Flap extension before clear signal from ground crew?

[CaptLeslie]

Many airlines extend flaps before they start taxiing. Some airlines have a procedure that requires them to wait with flaps extension until clear signal is given by the ground crew. Can any of you guys expand a bit on this? Why can't the crew extend flaps anytime after engine start without waiting for clear signal? Are there any routine situations where there may be equipment under the wing after engine start?

 

[PurpleTail]

IMO, it is always what is safest.

Until everyone is out of harms ways your complete attention needs to be on the 'all clear' signal before doing anything. Too many things have happened before the tow bar gets disconnected, espially when hydraulics systems are involved operating at 3000 psi.

I believe there a couple shcools of thought on configuring the aircraft and taxiing, ie. runway and taxi incursions are on the rise and the FAA is trying to reverse that trend. The more sets of eyes you have looking outside the better so some companies configure for takeoff before taxi while others do it while they are taxiing.

 

[radarlove]

You didn't answer the question. What possible harm could flap extension cause after a push-back? 3,000 psi or not, what's the rationale behind it? The "safest" thing for us to do is to stay in bed in the morning.

 

[ptarmigan]

Too many variables to answer the question. What type aircraft, what facilities are present, etc, etc? There are some aircraft/operators that extend flaps and have ground crew check them prior to taxi, others that don't configure until much later for other reasons, etc. Yes, ground equipment can be a consideration. I am not aware of anyone that extends them prior to engine start or during pushback. Use your imagination on what sorts of reasons that might be, it's not too hard!

 

[Gorilla]

At AA in the 737, not sure about other fleets, we are lowering flaps during pushback with the electric pumps. It is a change from previous days when they would be lowered during taxi.

IMO and most others it is not the smartest thing to do for the reasons stated. It doesn't save any time. If we (AA) want to make the taxi out simpler and faster, the mechanical checklist needs trimming. We have two occurrences of TRANSPONDER, T/O BRIEF, and probably others, once on before starting engines checklist, another while taxiing. It's stupid. How many times do we need to brief T/O on a clear day, or check that the transponder is set?

 

[geshields]

At CAL, we lower the flaps after engine start/pushback and after the all clear is given. Rationale is that you never know if a late bag is coming, etc. And some of the rampers may not be paying attention to the flaps coming down while the baggage cart is sitting underneath them....

They are also lowered prior to taxi so the F/O can be heads up while the CA is taxiing and help him/her out. No checklists are done while taxiing.

Initially I thought this was a weird, but after doing it a while and catching some taxi errors it is a great idea. The procedure is standard to our whole fleet which I also think is a great idea.

 

[milplt]

When you are moving under your own power, you can rest assured that there is nothing beneath the wings. But in a ramp area, there is no telling where the GPU, huffer cart, fuel truck, etc. may have just been parked. I have seen a picture of a DC-10 whose flaps were lowered onto AGE - quite a bit of damage. Nothing wrong with using the extra set of eyes.

 

[Rez O. Lewshun]

What's the rush?

 

[Gorilla]

They are also lowered prior to taxi so the F/O can be heads up while the CA is taxiing and help him/her out. No checklists are done while taxiing.

Seriously? Isn't there a formalized T/O data/bugs check during taxi, at a minimum? What if you get a runway change, or the SID is altered? Ideally we should minimize checklist crap during taxi, but some of it seems inevitable.

AA is the king of huge checklists; lot of good it has done us the last decade.

 

[geshields]

Seriously? Isn't there a formalized T/O data/bugs check during taxi, at a minimum? What if you get a runway change, or the SID is altered? Ideally we should minimize checklist crap during taxi, but some of it seems inevitable.

AA is the king of huge checklists; lot of good it has done us the last decade.

T/O speeds are set as soon as we get the W & B (prior to push). They are verified during the after start check (prior to taxi)...

Runway change or SID change are the exception, then the f/o is typing in the box...

 

[Patriot328]

Seriously? Isn't there a formalized T/O data/bugs check during taxi, at a minimum? What if you get a runway change, or the SID is altered? Ideally we should minimize checklist crap during taxi, but some of it seems inevitable.

AA is the king of huge checklists; lot of good it has done us the last decade.

to expand on geshields' answer, our Before T/O also has a departure brief where we can change or verify what we're about to do (ie, review transition altitude if it's not 18k or review new sid/rwy if it's been given to us during taxi) and also verify the flaps one more time, along with T/O config. Works out well.

 

[Buzzard]

The 747-200 and -100 had the flap indicator in the actuator not at the actual physical flap setting. A 747 years ago took off with T/O flaps indicated, but the flaps were physically up. They crashed, new procedure, ground verifies actual flap extension. Not sure about the -300 and 400. Also some airlines have had near accidents by rushing to T/O, they instituted a procedure to not taxi until T/O flaps verified. Its common prudence to not move any flight controls or flaps until all clear from marshaller.

 

[Mgmt1Pilot]

to expand on geshields' answer, our Before T/O also has a departure brief where we can change or verify what we're about to do (ie, review transition altitude if it's not 18k or review new sid/rwy if it's been given to us during taxi) and also verify the flaps one more time, along with T/O config. Works out well.

Our current checklist has the departure brief while taxing out. If their is a problem with eyes not being outside the cockpit its during this brief. We are now going to be required to perform a departure brief while still at the gate prior to push. If a revision is necessary we will do that during taxi out ( doesn't happen often ). Flaps are after engine start, either one engine or two, at the Capt discretion. He be the boss :=)

 

[aa73]

Problem with AA''s Before T/O checklists is this: The CA answers to EVERYTHING on the list.

At most other airlines, the CA only answers to a couple of imprtant items, all other items are asked AND answered/verified by the F/O, out loud. At AA the CA has to even answer to "Transponder", "Exterior Lights", "Ignition", etc. Too much talking from the guy in the left seat.

We definitely need to simplify.

73