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-   -   737NG flaps 10 (https://www.pprune.org/tech-log/506237-737ng-flaps-10-a.html)

N1 Limit 25th Jan 2013 20:19

737NG flaps 10
 
Hi there
I need your contributions for this: yesterday as i was on approach about 7 miles from touchdown established on the glide with flaps 5 my speed was a little high for the flap i was using around 176 and the skipper was urging me to quickly slow down to me it wasn't a big deal i'm used to approach a little faster for this flap config,he was pressurizing me to slow down and i then requested for flaps 10 and he told me that flaps 10 isn't to be uses as speed brake and that i should ask him for gear down instead which i did.But going back to the FCTM this is what i've found:During maneuvering for an approach,when the situation dictates an earlier than normal speed reduction,the use of flaps 10 with gear up is acceptable.
According to my skipper flaps 10 impose a stress on the wing.Anybody to shed a light with me on the matter?

TypeIV 25th Jan 2013 20:31

Some captains refuses to extend flaps 1 unless there is like a 25-30kt marigin in still air :ugh:

Hotel Charlie 25th Jan 2013 20:37

Sounds like a low timer Captain! He'll figure it out in a few years ... Good luck and Enjoy :ugh:

safelife 25th Jan 2013 20:38

Use flaps to slow by extending them close to Vfe and that aircraft WILL develop flap problems eventually. Especially the 737.

Hotel Charlie 25th Jan 2013 21:41


safelife Use flaps to slow by extending them close to Vfe and that aircraft WILL develop flap problems eventually. Especially the 737.
Did you read the post? Flap 10 at 176 Kts .... come on!!

Skyhigh86 25th Jan 2013 21:52

yep extending flaps 10 out at 176 is certainly not going to cause any issues down the line.

Flaps 10 is great if you are struggling to stay on the Glide and a/c's speeding up. This can happen quite often with tailwinds.

ImbracableCrunk 25th Jan 2013 23:39

F10 to hold speed on the G/S is great. F5, not enough? Go for F10!

misd-agin 25th Jan 2013 23:55


TypeIV -Some captains refuses to extend flaps 1 unless there is like a 25-30kt marigin in still air :ugh:
There's no benefit in typical ops for extending flaps at higher speeds. Guys get 5 kts under the maximum limit - "Flaps 1". :{ Sometime later the throttles get pushed forward. Guess they didn't need that much drag afterall. :ooh:

The slower the speed at extension the easier it is on the a/c and the more efficient it is. :ok:

B737900er 26th Jan 2013 01:57

Flap5 and flap 10 are the same speed (vref40+30) if anything it gives you a steeper rate of descent for the same speed.

de facto 26th Jan 2013 09:40

He wanted you to slow down in a hurry,well at 7 miles speed 176 ,flaps 10 wint do much to you.
Eventhough gear may me a tad too early,it wont hurt too much either,you wre fully configured around 1500 ft..
Maybe it is his comfort zone or maybe there is something we dont know.
Flaps 10 as mentionned is great to help in increasing a tad your descent rate or not allowing speed increase on the glide with winds changing into a tailwind but sometimes the gear is the easiest option.
You will have plenty of time to practice those idle thrust to 500 ft when the time comes,your capt was maybe tired or junior,in anycase you can prove yourself later.
I have let a few fos who insisted to practice idle thrust to the limit perform a go around because at the end they put the gear a tad too late..a good eye opener for fuel saving record..

Checkboard 26th Jan 2013 09:54


"During manoeuvring for an approach,when the situation dictates an earlier than normal speed reduction,the use of flaps 10 with gear up is acceptable."
Note that this statement says that using the flap to achieve a lower speed while manoeuvring, while keeping the gear up, is OK.

That is a great deal different to "extending the flap at high speed, to increase the drag in order to slow down" - which is what you were attempting, and the Captain was warning against.

If you need drag, because you are fast - add drag.

If you need lift, because you are reducing speed - extend the flap.

Your Captain was correct.

ImbracableCrunk 26th Jan 2013 12:39


Note that this statement says that using the flap to achieve a lower speed while manoeuvring, while keeping the gear up, is OK.

That is a great deal different to "extending the flap at high speed, to increase the drag in order to slow down" - which is what you were attempting, and the Captain was warning against.
I wouldn't call 176knots "high speed" for flaps 10.

RAT 5 26th Jan 2013 14:17

"During manoeuvring for an approach,when the situation dictates an earlier than normal speed reduction,the use of flaps 10 with gear up is acceptable."

You say the speed was a little high at F5; i.e. it was above the green bug for your weight, but it was not too high for the flap itself. I assume this was the scenario and the speed was not increasing. F5 idle thrust will hold a 3' glide path and thus not slow you down. The next action I assume was going to be gear down F15 about 4nm out. I don't know your weight, but I guess you were about 10kts too fast. So why not put the gear down at 5nm? That'll achieve you being at the correct speed for F15 at 4nm and use less fuel than dangling the Dunlops too early. There was no need to panic. F10, with the LED's going to full ext is perfectly acceptable, and is a good way to lose 10-15kts in 3-4nm. However, if your captain wanted to slow down 10kts in 3nm why not use that which is designed to do it = speed brakes. OK, I know, they are not too effective at slow speeds, but they will work over 3nm for such small adjustments. They are variable drag, while the gear is fixed drag. Once down it is down. Too early means more fuel & noise.
note: if at 7nm you are high & fast and not sure if your increased ROD at F5 (V/S and thus speed increase) will save the day, then gear is a great idea. I find too many low hour F/O's reluctant to use it thinking they'll get away with it by 500'. Their neck hairs have not yet become prickly enough. When they do start to twitch it is often too late.

Denti 26th Jan 2013 15:06


F10, with the LED's going to full ext is perfectly acceptable, and is a good way to lose 10-15kts in 3-4nm.
I guess that depends what kind of NG your flying. On the 900 and many 800s they won't go to full extent at F10.

nick14 26th Jan 2013 15:16

They certainly do on our 800's

Perfectly acceptable at that speed in my opinion

captjns 26th Jan 2013 15:26

Flaps 10 work pretty well with the SFP birds:ok:. With the non SFPs with the LEDs in the FE position the jets slows a tad too much requiring a bit of thrust for the G/S... about 40% n1.

Heck if Mr. or Mrs. Boeing did'nt want us to use Flaps 10, then why put a detent there:hmm:.

RAT 5 26th Jan 2013 16:36

"Heck if Mr. or Mrs. Boeing did'nt want us to use Flaps 10, then why put a detent there."

I'd always thought it was left over from B732 which had a fixed speed schedule of 210/190/180/170/160/150 for up/F1/F2/F5/F10/F15. In USA I believe ATC liked to use these speeds for 'pushing tin' and crating & maintaining correct spacing. I believe 160kts was a common speed on approach, as indeed it is at many UK airports.

Denti 26th Jan 2013 17:44

Of course its perfectly acceptable, just saying that the SFP 800s dont go to full extent at F10. Many airlines chose those nowadays as there is usually not much if any of an extra cost, depending on price negotiation during purchase of course. In "my" outfit nearly all 800s now are equipped that way, so for us it is unusual to fly ones with the old LE schedule.

framer 27th Jan 2013 00:30

At the end of the day you were only two minutes from touchdown and the Captain wanted you to dump the gear. Just do it and it is no big deal. Half the time he or she may have seen something you missed while you were concentrating on your low drag approach anyway ie an aircraft taking their time to line up or a tailwind starting to come in or the preceding aircraft looking like they'l miss their high speed. Or, that particular Captain may just be more conservative than you and that is how they operate. Or, they may have just had to do a go around last week because of an FO who was less highly skilled than yourself cocked it up, so now they are a little cautious.
Basically if the Captain thinks it's a good idea to take the gear at 2100ft then who's place is it to say otherwise?
The main thing is that it should not be taken personally. It is not a slight on your ability to fly an approach, it is simply what the PIC thinks is best at that moment. Don't hold it against them for being conservative, one day you might decide to be a fraction more conservative too.....that happens.

de facto 27th Jan 2013 08:10

Framer,

Exactly my opinion.


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