A320 Flap overspeed during retraction?
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
Likes: 0
Received 0 Likes
on
0 Posts
"How about preselecting 215 kts in Perf CLB page and once flaps+slats retracted confirmed on E/WD, go managed speed? "
A tad Magenta.
Also, would you not then be stuck at 215 kts for the climb? - well, at least until > FL100, if in managed then I assume it would default to - -whatever your managed speed for the climb was - say, 270.
A tad Magenta.
Also, would you not then be stuck at 215 kts for the climb? - well, at least until > FL100, if in managed then I assume it would default to - -whatever your managed speed for the climb was - say, 270.
Last edited by Natstrackalpha; 28th May 2014 at 22:20.
Join Date: Apr 2013
Location: everywhere
Posts: 128
Likes: 0
Received 0 Likes
on
0 Posts
Now your procedures tells you that it is not allowed to fly clean below green dot speed. How do you fix that problem now?
Keep it simple!
Join Date: Sep 2001
Location: Third planet from the sun
Posts: 383
Likes: 0
Received 0 Likes
on
0 Posts
The case of temporary overspeed aural warning during slats / flaps retraction after a heavy-weight take-off
In the particular case of a heavyweight take-off, the risk of a temporary overspeed aural warning is increased. Indeed, in this configuration, S speed is quite close to VFE CONF 1+F because the aircraft weight is higher and the lift needed to climb is higher too. Therefore the slats need to remain extended for longer. As a result, the crew will order flaps retraction at a speed that might be higher than the Flaps Auto-retraction speed.
In that case, should the acceleration of the airplane be rapid, a VFE aural warning may momentarily trigger.
This logic is as per design and structural limits are not encountered.
For example, an A320 at a Take-Off Weight (TOW) of 76T, S speed of 205 kts, the pilot will order flaps retraction most probably at or slightly above
210 kts, which is precisely the Flaps Auto-retraction speed. Once the slats / flaps control lever is in the retracted position, the VFEred and black strip is no longer displayed on the PFD speed scale. If the airplane accelerates rapidly, then the airspeed may catch up the actual instantaneous VFE momentarily, which will trigger the VFE aural warning.
Again, this logic is as per design and structural limits are not encountered.
Source: Airbus Safety First Magazine 20. Page 12
In the particular case of a heavyweight take-off, the risk of a temporary overspeed aural warning is increased. Indeed, in this configuration, S speed is quite close to VFE CONF 1+F because the aircraft weight is higher and the lift needed to climb is higher too. Therefore the slats need to remain extended for longer. As a result, the crew will order flaps retraction at a speed that might be higher than the Flaps Auto-retraction speed.
In that case, should the acceleration of the airplane be rapid, a VFE aural warning may momentarily trigger.
This logic is as per design and structural limits are not encountered.
For example, an A320 at a Take-Off Weight (TOW) of 76T, S speed of 205 kts, the pilot will order flaps retraction most probably at or slightly above
210 kts, which is precisely the Flaps Auto-retraction speed. Once the slats / flaps control lever is in the retracted position, the VFEred and black strip is no longer displayed on the PFD speed scale. If the airplane accelerates rapidly, then the airspeed may catch up the actual instantaneous VFE momentarily, which will trigger the VFE aural warning.
Again, this logic is as per design and structural limits are not encountered.
Source: Airbus Safety First Magazine 20. Page 12
Be careful if departing at high weights with an MEL item indicating flaps/slats slow. Under normal circumstances the lift devices would retract before you accelerated through their limiting speeds, however if clean speed is high due to an increase in weight its quite easy to be passing 215/230kts while they're still on the way in. In this situation select minimum clean speed and wait until retraction is completed before managing the speed.
If departing in the mid 70t range I brief to expect a possible auto retract of the flaps as it only takes a little turbulence or even a turn to trigger it. Flaps go up and barbers pole moves up no drama, though it is recorded by FDM. The reason is obvious in the case of a high weight T/O though at lower weights you may be asked for an explanation.
Auto retract is the reason some MEL items prohibit T/O in 1+F incase it gets triggered at an inappropriate time. There is no auto retract in CONFIG 2 or 3.
If departing in the mid 70t range I brief to expect a possible auto retract of the flaps as it only takes a little turbulence or even a turn to trigger it. Flaps go up and barbers pole moves up no drama, though it is recorded by FDM. The reason is obvious in the case of a high weight T/O though at lower weights you may be asked for an explanation.
Auto retract is the reason some MEL items prohibit T/O in 1+F incase it gets triggered at an inappropriate time. There is no auto retract in CONFIG 2 or 3.
Join Date: Mar 2004
Location: Europe
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
It's also good to note, that even without FLAPS/SLATS SLOW - indication, they don't always retract at the same rate. I've witnessed almost twice as slow retraction of flaps on at least one aircraft one day, during several sectors. The difference was there also when retracting on the ground (I timed it for comparison to other aircraft).
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
Likes: 0
Received 0 Likes
on
0 Posts
I think they were being picky. Sometimes they want you to do a F3 departure, in the box, just to see if you get all the flaps up in time to avoid a flap limiting . . . thing.
Join Date: Mar 2001
Location: I wouldn't know.
Posts: 4,497
Likes: 0
Received 0 Likes
on
0 Posts
A tad Magenta.
Also, would you not then be stuck at 215 kts for the climb? - well, at least until > FL100, if in managed then I assume it would default to - -whatever your managed speed for the climb was - say, 270.
Also, would you not then be stuck at 215 kts for the climb? - well, at least until > FL100, if in managed then I assume it would default to - -whatever your managed speed for the climb was - say, 270.
Join Date: Mar 2009
Location: Roaming
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
This is mentioned in one of the safety first magazine issued by Airbus
If it helps
On A300/A310, A320 and A330/ A340 Families,
• The VFE value displayed on the PFD
is based on the slats / flaps con- trol lever position and it moves by one step as soon as this lever is moved.
• The overspeed aural warning trig- gering threshold varies according to the actual aircraft configuration, i.e. the slats / flaps surfaces real time position.
Therefore, during slats / flaps tran- sition, the dynamic acceleration of the airplane may lead to a temporary OVERSPEED WARNING even if the current speed is out of the red and black strip displayed on the PFD. In this situation, there are neither opera- tional consequences nor safety issues.[
If it helps
On A300/A310, A320 and A330/ A340 Families,
• The VFE value displayed on the PFD
is based on the slats / flaps con- trol lever position and it moves by one step as soon as this lever is moved.
• The overspeed aural warning trig- gering threshold varies according to the actual aircraft configuration, i.e. the slats / flaps surfaces real time position.
Therefore, during slats / flaps tran- sition, the dynamic acceleration of the airplane may lead to a temporary OVERSPEED WARNING even if the current speed is out of the red and black strip displayed on the PFD. In this situation, there are neither opera- tional consequences nor safety issues.[
