraction speed whether the aircraft is clean or still has take off flap selected and many pilots have never even thought about it. I completely accept that I don't know whether it has ever been a factor in an accident but I don't think that's a reason not to consider it
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Tommie, I think you've won the argument, but there are some vociferous posters who will never accept anything unless it's quoted in the regs that they seem so anxious to quote.
If you have the charts to back up your knowledge that the airplane will make a better gradient with the flaps retracted should an engine quit, in my opinion it makes good sense to retract the flaps as soon as you gain the known advantage. Doing so may even reduce the noise footprint, but even if it doesn't one could surely argue that you are enhancing the performance of your aircraft as a preemptive safety measure to increase the obstacle clearance margin should an engine quit. Who could possibly argue with that?
On the other hand it isn't really fair to criticise those who like to highlight obscure, non performance related regulatory text - these posters, in the main, are likely to be the product of a training regime that prioritises the teaching of regulatory compliance above the practicalities of "real world" aircraft operations. Unfortunately we live in a blame culture bubble, and its quite easy to see why the regulators have to cover their backsides too.
Rules are for the guidance of the wise, and the obedience of fools.
If you have the charts to back up your knowledge that the airplane will make a better gradient with the flaps retracted should an engine quit, in my opinion it makes good sense to retract the flaps as soon as you gain the known advantage. Doing so may even reduce the noise footprint, but even if it doesn't one could surely argue that you are enhancing the performance of your aircraft as a preemptive safety measure to increase the obstacle clearance margin should an engine quit. Who could possibly argue with that?
On the other hand it isn't really fair to criticise those who like to highlight obscure, non performance related regulatory text - these posters, in the main, are likely to be the product of a training regime that prioritises the teaching of regulatory compliance above the practicalities of "real world" aircraft operations. Unfortunately we live in a blame culture bubble, and its quite easy to see why the regulators have to cover their backsides too.
Rules are for the guidance of the wise, and the obedience of fools.
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It's so disheartening to discover that, after 20,000hrs, I am one of the fools that have been doing it all wrong by climbing out on the recommended vertical profile.
Of course! I should have ignored the AFMs, the test pilots, the company SOPs and those stupid regulatory authorities, and listened to these real experts on pprune.
It must be pure bloody luck that I haven't hit that mountain on climb out.
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Of course! I should have ignored the AFMs, the test pilots, the company SOPs and those stupid regulatory authorities, and listened to these real experts on pprune.
It must be pure bloody luck that I haven't hit that mountain on climb out.
6