Flap retraction
Join Date: Jan 2008
Location: MAN
Posts: 769
Likes: 0
Received 0 Likes
on
0 Posts
Oh and the 1,500 is the end of the takeoff path if anyone wonders where that number comes from, unless the enroute altititude is below that, can't think of an airport that has an enroute segment below 1,500 but wait to stand corrected on that one.
Let me correct myself here.
Takeoff path.
“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"
Let me correct myself here.
Takeoff path.
“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"
Last edited by cldrvr; 19th Nov 2012 at 12:16.
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
FAR 25 section 111 and JAR 25 certification are both in the event of the failure of the most critical powerplant. It says so right at the top. Also, it makes sense. If all the engines are running you can raise the flap at the flap up speed. This is where the confusion comes from and is why FSI teach it so badly. They spend all their time teaching people to fly away with one engine out and virtually no time at all teaching people to take advantage of all them jets..
This is the reason that no manufacturer mentions 400 feet during an all engines operating departure.
Is a two way bet and I'm two grand up now. Cheque going to the dogs home.
This is the reason that no manufacturer mentions 400 feet during an all engines operating departure.
Is a two way bet and I'm two grand up now. Cheque going to the dogs home.
Last edited by tommoutrie; 19th Nov 2012 at 12:23.
Join Date: Mar 2004
Location: schermoney and left front seat
Age: 57
Posts: 2,438
Received 0 Likes
on
0 Posts
Do you fairly smartly go from flap land to whatever the take off setting is or sit about for a bit, just in case?
Apples and Oranges....going from Flaps 7° or 15° to 0°, or 35° to 15°....from 35° to 15° you more or less just reduce drag, from 15° or 7° to 0° its more about lift, IIRC...
And in the checklist is says:
All Engine Go-Around
1. Go-Around Button (either throttle)..................... Push
2. Throttles ....................................TO Detent
3. Airplane Pitch Attitude........................ 7.5°Initially
(FD go-around command), then As Required
4. Flaps............................................ 15°
5. ClimbSpeed..................................... VAPP
6. LandingGear ......................................UP
And here we go again:
7. Flaps........................... 0°(VAPP+10knots and at or above 400 feet AGL)
8. Airspeed..................................As Required
9. Throttle ...................... MCT Detentor As Required
10. YawDamper................................ As Desired
11. Autopilot ................................... As Desired
BTW, from 7° to 0° takes ages, even If I´d be half as alert as you are and change the setting ASAP (say at 200ft minimums), the flaps wouldn´t be in below 1000-ft...
Don Quixote Impersonator
Join Date: Jul 1999
Location: Australia
Age: 77
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
My Friends
Don't get confused, it's 400/1500 ABOVE THE TAKE OFF SURFACE.
We like FSI insist that after V1 commit, the crew "figuratively" or mentally sit on their hands until you get to 400ft ABOVE the take off surface, from a certification viewpoint there is no requirement for any action including EFATO actions and it reduces the opportunity for fumble thumbs and provides for an orderly, thoughtful and disciplined reaction.
The certification rules and the jet turbine now provide the opportunity to avoid a reactive response, denied Part 23 pilots and the old CAR 4 types where quick but accurate responses often meant the difference between hero or zero.
Tom, thanks for the stimulation but I'm not yet sure about who owns the grand.
Don't get confused, it's 400/1500 ABOVE THE TAKE OFF SURFACE.
We like FSI insist that after V1 commit, the crew "figuratively" or mentally sit on their hands until you get to 400ft ABOVE the take off surface, from a certification viewpoint there is no requirement for any action including EFATO actions and it reduces the opportunity for fumble thumbs and provides for an orderly, thoughtful and disciplined reaction.
The certification rules and the jet turbine now provide the opportunity to avoid a reactive response, denied Part 23 pilots and the old CAR 4 types where quick but accurate responses often meant the difference between hero or zero.
Tom, thanks for the stimulation but I'm not yet sure about who owns the grand.
Last edited by gaunty; 19th Nov 2012 at 12:26.
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
hey... that wouldnt be a flight safety checklist would it?
and CLdriver
straight out of the FAR's, 25.111, I draw your attention to note 2 in the conditions for the net take off 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 §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 --
and CLdriver
straight out of the FAR's, 25.111, I draw your attention to note 2 in the conditions for the net take off 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 §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 --
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
everybody is happy with what happens if the engine fails at V1 because thats what we all spend a load of time learning about. But we don't properly consider what happens if it fails a bit further up the take off path and often don't even have figures for what happens if, god forbid, all the engines keep running.
If an engine fails above the flap up speed it doesnt matter where you are in the takeoff path the airframe should be clean. Thats part of why this matters. Lots of folk are well above and are still dirty. Often they have reduced the power a bit to contain the climb and if a powerplant then fails they are well into the draggy bit of the curve. Because they've reduced the power to hold the deck angle and keep the climb rate sensible they now have to set max cont and focus hard to get the aircraft back to V2 to make sure they are climbing properly. Where are they on the vertical SID profile? nobody knows..
If they are clean at the point where it fails they still have to set max cont on the remaining power plant but only have to come back to V2+10 or in reality, Venr. They will climb better than they would flapped and are in a better position because they had to reduce speed by a smaller amount and therefore incurred less of a drag penalty.
There is no downside in doing it correctly!
(be honest, has this got you thinking..)
If an engine fails above the flap up speed it doesnt matter where you are in the takeoff path the airframe should be clean. Thats part of why this matters. Lots of folk are well above and are still dirty. Often they have reduced the power a bit to contain the climb and if a powerplant then fails they are well into the draggy bit of the curve. Because they've reduced the power to hold the deck angle and keep the climb rate sensible they now have to set max cont and focus hard to get the aircraft back to V2 to make sure they are climbing properly. Where are they on the vertical SID profile? nobody knows..
If they are clean at the point where it fails they still have to set max cont on the remaining power plant but only have to come back to V2+10 or in reality, Venr. They will climb better than they would flapped and are in a better position because they had to reduce speed by a smaller amount and therefore incurred less of a drag penalty.
There is no downside in doing it correctly!
(be honest, has this got you thinking..)
Join Date: Jan 2008
Location: MAN
Posts: 769
Likes: 0
Received 0 Likes
on
0 Posts
Tm, don't have the regs to hand here so can't give you the exact reference until later tonight.
Have a look at the AMC, I am 99% sure on the top of my head that there is a reference to all engine operating in there with regards to the 400'.
If you don't have a copy to hand, I will post the reference later here.
Have a look at the AMC, I am 99% sure on the top of my head that there is a reference to all engine operating in there with regards to the 400'.
If you don't have a copy to hand, I will post the reference later here.
Moderator
I went through this discussion with a company pilot who was right seat to me during Caravan flight testing I was doing. The company pilot was horror struck when I retracted the flaps from 20 to 10 as I accelerated through the appropriate speed, irrespective of altitude - on a deliberately flat takeoff. He was so shaken by this, he had trouble expressing his concern. I bit shaken myself from his reaction, I went back to the Flight Manual, to be sure I had no missed something important during my first read. Nope, no reference to a minimum AGL for flap retraction, so I had flown the aircraft within the terms of the Flight Manual. He was annoyed when I pointed that out to him. "But... but.. what if you'd had an engine failure...?". "Well, I'd rather enter a glide with less drag, so if the speed is right, I would rather have the lesser amount of flaps extended. I can re-extend them any time I want". He did not agree, but could not present an argument to this logic either. He decided to stop his resistance when I pointed out that the Flight Manual states for a balked landing (which is kind of like a takeoff) to retract the flaps to 20 right after you apply power - not wait for any particular altitude before a configuration change!
The quoted FAR is a design requirement, it is not an operational regulation. The aircraft must demonstrate the stated capability, that FAR is not telling you that you have to fly it that way, just that it can be done.
If a Flight Manual tells you that you must or should, then you should. If the person who owns the plane says "fly it this way" then you should if you want to keep your employer happy. Otherwise, fly the plane safely, operate the flaps within the limiting speeds, and select the flaps as you require them.
The quoted FAR is a design requirement, it is not an operational regulation. The aircraft must demonstrate the stated capability, that FAR is not telling you that you have to fly it that way, just that it can be done.
If a Flight Manual tells you that you must or should, then you should. If the person who owns the plane says "fly it this way" then you should if you want to keep your employer happy. Otherwise, fly the plane safely, operate the flaps within the limiting speeds, and select the flaps as you require them.
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
is nobody else seeing a common thread here...
how the hell did pythagoras convince the people that the earth was an oblate spheroid? oh wait... that happened a thousand years later when Magellen sailed round it..
why is there a slavish addiction to a rule that's painfully obviously rubbish just because its what we all thought was right? This is a bad industry to just blindly accept what you're told. Its important to actually understand.
Still up for the bet.
how the hell did pythagoras convince the people that the earth was an oblate spheroid? oh wait... that happened a thousand years later when Magellen sailed round it..
why is there a slavish addiction to a rule that's painfully obviously rubbish just because its what we all thought was right? This is a bad industry to just blindly accept what you're told. Its important to actually understand.
Still up for the bet.
Last edited by tommoutrie; 19th Nov 2012 at 13:12.
Join Date: Mar 2004
Location: schermoney and left front seat
Age: 57
Posts: 2,438
Received 0 Likes
on
0 Posts
Where are they on the vertical SID profile? nobody knows..
By how much I´m above a required altitude is not really of interest, IMHO.
They have enough speed to come back gently to V2 whilst adding power back to MCT.
Q.: what do you do if you need, say, a 6% gradient to 7000ft above the airport, you depart, collect your flaps at 400ft, set MCT & accelarate in the climb and then eat a goose at 2000ft. Lets say your at 160 KIAS at the time, V2 would be 116 and Venr 180.
Do you accelerate to Venr or pull back to V2 and reset flaps? Or V2 without flaps? Or just stay at the present speed?
it's worse than talking to my teenage daughters.
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
You do exactly what it says in the manual. You should have taken the flap at V2+10 (is it for the soverign?) so you should be clean. You are above 1500 feet so you confirm which one had gone bang, select MCT on the other one and an appropriate pitch for Venr or dial it into FLC and continue the climb for 7000 feet.
The airframe climbs better clean than it does with flap. You take off with flap to reduce the take off roll and keep the groundspeed down for the tyres and to make sure the brakes can cope with an RTO. Once in the air and above the speed that you can retract them you get rid of them because now they are only producing extra drag.
If this stuff was taught properly it wouldn't even be a question.
The airframe climbs better clean than it does with flap. You take off with flap to reduce the take off roll and keep the groundspeed down for the tyres and to make sure the brakes can cope with an RTO. Once in the air and above the speed that you can retract them you get rid of them because now they are only producing extra drag.
If this stuff was taught properly it wouldn't even be a question.
Last edited by tommoutrie; 19th Nov 2012 at 13:33.
Thread Starter
Join Date: Jan 2002
Location: london, UK
Age: 57
Posts: 550
Likes: 0
Received 0 Likes
on
0 Posts
on the bright side, if we sort this out now we don't have to think about it when it happens!
out of interest, does anyone actually agree with me?
out of interest, does anyone actually agree with me?
ECON cruise, LR cruise...
Join Date: Apr 2002
Location: MIRSI hold - give or take...
Age: 52
Posts: 568
Likes: 0
Received 0 Likes
on
0 Posts
Tom,
I think that through our combined sheer disbelief, FSI indoctrination or desire to retire with licenses still intact, a majority here might well be against the motion.
There seems to be 2 distinct issues at play here:
1) Operators flying all-engines operating with a fixed pitch and getting alarmingly close to VFE before retracting flaps on a normal departure.
2) The aerodynamic efficacy of the aircraft operating at V2-V2+10 with TO flaps vs V2+whatever clean
Now, issue 1 - can deffo see where you are coming from. Have flown everything from B737, CL30, EMB Legacy and CL850, and in all of these airframes, "Gear UP - Level Change" has produced acceptable attitudes, V2+15-20-ish and acceptable ROCs. Fixed pitch is bad for noise, fuel, path and turn radius - so am fully with you on the idea that on a normal TO, flying V2+80 and flaps TO is a kaka idea.
Issue 2 - still not buying it. From an aerodynamic POV you might very well be right, but with no way of making the manufacturer accept your evidence. They all have 2 ways of climbing OEI:
1) V2 and Flaps TO (or back to V2+10 if failure occurred after this speed)
2) Vfto and Flaps 0
Now, apart from waving Ockhams Razor at you - suggesting that the simplest explaination for OEMs chosing Vfto as your clean climb-speed because this is the most effective gradient speed, thus having the best performing and thus best selling aircraft they can - I simply must disagree with the idea of flying the aircraft in a radically different configuration than the OEM tells you to, especially just after losing one engine. This apart from the arguments stated in my previous post...
If the G650 AFM says gear+flaps up at the same time, then so be it, and that aircraft then needs to be flown accordingly. However, if it is just the 650 checklist that states this, then this is merely the sequence you check things in, not necessarily indicating a temporal relationship between when you legally can retract the gear, respectively the flaps. On the 850 checklist, "Gear and Flaps" is one check-item but by no means one do-item ;-)
It may be more efficient going clean @ V2+whatever - but why would I do it? I check for each and every departure that I can clear all obstacles using the AFM speeds and configuration, so I would gain nothing by going down the path you suggest. I cannot lift more mass out of a given runway, but by using non-standard procedures I leave myself wide open to attack from lawyers, to career-ending rumours about my person and ridicule from my peers.
In other words - you may have an aerodynamically point, but from an operational point it's a non-starter.
Payment by cash or cheque accepted
I think that through our combined sheer disbelief, FSI indoctrination or desire to retire with licenses still intact, a majority here might well be against the motion.
There seems to be 2 distinct issues at play here:
1) Operators flying all-engines operating with a fixed pitch and getting alarmingly close to VFE before retracting flaps on a normal departure.
2) The aerodynamic efficacy of the aircraft operating at V2-V2+10 with TO flaps vs V2+whatever clean
Now, issue 1 - can deffo see where you are coming from. Have flown everything from B737, CL30, EMB Legacy and CL850, and in all of these airframes, "Gear UP - Level Change" has produced acceptable attitudes, V2+15-20-ish and acceptable ROCs. Fixed pitch is bad for noise, fuel, path and turn radius - so am fully with you on the idea that on a normal TO, flying V2+80 and flaps TO is a kaka idea.
Issue 2 - still not buying it. From an aerodynamic POV you might very well be right, but with no way of making the manufacturer accept your evidence. They all have 2 ways of climbing OEI:
1) V2 and Flaps TO (or back to V2+10 if failure occurred after this speed)
2) Vfto and Flaps 0
Now, apart from waving Ockhams Razor at you - suggesting that the simplest explaination for OEMs chosing Vfto as your clean climb-speed because this is the most effective gradient speed, thus having the best performing and thus best selling aircraft they can - I simply must disagree with the idea of flying the aircraft in a radically different configuration than the OEM tells you to, especially just after losing one engine. This apart from the arguments stated in my previous post...
If the G650 AFM says gear+flaps up at the same time, then so be it, and that aircraft then needs to be flown accordingly. However, if it is just the 650 checklist that states this, then this is merely the sequence you check things in, not necessarily indicating a temporal relationship between when you legally can retract the gear, respectively the flaps. On the 850 checklist, "Gear and Flaps" is one check-item but by no means one do-item ;-)
It may be more efficient going clean @ V2+whatever - but why would I do it? I check for each and every departure that I can clear all obstacles using the AFM speeds and configuration, so I would gain nothing by going down the path you suggest. I cannot lift more mass out of a given runway, but by using non-standard procedures I leave myself wide open to attack from lawyers, to career-ending rumours about my person and ridicule from my peers.
In other words - you may have an aerodynamically point, but from an operational point it's a non-starter.
Payment by cash or cheque accepted