737 speed tape: help needed !

[bultaco]

Hello,

Quick question about the flap retraction schedule on the 737-800.
When you reach flap retraction altitude and speed up to retract the flaps do you need to pass "1" on the speed tape before putting flaps to stage 1 and then pass "up" before you retract the flaps completely ?

bultaco

[5150]

No, you can retract to 1 betweek 1 and 5, then retract up between 1 and UP (hope that makes sense!)

In all cases, make sure you're accelerating through the minimum speed (ie you've got the trend arrow indicating an acceleration).

[Pilot Pete]

No. Assuming a Flap 5 departure, as you pass "5" and you are accelerating, you select Flap 1. As you pass "1" you select Flaps Up. Main points to note are that you must be accelerating and if you fly 'at' any of the selected flap settings you need to fly at the corresponding speed for that setting (i.e. if you stopped retracting the flaps at Flap 1 for some reason, you need to fly at a minimum of "1"). I have had pilots just call for the start of flap retraction without checking that their attitude actually has the aircraft accelerating.
If you get a flap malfunction during flap retraction, then you need to fly the minimum speed for the minimum amount of flap you definitely have, say if they stopped moving towards Flap 1 upon selection from Flap 5, then you need to fly the Flap 1 ("1") speed as a minimum, as that is the maximum amount of flap you can say you definitely have... more of an issue if you are decelerating and have already moved the speed bug to the next flap speed. When decelerating we always teach PF to call for the flap required, PM select it, PF (and PM) check the Flap indicator to ensure the flaps are running before PF selects the next speed with the MCP speed bug.

PP

Edited to add that 5150 beat me to it!

[bultaco]

thanks 5150 and Pilot Pete for the fantastic answers .... I really appreciate them ! :)

[Pilot Pete]

P.S. Do you have a Bultaco?

[5150]

No probs
Pete - I'm sorry mate! You'll just have to get up a bit earlier next time!! :E

[PA28pilot]

Just as clarification to the previous comprehensive replies, there is no '-5' speed displayed after a flap 5 takeoff, only '-1' and '-UP'. Retraction from 5 to 1 can be initiated above V2+15 (the "white bug") and accelerating.

Similar for a flap 15 departure: Retract from 15 to 5 when above V2+15 (and accelerating), 5 to 1 at '-5' and 1 to Up at '-1'.

A flap 1 takeoff is slightly different, retract from 1 to Up passing '-1'.

Reference: FCTM, 3.26.

Regards,
PA28pilot (who also flies 737s!)

[Pilot Pete]

PA28Pilot

Well spotted about the "5" or lack of, with a flap 5 departure! :rolleyes:

PP:ok:

[bultaco]

Hi Pilot Pete,

Yes a Bultaco Pursang - many use to be used by Bord na Móna (peat producer in Ireland). To drive on the bog roads.

[clonemole]

Hi,
Im a trainee on the 738.. pre-sim stage .. so kindly excuse me if this question has a really obvious answer, but what is the use of the Vref+15 white bug? Since we maintain only Vref+5 generally on approach.

[Cough]

Hi,
Im a trainee on the 738.. pre-sim stage .. so kindly excuse me if this question has a really obvious answer, but what is the use of the Vref+15 white bug? Since we maintain only Vref+5 generally on approach.

If anything like the classic, you would retract flaps from 15->5 above that speed in the case of a G/A.

[Pilot Pete]

Nice one Bultaco!:ok:

Clonemole

It is to do with manoeuvre margin. If you are slower than V2 + 15kts you do not have the required overbank protection, hence if you have an engine failure on takeoff your initial speed target is V2 to V2 + 20kts. If you are at anything below V2 + 15kts then you do not have the required overbank protection and hence the 'blanket' rule that any initial turn is limited to 15 degrees AOB. Here is what the FCTM says;

Immediate Turn after Takeoff - All Engines

Obstacle clearance, noise abatement, or departure procedures may require an
immediate turn after takeoff. Initiate the turn at the appropriate altitude (normally at least 400 feet AGL) and maintain V2 + 15 to V2 + 25 with takeoff flaps.

Note: A maximum bank angle of 30° is permitted at V2 + 15 knots with takeoff flaps. After completing the turn, and at or above flap retraction altitude, accelerate and retract flaps while climbing.


Immediate Turn after Takeoff - One Engine Inoperative

Obstacle clearance or departure procedures may require a special engine out
departure procedure. If an immediate turn is required, initiate the turn at the
appropriate altitude (normally at least 400 feet AGL). Maintain V2 to V2 + 15
with takeoff flaps while manoeuvring.

Note: Limit bank angle to 15° until V2 + 15 knots. Bank angles up to 30° are permitted at V2 + 15 knots with takeoff flaps.


If you look in the FCTM there are graphs which show the Manoeuvre Margin to Stick Shaker and you can see how the various flap settings and speed keep you on the safe side! The following is from the narrative related to these graphs;

When reviewing the manoeuvre margin illustrations, note that:
• there is a direct correlation between bank angle and load factor (G's) in level, constant speed flight. For example, 1.1G corresponds to 25° of bank, 1.3G ~ 40°, 2.0G's ~ 60°

I believe it is a certification requirement for a 15 degree overbank margin when in a 30 degree AOB turn.

Hope this helps and good luck with the course!

PP

[clonemole]

Pilot pete..
Thanx for the detailed reply.
My question though was regarding VRef. :}
On approach we get a white Vref+15 bug on the tape. Any idea wht thts for?

Cough..
I dont think i understood ur reply since a go around requires flap retraction to 15 from landing flaps right(2eng)? So is it that past this Vref+15 bug u move to 5 from 15 or to 15 from ldg flaps?
I thought the retraction would be according to the green flap bugs.:hmm:

Man these smileys are gr8

[Rainboe]

Hint- if you are an adult now, leave the smilies out. Leave them out altogether. And cut out the text speak, then we might communicate!

[Fredairstair]

Rainboe, you grumpy old bugger! Don't you know the kids are never wrong?

Seriously though, while I can't bear txt spk, I do think the "smilies" or "emoticons" do have a role in these websites. Not everyone is capable of expressing exactly the message they're trying to convey with words. I know that sounds a bit odd, but it's true that the majority of communication is non verbal; body language, inflection and tone have a huge role in the interpretation of the words we use. So while I partly agree with you, I'd ask you to give these daft wee things a try. :ok:

[Cough]

Cough..
I dont think i understood ur reply since a go around requires flap retraction to 15 from landing flaps right(2eng)? So is it that past this Vref+15 bug u move to 5 from 15 or to 15 from ldg flaps?
I thought the retraction would be according to the green flap bugs.

The G/A procedure requires the flaps to be retracted to 15 as part of the initial actions. At Aa, to retract to flaps 5 requires you to be accelerating (same reasons as pilot pete says) and beyond Vref+15. Again, if similar to 73 classic.

[clonemole]

Cough.. Ok understood!

Fredairstair.. I agree. Btw my favs are :} and :E lol