A320 Flap overspeed during retraction?
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A320 Flap overspeed during retraction?
In case of flap retraction at 'S' spd during take off, sometimes spd increase over 230kts(flap 1 limit spd) during flap retraction.
Can we consider we committed flap overspeed in this case? We can encounter this situation several times especially in heavy weight takeoff situation.
How's your thought?
In my company, this is big issue now because by this case a pilot failed his checkride transitioning to captain.
Can we consider we committed flap overspeed in this case? We can encounter this situation several times especially in heavy weight takeoff situation.
How's your thought?
In my company, this is big issue now because by this case a pilot failed his checkride transitioning to captain.
Last edited by FlywithPark; 23rd Jun 2013 at 08:37.
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S Speed.
So you are saying that "S" speed in your case is too fast for Flap Retraction?
Well until you hear further do not retract below "S" speed especially - if heavy weight.
Well until you hear further do not retract below "S" speed especially - if heavy weight.
Last edited by Natstrackalpha; 23rd Jun 2013 at 09:03.
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think what he's saying is the "s" speed is so close to vfe, that during acceleration and flap retraction, the slats don't quite get out of the way before the airplane hits 230 KTS...simple solution is to speed select 230 kts on the MCP..
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Just wondering, thought the A320 has a flap auto retract feature when the speed reaches 215 Kts leaving only the slats extended. Hence the only device that would overspeed is the slats. Puzzled..
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Airbus says: PNF selects the FLAPS lever position and replies " FLAPS ONE"after checking the blue number on the ECAM flaps indicator to confirm the correct selection has been made.
To my mind this is a non event if the flaps position indicator went blue before speed reached VFE.
Hence the VMO/MMO changes to the next relevant one as soon as the indicator colours in blue.
Furthermore, your coworker would get an overspeed.
If he did not... Well he can complain.
To my mind this is a non event if the flaps position indicator went blue before speed reached VFE.
Hence the VMO/MMO changes to the next relevant one as soon as the indicator colours in blue.
Furthermore, your coworker would get an overspeed.
If he did not... Well he can complain.
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Originally Posted by ironbutt
simple solution is to speed select 230 kts on the MCP..
Seriously, I recall early 733/4 'company mandated' VNAV accel days we sometimes programmed 230 at 3000' into the FMC and deleted or went MCP when clean.
Ut Sementem Feeceris
Heavy weight, allow the aircraft to accelerate normally towards 'S' speed which will possibly result in auto-flap retraction i.e. from 1+F to 1 (slats only). Approaching Green Dot, select flap 0 and MONITOR acceleration towards 230 compared to Slat retract speed.
If in doubt, PULL SPD at, say, 225-228 knots, when the slats are in, MANAGE SPD, no-overspeed. Job done.
If in doubt, PULL SPD at, say, 225-228 knots, when the slats are in, MANAGE SPD, no-overspeed. Job done.
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flywithPark
S speed for 78T TOW is 211KTS. So there is good 19KTS to VFE, lesser TOW will have even higher margin. So since you are aware that overspeed may occur when you see slat auto retraction at 210kt if you also select flap zero you should not have a problem. A4 suggestion is not good because green dot speed beyond 72T is higher than 230KTS and will lead to overspeed.Offcourse flying select 220 or so is always possible.
S speed for 78T TOW is 211KTS. So there is good 19KTS to VFE, lesser TOW will have even higher margin. So since you are aware that overspeed may occur when you see slat auto retraction at 210kt if you also select flap zero you should not have a problem. A4 suggestion is not good because green dot speed beyond 72T is higher than 230KTS and will lead to overspeed.Offcourse flying select 220 or so is always possible.
Last edited by vilas; 23rd Jun 2013 at 12:17.
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auto retraction.....
Vilas....
the slats do not auto retract at 210 kts, the flaps do !
With an S speed higher than 210kts, the flap lever should be moved to the 0 position at S speed assuming the aircraft is accelerating. This means that the flaps will already be travelling, followed by the slats commanded by the flap lever position.
The FCTM makes no mention of SPD select to control the IAS at or below FLAP limit speed of 230Kts. It is also going to be pretty close to GD, however, there is also nothing to say that you can't fly below GD speed withouit selecting flap 1. Airbus just don't recommend it !
In turbulent conditions, it may be impossible to control the speed at or below 230 Kts before the slats have completely retracted. It is transient in most cases and short term.
What would the check Captain prefer.... flying below green dot clean or the slats retracting the final few degrees with a decreasing aerodynamic load passing 230Kts.
the slats do not auto retract at 210 kts, the flaps do !
With an S speed higher than 210kts, the flap lever should be moved to the 0 position at S speed assuming the aircraft is accelerating. This means that the flaps will already be travelling, followed by the slats commanded by the flap lever position.
The FCTM makes no mention of SPD select to control the IAS at or below FLAP limit speed of 230Kts. It is also going to be pretty close to GD, however, there is also nothing to say that you can't fly below GD speed withouit selecting flap 1. Airbus just don't recommend it !
In turbulent conditions, it may be impossible to control the speed at or below 230 Kts before the slats have completely retracted. It is transient in most cases and short term.
What would the check Captain prefer.... flying below green dot clean or the slats retracting the final few degrees with a decreasing aerodynamic load passing 230Kts.
Last edited by Luckyguy; 23rd Jun 2013 at 12:41.
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Luckyguy
Sorry I wrote slat by mistake offcourse it is flaps retraction. But i don't understand where does green dot come in while retracting slat. As long as you are accelerating at S speed you retract to flap zero. You don't wait for GD to retract slats/flaps. As far as flying below green dot is another issue. Airbus permits flying below GD. All speeds upto VLS are flyable. Only thing changes is the bank angle at which high angle of attack protection will be triggered. Below GD it is reduced 40 degrees of bank.
Sorry I wrote slat by mistake offcourse it is flaps retraction. But i don't understand where does green dot come in while retracting slat. As long as you are accelerating at S speed you retract to flap zero. You don't wait for GD to retract slats/flaps. As far as flying below green dot is another issue. Airbus permits flying below GD. All speeds upto VLS are flyable. Only thing changes is the bank angle at which high angle of attack protection will be triggered. Below GD it is reduced 40 degrees of bank.
Last edited by vilas; 23rd Jun 2013 at 13:02.
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GD
Green dot only comes into it as a coincident speed at that weight. If you control SPD from the FCU to below GD, whilst trying to avoid a flap\slat overspeed (which may only be a very small number of knots), you quite possibly end up clean below GD and maintaining that SPD as it's selected. Calm conditions at that weight and pulling SPD 230Kts, the auotpilot or ace pilot doing a fine job and all is well. That's all I was trying to say.
As I said, you can fly a SPD below GD clean, Mr Airbus, as told to me by a nice man at TLS, don't recommend it for the obvious reasons !
Cheers
As I said, you can fly a SPD below GD clean, Mr Airbus, as told to me by a nice man at TLS, don't recommend it for the obvious reasons !
Cheers
Ut Sementem Feeceris
Vilas, don't forget that 'F' and 'S' speeds are the MINIMUM speeds that flap should be retracted at. With a positive speed trend there is nothing wrong with retracting at S+10 knots - you're giving yourself a buffer and when you move the lever you're going to be almost at GD speed. This is not so critical on lower weight departures but at higher weight takeoffs the cleanup needs to be more "efficient" in terms if energy maintenance and using speed TREND effectively.
Alpha lock will only prevent the SLATS from retracting if the AoA is greater than the limit at the moment the lever is moved. Once the SLATS are retracting the will keep going. So only select FLAP 0 with a nice positive speed trend and a buffer - if hand flying it is easy to "adjust" the speed trend line with sidestick to prevent an overspeed - it's called aviating
To clarify my earlier post, selecting say 225-228 knots is a momentary "fix" whilst the last few seconds of SLAT retraction occur - your hand wouldn't even come off the FCU SPD knob. Thrust will not reduce because you will be in THR CLB and as soon as you're clean, PUSH for MANAGED speed the attitude will reduce to facilitate acceleration to 250knots / climb speed.
@gAMbl3 - because at very high weights you could end being clean well below GD. Additionally the pitch to maintain 215 may well put you above the AoA threshold for Alpha Lock in turbulent conditions. Keep the energy/speed/trend positive, watch the SLATS as they retract on the E/WD, intervene / manage as required.......it's what we're paid to do.....fly the aircraft safely within its limits.
Alpha lock will only prevent the SLATS from retracting if the AoA is greater than the limit at the moment the lever is moved. Once the SLATS are retracting the will keep going. So only select FLAP 0 with a nice positive speed trend and a buffer - if hand flying it is easy to "adjust" the speed trend line with sidestick to prevent an overspeed - it's called aviating
To clarify my earlier post, selecting say 225-228 knots is a momentary "fix" whilst the last few seconds of SLAT retraction occur - your hand wouldn't even come off the FCU SPD knob. Thrust will not reduce because you will be in THR CLB and as soon as you're clean, PUSH for MANAGED speed the attitude will reduce to facilitate acceleration to 250knots / climb speed.
@gAMbl3 - because at very high weights you could end being clean well below GD. Additionally the pitch to maintain 215 may well put you above the AoA threshold for Alpha Lock in turbulent conditions. Keep the energy/speed/trend positive, watch the SLATS as they retract on the E/WD, intervene / manage as required.......it's what we're paid to do.....fly the aircraft safely within its limits.
Last edited by A4; 23rd Jun 2013 at 13:31.
Whereas VFE on the PFD is displayed according to the position of the flaps lever, the audio/ECAM warning is triggered separately by the actual position of the flaps and slats. If the slats are still in transit above 230 , the aural/ECAM warning will trigger until the system has registered that they are retracted fully.
When using the autoflap retract procedure, the buffer between a selected speed of 220kts and VFE CONF 1 (230) can sometimes not be sufficient if there is a delay after engaging managed speed before CONF 0 is selected. So, select CONF 0 & pause before pushing managed speed (250).
When using the autoflap retract procedure, the buffer between a selected speed of 220kts and VFE CONF 1 (230) can sometimes not be sufficient if there is a delay after engaging managed speed before CONF 0 is selected. So, select CONF 0 & pause before pushing managed speed (250).
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A320 Flap overspeed during retraction?
Thank you guys for your kind replies.
The point what we try to be clear is whether he committed flap overspd even though he engage flap 0 at 's' spd.
At that situation, he had to level off at 3000' he ordered to f/o to set flaps '0' at just passing s spd during acceleration.(it was around 205kts)
During flap transit, the checker saw spd trend passing 230 kts even the flap indication still showing blue.(after QAR review we found out spd was 235kts when actually flap finished its movement to 0)
Anyway.. He ordered "flaps 0" just passing s spd. Does he still have to be blamed because he didn't pull spd below 230kts?
The point what we try to be clear is whether he committed flap overspd even though he engage flap 0 at 's' spd.
At that situation, he had to level off at 3000' he ordered to f/o to set flaps '0' at just passing s spd during acceleration.(it was around 205kts)
During flap transit, the checker saw spd trend passing 230 kts even the flap indication still showing blue.(after QAR review we found out spd was 235kts when actually flap finished its movement to 0)
Anyway.. He ordered "flaps 0" just passing s spd. Does he still have to be blamed because he didn't pull spd below 230kts?
Last edited by FlywithPark; 24th Jun 2013 at 01:17.
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Lucky guy and A4
Don't worry about that nice man. There is an Airbus presentation on this subject. What I stated is from that. Any speed above Vls is safe but if you fly at Vls in turbulence for long time it can trigger alfa floor during maneuvring. 230kts is flap1 lowering speed. S is the speed at which with +ve trend you retract. I have not said anything about alfa lock I am talking about alpfa floor. If you fly below GD it may trigger at 40 degrees of bank. On AP AC does not bank that much anyway. Have buffer by all means if you have but surely don't bust flaps for that. As long as you retract at S speed accelerating going clean below green dot is not forbidden.
Don't worry about that nice man. There is an Airbus presentation on this subject. What I stated is from that. Any speed above Vls is safe but if you fly at Vls in turbulence for long time it can trigger alfa floor during maneuvring. 230kts is flap1 lowering speed. S is the speed at which with +ve trend you retract. I have not said anything about alfa lock I am talking about alpfa floor. If you fly below GD it may trigger at 40 degrees of bank. On AP AC does not bank that much anyway. Have buffer by all means if you have but surely don't bust flaps for that. As long as you retract at S speed accelerating going clean below green dot is not forbidden.
Last edited by vilas; 23rd Jun 2013 at 15:01.
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FlywithPark
Only now you stated the real problem that is he had to level off. Climbing acceleration is not a problem. Whenever you don't want acceleration the remedy is to pull speed and then solve the problem. Since he didn't do that it is overspeed. It can happen only at high weights in level flight. Normal weights the higher margin will take care. Bad luck it was a check ride.
Only now you stated the real problem that is he had to level off. Climbing acceleration is not a problem. Whenever you don't want acceleration the remedy is to pull speed and then solve the problem. Since he didn't do that it is overspeed. It can happen only at high weights in level flight. Normal weights the higher margin will take care. Bad luck it was a check ride.
Ut Sementem Feeceris
MD,
The autothrust will protect against overspeed if configured i.e. limit speed to VFE Next.......but when you select FLAP 0, there is no VFE Next so the autothrust will keep the thrust on to target 250 knots and,if level, easily out accelerate the SLAT retract with resulting overspeed.
The autothrust will protect against overspeed if configured i.e. limit speed to VFE Next.......but when you select FLAP 0, there is no VFE Next so the autothrust will keep the thrust on to target 250 knots and,if level, easily out accelerate the SLAT retract with resulting overspeed.
Last edited by A4; 23rd Jun 2013 at 15:18.
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FlywithPark, A4 and Luckyguy
What I could copy from Airbus document is below.
In CONF1+F:S speed could be close to VFE
IfFLAPS 0 selected above Flap auto retraction speed (210 Kts on this example):
PossibleVFE OVERSPEED warning if rapid aircraft acceleration
NoVFE structural limit exceedance.
Do not delay FLAPS 0 selection above S speed =>prevents possible momentary VFE OVERSPEED warning
Flap maneuvering speeds are not limitations:
Itis safe to fly between VLS and VMAX (VMO, VLE, VFE) :
The requiredaerodynamic margin is properly ensured
This is from Airbus. I hope this answers all doubts.
What I could copy from Airbus document is below.
In CONF1+F:S speed could be close to VFE
IfFLAPS 0 selected above Flap auto retraction speed (210 Kts on this example):
PossibleVFE OVERSPEED warning if rapid aircraft acceleration
NoVFE structural limit exceedance.
Do not delay FLAPS 0 selection above S speed =>prevents possible momentary VFE OVERSPEED warning
Flap maneuvering speeds are not limitations:
Itis safe to fly between VLS and VMAX (VMO, VLE, VFE) :
The requiredaerodynamic margin is properly ensured
This is from Airbus. I hope this answers all doubts.
Last edited by vilas; 23rd Jun 2013 at 16:18.