Flap 'UP' Speed - 737NG
 

Have a query here folks

Upon flying a noise abatement profile on departure V2+15 to V2+25 is maintained until bugging the up speed at either the MFRA or 3000 AGL depending on airfield brief stipulation (standard NADP2 or 1?)

With flap retraction complete a few LTCs have implied that 'UP' speed should be maintained until the noise abatement procedure is complete. Although i believe nothing in our SOPs suggest this, I was led to believe that a mximum of the UP speed + 10kts could be maintained until above 3000 AGL and acceleration is initiated.

I would have had a tendency to 'bug' the UP speed + 5, giving a bit of leeway to the AFDS + A/T, especially in gusty conditions or with SID profiles that include fairly steep turns after departure. I have been told that I am incorrect to do so because I am 'breaking' the NADP profile?? However other sources has said that speed inadvertently dropping below the UP speed with the AFDS + A/T engaged has also brought reactions.

I also felt a slight drop below the UP speed was no big deal as the maneuver speed provides a certain margin incase of an inadvertent overshoot of a typical 25 degrees of bank. I realise it is bad airmanship and should be avoided however a reaction may be to reduce the bank angle if you anticipate an overshoot i.e during a steep climbing turn for example at a higher gross weight.

It has led me to be a bit confused about what is right and what is wrong. Above all, fly the aeroplane is the answer. Can anyone add their opinions. Are people's interpretation of SOPs, NADPs and Technical facts causing this uncertainty?

Thanks, CK

Firstly I would say refer to the B737 Flight crew training manual.
Boeing allow a manuovre margin in calculating buffet limits. This margin is usually .3G......ie allows for a .3G over and above an expected 1G manourvre. This (if level flight and constant speed is maintained) coresponds to 40 degrees AOB. So you are correct in saying you have bank angle protection in the speed regime up to 40 degrees.(commonly called the yellow hockey stick) This is not to say that it is normal procedure to use it. Deviations (or I think you are refering to speed trend indications on the PFD) are to be expected as the trend indicates a dynamic parameter. That is to say that the input data is constantly changeing. Remember this trend vector indicates expected speed in 10 seconds if flight parameters remain unchanged. So what I'm saying is, small trend indications around the "Flap Up" indicator on the speed tape are expected in any aircraft and are normal. Sustained decreasing or increasing trend indications on the PFD must be dealt with appropriately by the pilot. As for you noise abatement concerns. The NADP will end as marked on the plate. Hope this helps. Happy to accept the obvious barrage that will folllow........my 2 cents worth.

I don't see why 5 kts above the up speed would bring reactions.I think its perfectly acceptable and good airmanship.Tell the guy who reacted to get a life ,stop being pettantic and fly the plane.

Maybe you should check your OM/B.

Vol. III says about AFS Systems:

"The autothrottle system also aids in windshear recovery by providing quick response to any increase or decrease in speed. The commanded levels of power may be beyond what the average pilot considers necessary but, in fact, are required by the situation."

I would interpret this suitable also for your question of flying the upspeed - if A/T is engaged no additional margin is necessary.

In addition our SOP/Vol. I says that no additional wind correction shall be applied when flying an approach with A/T engaged. So again i would say thats suitable.

But - isn't it somehow too sophisticated? Upspeed changes with grossweight, the heavier the upper your speed... differs during normal takeoff weight ranges about 10 knots, so who actually knows exactly what the upspeed is? 208 or 210? so...... well..... errrrm ;) just my 2 cents.

Thanks for your replys guys

SB7L - Yep, understand that Boeing have built in bank angle protection up to 40 degrees of bank (ie in level flight / constant speed) to stick shaker or buffet margin for the maneuver speed. Obviously no one wants to put this to test on the line! I also thank you for your comment re. the trend vector and understand it's concept. I am refering to an actual drop in airspeed below the up indicator with AFDS+A/T engaged, for example in a climbing turn as part of a SID. If it was maunal flight, I would simply reduce my angle of bank and pitch attitude. With AFDS+A/T in and LNAV engaged I assume the reaction is the same. The AFS is aware of min speed and wouldn't advertently attempt to fly a speed below it. The maneuver margin between the UP and the top of the yellow hockey stick is there as protection. Even entering the min speed range (never seen it happen, except in the sim) wouldn't activate the shaker, would it? At this point Minimum Speed Reversion would react. Assuming the pilot hadn't already?

Anyway, I am going beyond what I had originally asked. I feel the reason why I ask it is because some people are making mountains from mole hills!

They're not making mountains out of molehills. I expect your LTCs are thinking you are making a mountain out of a molehill because you apparently have a better idea of how the NG should be flown! I expect they would just like you to fly it like everybody else, and stop making your own little 'corrections' to SOPs! Listen to them and your Ops Manual and stop deciding you know better.

Thank you, Rainboe. What a highly constructive comment

I asked this question because I cannot get a definitive answer. I have asked LTCs/Line Captains etc and I got a variety of answers including the 'mountains from mole hills' quotation. The SOPs are vague in this area. They go as far as informing the pilot to 'bug the up speed.' They make no reference to the speed dropping below the 'up speed' or bugging 2/5/10 kts above the 'Up speed.'

If I check the FCTM I can educate myself on maneuvre speed protection. It's nice to know! I don't want to test its capabilities by thinking 'I know better.' I am just attempting to find out a little more about the aircraft that I fly. I like to think that I can quizz the knowledge of those more experienced to give me guidence. I then intended to take this to our trainers and see what they say, not simply by going 'Sod the SOPs, I'll do what the **** I like.'

I know who you are Rainboe. I know by your inputs to this forum that you have considerable experience in aviation. If you aren't prepared to share it with those wanting to learn, then don't. I care little for you making generalisations about how I operate the aircraft!

CK - if I may cool this down a little? I suggest your best option, in view of apparent non-standarisation in your training department (by no means a surprise) is to make a formal request for clarification of correct procedure to your CTC (as you propose) as long, of course, that this does not produce an adverse reaction! I think you are correct and wise in trying to clarify this apparent conflict of advice - you never know which side of the camp your next TRE is sitting in, after all:)

Incidentally, while you should get a reduction in pitch attitude I don't see the kit changing bank angle for you.

You will find that at no time do you bug extra when on auto. If the autothrottle was out, you would, but with it engaged, the throttle response is regarded as assured, and minor transgressions above and below bug speed are acceptable. Maybe one of the main philosophical points escaped you causing frustration amongst your trainers. An enquiring mind is always good, but established procedures are first priority . If you know a better way, take it up privately, but nobody wants to see someone working to their own unique techniques- it confuses everybody. I have had to stop people imposing their own particular limitations- one that springs to mind was 250kts below 10,000'. I dragged out the reason: 'birds!'. I said 'Stop that- it's not in the manual! When we share the same bit of sky, you lose! Bye-Bye Birdie. These people have paid for jet speed- how dare you impose a limit on them of turboprop speed! You are not giving them what they have paid for!'.

I would seriously advise you- don't confuse yourself and others at this stage. Fly as you are told. When you have some experience under your belt, come back and see your chief trainer and discuss then. Nobody wants (what they see as) a jumped-up novice trying to change things before he's learnt his trade.

I think you need to do a bit more reading about ICAO procedures?

I think a way of simplifying this so it does not get silly is ......that if the aircraft is not flying the targeted parameter for the given mode.......change the mode!! ie VS instead of VNAV and make an adjustment. Hours of debate over what to do??? when it's obvious!:ok:

.. ten deep breaths and a cup of coffee might be an idea before the combatants re-engage ?

The subject warrants discussion, not battle, chaps.

"Birds" are a VERY GOOD reason not to fly more than 250kts. under 10.000' Rainboe. Maybe you should start thinking about airmanship ?!?:ugh: Ever had a birdstrike with more than 250kts? I sincerely hope not as the result is not pretty.
If the procedure doesn't say that you can't do it, it is allowed as long as it is the safe option. voila! SOP's NEVER take priority over common sense and airmanship. NEVER and any proficient pilot knows this. Anyone not agreeing is a danger in the air.
About the speed bug: if you feel better to add these couple of kts., then by all means do so. For God's sake, don't these trainers have anything better to do than complain about these details which in no way affect the flight in a negative way?! STOP BEING PROCEDURE BITCHES!!!!! Yes, autothrottle function is protected, but the B737 autothrottle system is also weak(especially on the classic).

Also for me it sounds a bit like those molehills. When you turn up the speed and clean up on schedule, you set "Flaps up" when passing the green 1 - 20 kts before reaching the upspeed. So, when you are flying upspeed on the dot later on and get some speeddroppings by a few knots - i think that would be no other situation than a few seconds before as you were cleaning up, flaps moving up not having reached the upspeed?!?

Different view: If you're afraid of that you would have to set Flaps up when passing the upspeed mark and not when passing the "1"... or am i wrong now? Rainboe? BOAC?

And i wonder your question now. You wrote you've being told to "bug the upspeed". For me that means: set the bloody speedbug on your bloody upspeed and end of it... where's a problem at all... maybe am too confused after couple of spanish beer yesterdays eve, but well...

250 kts: clearly SOP in my company... its in our bible so as we are all christians we just do what the bible tells us to do :E

Mshamba - as I read it the problem appears to have been caused by 'differing' LTC inputs on how to fly this procedure. Boeing indeed suggest selection of bug up (or higher) at F1 and this is fine as it is a 'speed increasing' scenario as with all flap retractions (including OEI). The situation CK is asking about involves 'prolonged' flight at bug up (with manouevre) where the 737 A/T (commonly) does not control the speed well at bug up. As despegue says, the Classic is known for poor speed control and the NG certainly has its moments. We all know the 'margins' built in to the manouevre speeds but how is CK to handle being criticised for one method by one group and by the other for adopting the first's suggested method?

I am, however, not clear why any acceptable speed cannot be set at either MFRA or 3000' since noise is then finished? Why maintain bug up to 3000' if is not required? If you are holding v2+ xxx to an altitude, once you complete that stipulation surely you are then free to accelerate to desired speed IAW NORMAL flap retraction? What am I missing here?

A few anecdotes to amplify despegue's comments regarding birds for anyone tempted to ignore the threat:

1) I had a canopy broken at 300kts by a bird
2) An aquaintance lost an eye following a birdstrike (Hunter at low level)
3) A friend ejected from a Harrier off Belize following a high speed (not quite 600kts) (large) birdstrike which moved the whole engine a few inches back in the airframe.

Treat them with respect.

What can one say... some LTCs make better simulator pilots than airplane pilots... but that's another topic.

Look out for the South American Condor soaring in the Andes. Seen them as high as 15,000 feet:eek:!

Let's all reread the OP.
is not procedure. It's there in OMB Procedures. The LTC want him singing off the same hymn sheet as everybody else. We are not talking birdies in the Andes, fighter planes, 737 Classics- let's stick to why everybody should follow standard procedure.

- what you have missed is:-

1) There appear to be 2 'hymn sheets' as far as I can see
2) What do 'standard procedures' say about speed below 10,000ft in ICAO Class D and E? NOTHING to do with birds! The ANO is part of your Ops Manual. You should know it. It is Rule 21.

Definatelly you're not "breaking" the NADP. What you're doing is flying the plane like you want to do it, as you fell safe. And that captain who you were flying with didn't wanted to do so. So he told you that you were wrong... In spite of telling you " I don't want you to do this" !

Technically, I can't see what all the fuss is about - both ways have an adequate safety margin and little to no effect on performance.

However, I can see why some trainers might get concerned by a movement away from SOPs in their presence, especially in the "add a bit for Mum" department. They're probably wondering if there's a random increment to approach speed, engine failures are flown at V2+35 and 2T of extra fuel loaded when they're not around. Adding things on all the time "to make it safer" can get quite compulsive - and it often works in the opposite sense to that intended. Not implying that the OP does any of these, of course.

I'd hazard a guess that this is more a HF issue than a technical one, especially if CK occupies the LHS...