737-700 ALL ENG at LSK 4L

[gumbyjan]

[FONT='Times New Roman','serif']I have a question which has us all here stumped. We have 5 737-700s with the 10.7 software. The small fleet and pilot population do not give us much to go on so I am referring to the expert. I doubt you will get stumped but feel free to pass this along if needed.[/FONT]
[FONT='Times New Roman','serif'] Here is our situation. After a Flaps 1 takeoff and reaching level off height we select 210 knots (not up for reasons of ATZ rules here in the kingdom) and once we reach the 1 caret we select flaps up and select N1. After reaching 2500AGL (again a kingdom thing) we select VNAV expecting the speed bug to move to 250kts. What happens many times on one particular airplane is that the speed bug reverts to the UP speed. Neither changing the climb speed on the climb page or the CI or any other speed changes do anything. We also wiggle the flap handle, check the flap and LED positions, and generally scratch our heads to no avail in changing the speed bugs position. [/FONT]
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[FONT='Times New Roman','serif']The one thing that I can find is on the climb page. Instead of MAX RATE, MAX ANGLE, ENG OUT I find a ALL ENG prompt at LSK 4L. Selecting this and executing then selecting ECON and executing will fix the speed Bug. What gives? The engines are both running! We usually notice an engine failure. [/FONT]
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[FONT='Times New Roman','serif']I am a training Captain here and it is getting embarrassing when I have to say "I dunna know, but here is the fix”. Any help would be appreciated! [/FONT]
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[FONT='Times New Roman','serif']I appreciate you all thinking this one over. Blue skies.[/FONT][FONT='Times New Roman','serif'][/FONT]
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[FONT='Times New Roman','serif']Joe Nepute[/FONT]
[FONT='Times New Roman','serif']Contact Me at:
Box 10498 C/O Saudi Aramco
Dhahran 31311, Saudi Arabia
Phone: [phone]
cell: 966-50-683-4080
E-mail: [email protected]
or [email protected][/FONT]
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[Denti]

There is a known bug in FMC version 10.7. If you test the config warning on the ground by momentarily pushing forward only one thrust lever (or pushing forward only on thrust lever for whatever reason) the FMC thinks there is an engine failure as the difference in thrust lever angle is too big. It automaticly switches into one engine out mode and therefore uses the corresponding speeds which are usually the minimum speeds.

That is the reason why you get the ALL ENG prompt which after activation switches the FMC back into the all engine operating mode with normal speeds.

It is a known problem and you should have a technical information bulletin from boeing about it in your documentation.

[LAHSO 06/03]

Hello Gumbyjan,

Sounds like you have experienced one of the known problems that come with your 10.7 software update only, here is what happens:

After departure the climb page goes in single engine mode, after some basic conditions for this to happen have been met:
Thrust lever position difference exceeds 52 degrees and ground speed greater than 30 knots.

If you get this message in the air, simply have the PM press the LSK 4L button and execute to get back into dual engine mode
...after you have seen it once a non-event really

Now, i'm sure you are puzzled about the basic condion, but I suspect your company allows for single engine taxi. It could be the previous crew have exceeded the taxispeed of 30 knots (and the airplane electics have not been powered down) before you took the aircraft from them.
To me it may even be they did not exceed that taxispeed or have had the difference in thrustlever position, since it is an anomaly in the software.

I did not cook all this up myself; it's all in the Boeing FCOM bulletin dated june 11, 2007 (your operator should have distributed this to you).

Safe flights,

[gumbyjan]

ALL ENG out at LSK

Thanks to all on this one!

Seems since we got the AD for the config horn and to brief it every flight to put on your oxygen mask some of us, to reinforce the point, push up the thrust lever to make the horn honk for our brief. Another idea gone wrong.

Cheers

[BOAC]

gumby - just do it before engine start (both throttles) like wot I used 2. It used to infuriate the hide-bound BA gang - 'I say, that's not standard'.................