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Not extending flaps while gear is extending

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Not extending flaps while gear is extending

Old 8th Feb 2019, 05:51
  #21 (permalink)  
 
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Manufacturer's procedures are sort of optimum covering all situations. Extending gear and flaps together is to avoid overloading the hydraulic systems involved. It's not forbidden or a limitation but a matter of good operating practice. Company procedure Gear down Flap3 may not necessarily be to overrule Airbus and a must do this way. Could easily be a case of hasty adaptation.
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Old 8th Feb 2019, 07:31
  #22 (permalink)  
 
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Originally Posted by giggitygiggity View Post
Precisely, if it was a limitation, it would be in the FCOM-LIM. Years ago I remember a good captain denying me flaps 3 whilst the gear was travelling (after admittedly I forgot to configure in time). We finally selected flaps full out at about 1020ft (so 20ft away from our approach gate) to satisfy his limitation. People get so caught up in this crap that they totally miss the big picture. He would have probably rather have executed a go-around than 'stressing' the hydraulics .

so you “forgot to configure in time” and the captain is the one not seeing the big picture... ok
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Old 8th Feb 2019, 08:37
  #23 (permalink)  
 
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It is a PTU limitation and the procedure is there to cover single engine case. When in single engine the PTU is transferring HYD power from one system to another. The pressure transmitted by the PTU is 2500 PSI, not 3000 as the EDP, so the PTU is not capable of handling both gear and flaps at the same time. Following Airbus philosophy of designing procedures that are easy to remember and to follow, they decided that it would be better if they implement the rule of not operating gear and flaps at the same time in ALL situations, anticipating the fact that most pilots would forget about this in the quite infrequent case of single engine approach and landing.

The PTU limitation USED to be in the FCOM loooooooong time ago (like so many more things!), but got removed a while ago.
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Old 8th Feb 2019, 09:42
  #24 (permalink)  
 
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Air Berlin had a procedure to select the gear down lastest 6 NM out, and then wait for the speed to drop way down, until about 15 kt over Vapp, only then select flaps 3.
Apparently it reduces the wear on the flaps (aerodynamic loading) quite a bit.
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Old 8th Feb 2019, 09:52
  #25 (permalink)  
 
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Check Airman, that sounds like the Boeingization of Airbus procedures. There is no other reason for linking GD with F3.
It is. My company used the vanilla Airbus SOPs until we were bought by another which had both types and where the Boeing fleet was the legacy fleet and had primacy. Now we have had to go back to Airbus SOPs, selecting flap 3 after the gear is down is back in - although I do seem to fly with a number of pilots who haven't noticed. And there is a good reason for it. Airbus don't want the hydraulic systems overloaded as hydraulic pressure is used to both raise and lower the gear. Boeings on the other hand use gravity to lower the gear and the weight of the gear pushing the fluid out of the jack actually increases hydraulic system performance.
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Old 8th Feb 2019, 10:02
  #26 (permalink)  
 
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Boeings on the other hand use gravity to lower the gear and the weight of the gear pushing the fluid out of the jack actually increases hydraulic system performance.
Do you want to reconsider?
The gravity assisted gear will be pushing fluid into the return line to the Hyd reservoir. It can't assist system performance.
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Old 8th Feb 2019, 14:48
  #27 (permalink)  
 
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Originally Posted by iggy View Post
It is a PTU limitation and the procedure is there to cover single engine case. When in single engine the PTU is transferring HYD power from one system to another. The pressure transmitted by the PTU is 2500 PSI, not 3000 as the EDP, so the PTU is not capable of handling both gear and flaps at the same time. Following Airbus philosophy of designing procedures that are easy to remember and to follow, they decided that it would be better if they implement the rule of not operating gear and flaps at the same time in ALL situations, anticipating the fact that most pilots would forget about this in the quite infrequent case of single engine approach and landing.

The PTU limitation USED to be in the FCOM loooooooong time ago (like so many more things!), but got removed a while ago.
Hadn't considered the single engine case. Same profile in the simulator though, and no issues. I ASSUME the sim modelling is right.

If it used to be in the FCOM, it leads me to believe that it's probably an issue with older planes.
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Old 8th Feb 2019, 14:54
  #28 (permalink)  
 
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Originally Posted by InSoMnIaC View Post



so you “forgot to configure in time” and the captain is the one not seeing the big picture... ok
I agree with giggitygiggity .

The captain lost the big picture. Mistakes happen, people fall behind, situations deviate from the ideal world of the SOP. A pilot must be able to quickly and safely adapt to a changing situation.

If they weren't stable until 1020ft, I'd say piss poor aviating and leadership on the part of the captain.
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Old 8th Feb 2019, 15:56
  #29 (permalink)  

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It is not your best day when you foul up the other pilot's intention by sticking to the letters verbatim. Still a moment to learn from.

1000 ft of RA, AFE, above TDZ elev? Either way 1020 is above that. Then the hamsterwheel IMC/VMC, the latter having different legal definitions based on the airspace class etc.

BTW the Airbus' own FDM/QAR algorithms flag the CONF only at 750 ft ATDZ. And FCOM has no criteria of speed in the stable approach paragraph (both for a reason).



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Old 8th Feb 2019, 16:32
  #30 (permalink)  
 
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Originally Posted by FlightDetent View Post
It is not your best day when you foul up the other pilot's intention by sticking to the letters verbatim. Still a moment to learn from.

1000 ft of RA, AFE, above TDZ elev? Either way 1020 is above that. Then the hamsterwheel IMC/VMC, the latter having different legal definitions based on the airspace class etc.

BTW the Airbus' own FDM/QAR algorithms flag the CONF only at 750 ft ATDZ. And FCOM has no criteria of speed in the stable approach paragraph (both for a reason).
Agreed 100% that it's a learning moment, but you adapt and go, and talk about it afterwards. Being pedantic for the sake of it does not achieve anything. If we're going to fault the FO for admitting that he got distracted and configured too late, the captain should also be faulted for not effectively monitoring, and catching the error earlier.
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Old 8th Feb 2019, 18:16
  #31 (permalink)  
 
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If it used to be in the FCOM, it leads me to believe that it's probably an issue with older planes.
why the note was removed is difficult to guess but what matters is that the procedure " When flaps are at two gear down. When gear is down flap three" still remains in place. So there's some logic. If someone did something different to save a situation it can only be as an exception.
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Old 8th Feb 2019, 23:28
  #32 (permalink)  
 
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Vilas, I agree the perfect approach would have us fly the "When flaps are at two gear down. When gear is down flap three" procedure. But we know the real world is not like that, either through omission (as above) or ATC demands.

But does your A320 FCOM have the note in italics about extending the gear after Flap 2 to reduce speed as I mentioned above? Before the "When Flaps are at 2" procedure?
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Old 9th Feb 2019, 03:18
  #33 (permalink)  
 
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Italics off course are mine. But it's in bold letters. And we had the same procedure in A300 and A310 or in B747 for that matter.
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Old 9th Feb 2019, 05:05
  #34 (permalink)  
 
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compressor stall. Even QRH says the same thing.

•When FLAPS 2:
L/G DOWN........................................................ ORDER L/G.......................................................SELE CT DOWN
AUTO BRAKE.....................................CONFIRM
GRND SPLRS.......................................... ARM
EXTERIOR LIGHTS...................................................... SET
•When L/G down:
FLAPS 3....................................ORDER
FLAPS 3........................................................... ................. SELECT
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Old 9th Feb 2019, 07:05
  #35 (permalink)  
 
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Originally Posted by Check Airman View Post
I agree with giggitygiggity .

The captain lost the big picture. Mistakes happen, people fall behind, situations deviate from the ideal world of the SOP. A pilot must be able to quickly and safely adapt to a changing situation.

If they weren't stable until 1020ft, I'd say piss poor aviating and leadership on the part of the captain.
Maybe he was trying to teach the FO a lesson he would never forget. Although admittedly cutting it tight, they were stable by 1000'. Whats so piss poor about that?
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Old 9th Feb 2019, 15:28
  #36 (permalink)  
 
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Originally Posted by InSoMnIaC View Post
Maybe he was trying to teach the FO a lesson he would never forget. Although admittedly cutting it tight, they were stable by 1000'. Whats so piss poor about that?
I say poor aviating and leadership because by deliberately delaying configuration, the FO probably got unduly stressed, possibly focussing on speed, to the detriment of other instruments. Probably causing temporary tunnel vision. Reduced SA for both of them, as they're now closely watching the altimeter, counting the inches, down to 1000ft.

If he'd configured the airplane as requested, they'd have been stable earlier without the anxiety and extra crm related tension.
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Old 9th Feb 2019, 19:32
  #37 (permalink)  
 
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To play Devil's Advocate, it does say "when flap two, select gear down". Do you always immediately do this, or wait for a more suitable time?
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Old 9th Feb 2019, 21:12
  #38 (permalink)  
 
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I'm thinking if we don't separate gear and flaps during a G/A, then it isn't an issue on the approach. The big hydraulic demand is when the gear is raised... [pure comment on technical suitability of combining both actions, not the SOP's - I hear ya Villas!]
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Old 9th Feb 2019, 22:21
  #39 (permalink)  

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Cough keep in mind the aero forces on the flaps have different effect whether you are retracting or extending. Another point to consider, during GA there is no simultaneous movement of flaps and L/G. Not even of L/G doors (which are dropping down anyways).

madcow1 read that in the context of the full sequence: F2 at 2000 ft AAL. Delaying the L/G call afterwards is not really an option to meet the stabilization criteria. Moreover, F2 initially create a small speed increment and speed reduction is debatable. Only taking the gear out without delay slows you down, which helps to reduce loads on flap mechnanism more quickly.

Notwithstanding the fact that on airports where 180/160 speed control is applied, following the Airbus decelerated SOP is not a workable option.

Last edited by FlightDetent; 10th Feb 2019 at 07:02.
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Old 10th Feb 2019, 03:15
  #40 (permalink)  
 
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Cough
I'm thinking if we don't separate gear and flaps during a G/A, then it isn't an issue on the approach.
. Purely from go around perspective, we do and should separate gear and flaps. The flap is retracted from full to 3. Then FMA(which ensures TOGA&SRS) and sustained climb only then gear up. That's the lesson driven home by Dubai 777 accident. If the gear wasn't retracted it wouldn't have happened.
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