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Setting Flaps For Takeoff While Taxiing?  
User currently offlineJfrworld From United States of America, joined Aug 2004, 365 posts, RR: 0
Posted (7 years 8 months 2 weeks 6 days 9 hours ago) and read 5935 times:

OK - I'll admit that my question may be a bit odd, but who decides when a pilot should set the flaps into takeoff position? Is this pilot preference or airline operating procedure.

I fly UA, WN, and US(HP) the most of all the US dometics. I always assumed having flown WN and HP for most of my life that the pilot is supposed to set the flaps just after the plane has been pushed back from the gate, but before the plane begins taxiing to the runway for takeoff (before the plane has begun moving under its own engine power). I never noticed anything different until a UA flight about 6 months ago. We were flying PHX-SFO and after we pushed back, the pilot began taxing without the flaps set. We taxied almost to the end of the runway before the pilot actually set the flaps (I was starting to sweat at this point as I thought the pilot had forgotten). I've flown UA twice and HP twice since then and I notice the same pattern. The UA pilots set the flaps during taxi and the HP pilots set the flaps just after pushback, but before taxi. Does anyone have any opinions on this?

64 replies: All unread, showing first 25:
 
User currently offlineJeffry747 From United States of America, joined Jun 2005, 963 posts, RR: 2
Reply 1, posted (7 years 8 months 2 weeks 6 days 9 hours ago) and read 5922 times:
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If I remember correctly the pilots will start running through the pre-flight checklist immediately after pushback. They will set the flaps when it comes up on the list.


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User currently offlineTristarsteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 2, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5901 times:

On BA it is mandatory to set the flaps after engine start and before taxi. You must set the flaps before you release the brakes.

User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 3, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5897 times:

Quoting Tristarsteve (Reply 2):
On BA it is mandatory to set the flaps after engine start and before taxi. You must set the flaps before you release the brakes.

I know one, maybe two US airlines where you may NOT operate the flaps while in a congested area such as the ramp. Personnel safety is the reason.

Last I seem to recall without looking in my manual is as soon as we began taxiing. Tug disconnects, safety guy pulls his headset plug, first officer gets taxi clearance and captain takes he pushback crew salute and we are off. First officer sets takeoff flaps and maybe drives the stab trim to the proper setting.

One reason for not setting them while the tug is still attached is because you might not have the final flap setting yet.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineJfrworld From United States of America, joined Aug 2004, 365 posts, RR: 0
Reply 4, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5891 times:

Quoting Tristarsteve (Reply 2):
On BA it is mandatory to set the flaps after engine start and before taxi. You must set the flaps before you release the brakes.

Based on my experiences on WN and HP, I assumed this to be true in all cases. It was only after I was paying attention on UA during the last year did I notice that it doesn't appear to always be the case.

Personally, it makes sense to set the flaps before you release the brakes for taxi. It seems as though you would be less likely to forget this way.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 5, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5879 times:

Quoting Jfrworld (Reply 4):

Personally, it makes sense to set the flaps before you release the brakes for taxi. It seems as though you would be less likely to forget this way.

One would hope the checklists would take care of it whenever it is done  Wink



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline777236ER From , joined Dec 1969, posts, RR:
Reply 6, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5875 times:

If the flaps aren't set by the crew, and there's no memory procedure to follow when turning onto the runway, then you're putting the fate of the aircraft on the configuration warning. It's a system that has failed before and will fail again. There aren't enough redundancies built into the system to justify letting the crew set and crosscheck flaps during the taxi.

Delta 1141 is one crash that springs to mind. I'm sure there are others.


User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 7, posted (7 years 8 months 2 weeks 6 days 8 hours ago) and read 5866 times:

Should also mention that there can be aircraft system-specific reasons for waiting. If for example the flaps were in transit when the electrical system switches over from APU to engine-driven or from the secondary EDG to the primary it is conceivable that it could fault the flap control system. Ever notice the safety video losing it during the generator changeover?

Not saying it always would, but I could beleive it might, on some aircraft.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineBoeingFixer From Canada, joined Jul 2005, 525 posts, RR: 0
Reply 8, posted (7 years 8 months 2 weeks 6 days 6 hours ago) and read 5837 times:

Quoting 777236ER (Reply 6):
There aren't enough redundancies built into the system to justify letting the crew set and crosscheck flaps during the taxi.

In this day and age of human factors training your above quote makes it appear that those in aviation haven't learned anything from past errors.

It makes no difference whether takeoff flaps are set before or during taxi as long as the checklists are followed. Company SOP's usually dictate when the appropriate check lists are to be carried out. Our SOP is to set takeoff flaps after pushback and the taxi has started.

Cheers,

John



Cheers, John YYC
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 9, posted (7 years 8 months 2 weeks 6 days 6 hours ago) and read 5834 times:

Quoting 777236ER (Reply 6):
If the flaps aren't set by the crew, and there's no memory procedure to follow when turning onto the runway, then you're putting the fate of the aircraft on the configuration warning.

You have a good point. But there's really no memory procedure for setting them at pushback either. It's all checklists. Or am I barking up the wrong tree?



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently onlineLimaFoxTango From Antigua and Barbuda, joined Jun 2004, 771 posts, RR: 1
Reply 10, posted (7 years 8 months 2 weeks 6 days 6 hours ago) and read 5827 times:

I think in the after start checklist or taxi checks for most airliners mentions flaps somewhere. Also, I dont think its possible for most, if not all commercial aircraft to take off flapless or a takeoff configuration warning horn will sound once the throttles are moved above a certain preset setting.


You are said to be a good pilot when your take-off's equal your landings.
User currently offlineModesto2 From United States of America, joined Jul 2000, 2769 posts, RR: 6
Reply 11, posted (7 years 8 months 2 weeks 6 days 6 hours ago) and read 5821 times:

This is an interesting question - one that I always wondered. Hope this helps...

My company policy is to drop the flaps when doing the taxi checklist. And we do the taxi checklist when BOTH engines are running. So, if we push and start both engines, then I'll drop the flaps after both engines are running. That may be before we start rolling or as we start rolling away from the ramp. If it's a one-engine taxi to save fuel, then I drop the flaps after the second engine has been started. That may be just a few minutes before takeoff. As others have stated, we avoid extending the flaps in the ramp area (i.e. during pushback) to ensure adequate clearance from ramp equipment.


User currently offlineAJ From Australia, joined Nov 1999, 2381 posts, RR: 24
Reply 12, posted (7 years 8 months 2 weeks 6 days 6 hours ago) and read 5822 times:

We have just switched to Boeing SOP on the 737/744/767 fleets which calls for the flaps to be set immediately before the 'Before Taxi' checklist.

User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 13, posted (7 years 8 months 2 weeks 6 days 3 hours ago) and read 5760 times:

On the B737s out here Company SOP states to Extend LEDs & Confirm with Ground Mx, during Engine Start & Prior to Taxi.
On the B757s Ground Mx does not confirm & the Pilots extend LEDs only after Taxi according to their Checklist.

regds
MEL



Think of the brighter side!
User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 14, posted (7 years 8 months 2 weeks 6 days 1 hour ago) and read 5745 times:

It depends on the airline...some airlines don't have a taxi checklist, some do. As long as the items get done, and the checklist is approved by the FAA, then each airline can do things in the order they see fit.

User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2254 posts, RR: 16
Reply 15, posted (7 years 8 months 2 weeks 6 days 1 hour ago) and read 5736 times:

Quoting SlamClick (Reply 3):
I know one, maybe two US airlines where you may NOT operate the flaps while in a congested area such as the ramp. Personnel safety is the reason.

This our policy and there is no checklist done when crossing a runway. The capt will give the command "cleared to configure" and all items are done then the checklist is read to confirm all actions complete


User currently offlinePeterPuck From Canada, joined Jun 2004, 318 posts, RR: 3
Reply 16, posted (7 years 8 months 2 weeks 6 days ago) and read 5727 times:

We set flaps when clear of the congested ramp area. Other possible reasons for late flap extension might be contaminated taxiways (slush), or de-icing procedures.

User currently offlineWILCO737 From Greenland, joined Jun 2004, 8898 posts, RR: 76
Reply 17, posted (7 years 8 months 2 weeks 6 days ago) and read 5719 times:
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HEAD MODERATOR

Hey there,

we on LH (737 and 320) fleet we set the flaps and perform the flight control check right after the engines has stabilized at idle, together with the rest of the after start items! Then the after start checklist and then we start taxiing...

WILCO737
 airplane 



It it's not Boeing, I am not going.
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 18, posted (7 years 8 months 2 weeks 6 days ago) and read 5715 times:

As many can clearly notice, many variations with specific airline operating procedures.
The last post mentioned contaminated taxiways, ice, snow, etc.
On some aircraft (the B707 comes to mind) the flaps were absolutely NOT moved from the fully retracted position when in these winter conditions, until the airplane was at the end of the taxiway, and in a position to move onto the active runway...and for very good reasons.
Ice and compacted snow on the flaps?
Yes.
Also, the balance bays were more exposed during the period when the flaps were extended, and ice/snow in these areas was very bad news.

The simple answer is...

The flaps are extended when the Commander says they will be extended, and not before.
After the specific taxi items are completed, the taxi checklist is then completed.

So called 'memory' does not enter into the picture.
Set the specific items.
Then call for the specific checklist.

Oh yes, the Commander calls for the checklist, and it is read by either the First Officer or the Flight Engineer, as appropriate, with all airlines that I have worked for.

It ain't a guessing game, you follow the specific airline procedure.
Period.


User currently offlineCanyonblue737 From United States of America, joined Aug 2006, 29 posts, RR: 0
Reply 19, posted (7 years 8 months 2 weeks 5 days 4 hours ago) and read 5525 times:

A significant safety related item, such as setting flaps for takeoff is ALWAYS dictated by company SOP (standing operating procedure.) What you were seeing is variations between companies, and the fact all the UA pilots set it while in motion while the WN pilots did it before taxi indicates all were following their particular companies SOP. It is becoming more common in the industry to set flaps prior to taxi, in fact to do almost all required checks prior to taxi (to allow pilots to focus on where they are going) but obviously there are still tons of variations on how to fly an airplane.

All are safe, and everything you saw was normal and standard. Also remember all airliner aircraft have systems to warn pilots that they didn't set the flaps properly if they attempt to takeoff without them.


User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 20, posted (7 years 8 months 2 weeks 5 days 1 hour ago) and read 5497 times:

Quoting Canyonblue737 (Reply 19):
A significant safety related item, such as setting flaps for takeoff is ALWAYS dictated by company SOP (standing operating procedure.)

Is there something that can be excluded from being a significant safety item? What is a significant safety item? Could be a multitude of things; even the security/power up check can have huge safety impacts. If a company wants to set flaps with the receiving checklist, and that is approved in the opspecs (via the FAA) then that becomes the procedure.

Please read what others have written to avoid duplication.


User currently offlineSpeedracer1407 From United States of America, joined Dec 2004, 333 posts, RR: 0
Reply 21, posted (7 years 8 months 2 weeks 5 days 1 hour ago) and read 5490 times:

Quoting SlamClick (Reply 3):
I know one, maybe two US airlines where you may NOT operate the flaps while in a congested area such as the ramp. Personnel safety is the reason.

A couple questions about that:

First, if takeoff flap settings don't deploy the flaps very far down, do they really pose a danger to ground personnel? As a passenger, it seems like takeoff flaps extend a few inches, and droop a few inches. Nothing more.

Second, since flaps are set, presumably, with at least one engine running, or at least near startup, who's gonna be hanging out near the trailing edge of the wing?



Dassault Mercure: the plane that has Boeing and Airbus shaking in their boots.
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 22, posted (7 years 8 months 2 weeks 4 days 22 hours ago) and read 5463 times:

Out here the Explanation given for LED extension on Engine Start up for B737 was for Ground Mx Crew Confirmation that they are Properly Extended.This is in addition to the P5 Overhead display available on P5.
regds
MEL



Think of the brighter side!
User currently offlineCanyonblue737 From United States of America, joined Aug 2006, 29 posts, RR: 0
Reply 23, posted (7 years 8 months 2 weeks 4 days 3 hours ago) and read 5305 times:

Quoting EssentialPowr (Reply 20):
Is there something that can be excluded from being a significant safety item? What is a significant safety item? Could be a multitude of things; even the security/power up check can have huge safety impacts. If a company wants to set flaps with the receiving checklist, and that is approved in the opspecs (via the FAA) then that becomes the procedure.

Please read what others have written to avoid duplication.

Wow, testy reply... I actually thought we were all contributing to the discussion!

That said you and I both know that numerous items are excluded from checklists that are still part of company mandated flows in many cases, items which are NOT significant safety of flight items hence why there isn't a secondary check.

For example: remembering to switch a radar screen to terrain imaging with EGPWS prior to takeoff (although that is company procedure on a flow lets say) may not be backed up with a checklist since failure to do this will not result in a critical loss, the verbal warnings for terrain will still function.

Flaps are a significant safety of flight item because in many cases the aircraft simply won't fly off most runways without them.

There is a difference IMHO, and from what I have seen in the eyes of the FAA, Aircraft Manufacturers, and Aircraft Operators.


User currently onlineSilver1SWA From United States of America, joined Mar 2004, 4737 posts, RR: 26
Reply 24, posted (7 years 8 months 2 weeks 4 days 3 hours ago) and read 5292 times:
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Quoting Canyonblue737 (Reply 19):
A significant safety related item, such as setting flaps for takeoff is ALWAYS dictated by company SOP (standing operating procedure.) What you were seeing is variations between companies, and the fact all the UA pilots set it while in motion while the WN pilots did it before taxi indicates all were following their particular companies SOP. It is becoming more common in the industry to set flaps prior to taxi, in fact to do almost all required checks prior to taxi (to allow pilots to focus on where they are going) but obviously there are still tons of variations on how to fly an airplane.

All are safe, and everything you saw was normal and standard. Also remember all airliner aircraft have systems to warn pilots that they didn't set the flaps properly if they attempt to takeoff without them.

You are 100% correct. WN's SOP is to set flaps prior to taxi. UA sets them during taxi. Both companies do it their way every time.



ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
25 EssentialPowr : This is a technical forum...Generic terms such as "safety" and "efficiency" are exactly that; specificity is the key. What is NOT a safety issue? Any
26 AirWillie6475 : I was in the BUS a few days ago at United they set flaps during engine start.
27 Silver1SWA : Wow, didn't take long for someone to throw an exception at me. A couple months ago, I was wing-walking one of our 737s (WN) out. I barely finished my
28 Canyonblue737 : Ok a few simple things, and again this is all for point of discussion not to create some kind of fighting match over terms... 1. In regards to flaps
29 EssentialPowr : Right. All it took was 1 accident at DTW; so that's not really a safety issue, "most" of the time... Only you can define what a "CRITICAL SAFETY ITEM
30 HAWK21M : Isn't there a Cockpit to Ground Confirmation on LEDs Extended. Irrespective.The Crew Checklist will cover LEDs extended & Cross check ovhead lights p
31 Silver1SWA : I'm not really sure what you are asking and why. But if it has to do with what I said about it scaring the sh*t out of me, I meant that it scared me
32 Post contains images Bri2k1 : I haven't heard of this before. Doesn't the 737 have a LE FLAPS EXT indicator below the flap position gauge? It's illuminated in green in these photo
33 Canyonblue737 : We are talking about the same thing and in totally agreement! Again, again, again... failure to set flaps equals likely loss of the airframe, crew an
34 Post contains images HAWK21M : LED Flap/Slat Annunciator on P5 Annunciator on P2 In Addition on the P5 Aft Ovhd Panel to the Right tou have the LED Annunciators too. But on Start u
35 EssentialPowr : I have a bit of experience in human factors, and what you have written is obviously a worthy goal. The point is that every operation must determine w
36 KAUSpilot : Just wanted to add that at my company we will not extend the flaps on the ground until both engines are started. In this day of fuel coservation, we w
37 EssentialPowr : trim in the green flaps at t/o parking brake not set spoilers stowed... what'd I forget re: the config horn on the erj?
38 KAUSpilot : I believe you got 'em all.
39 AirWillie6475 : That's strange, why somebody in the past has tried to takeoff with one engine?
40 2H4 : Plenty of Skymaster pilots have.... 2H4
41 EssentialPowr : re: inadvertant single engine t/o; I believe in happened at Cont Exp. on the ATR as well...
42 KAUSpilot : Yes, it has happened, luckily it will simply result in an aborted takeofff, since the condition will be obvious once powered is applied and the plane
43 EssentialPowr : Spool times on 737s, esp. Classics with high time engines, can be significantly different resulting in a rapid turn due to the asymetry, which is why
44 KAUSpilot : Ahhh, good to know...I've always wondered why they did that when I'm up there on the j/s.
45 CX flyboy : We set flaps, trim, turn off APU, check the EICAS recall and engine anti-ice all after engine start and before we taxi. We used to set trims and flaps
46 EssentialPowr : I agree w/ most of that post, w/ the exception of the above quote. From 1 major's perspective, the captain is in command, and no flows/checklists are
47 Usair320 : I know both AA and DL pilots set the flaps during the initial start-up of the engines.Also on my recent WN flight from ABQ-PHX the crew didnt extend t
48 HAWK21M : Any of the below not in configuration stated. Parking Brake Released Spoilers in Down Detent Flaps/Slats in T/O range. Stablizer in Green Band. & Thr
49 CX flyboy : At my airline, all pilots are regarded as Captains in training and are encouraged to be a part of any decision making process as much as possible. Ob
50 Post contains images 2H4 : Anti-CRM dinosaurs take note; CX and virtually all safe, modern airlines have realized exceptional success with this philosophy. Despite having to de
51 EssentialPowr : Good point, Thank you. I believe in that philosophy as well, but like the concept of the tone and pace of the cockpit being established by the captai
52 Usair320 : Yep. Atleast the 732/733/734/735. Not too sure about the NG's.
53 FlyMatt2Bermud : Some airlines/commuters like Airtran and ASA seem to leave their flaps at the takeoff setting while taxiing to the gate. This is not regular but it is
54 Post contains images HAWK21M : B732 basic B732adv The Difference is with the Slat positions apart from the 1&6. In the below pics Lookat the Left top corner. B732 B733/4/5 B737NGs
55 Usair320 : Thanks, Very useful info.
56 CX flyboy : Even at my airline the captain quickly sets the tone. Every pilot is different in personality and despite very strong adherence to SOPs and good leve
57 TWAL1011727 : On AA/DL/US/NK/CO (guess it-they all flew out of MLB at one time or another) they ALL extended flaps after they started to taxi. Generally before the
58 ThrottleHold : ...isn't the PF always flying? Otherwise he'd be the PM!!
59 CX flyboy : haha...right you are!! I meant when it is someones turn to be PF!
60 ThrottleHold : Excellent post. If only every airline could be this way.
61 HAWK21M : Possibly, as the B752s dont have that in their Checklist. regds MEL
62 CosmicCruiser : We started what became CRM in the middle 80s and I believe most of the other American carriers had began to implement their version about the same ti
63 ThrottleHold : Some are, some definitely are...!
64 CosmicCruiser : I was just stating that there are no carriers here that do not have some sort of CRM program or still support the "capt. is God" mentality that I kno
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