B738 Flap Indicator freeze

[flyzhz]

Can anybody tell me how to know the flap position if the flap indicator freeze?
It happens on the SIM,during a normal approach affter trailing edge flap disagree,the flap lever is 5 and the needles point to 1 .

Then I follow the QRH "Trailing Edge Flap Disagree" Plan to extend flaps to 15 using alte rnate flap extension.When the needles point to 5,the Landing Gear Configuration Warnings begin.

At first I think the flap indicator freeze,but I can use the Landing Gear Configuration Warnings to find out the actual flap position.Because the alttitude is baove 800RA,so the flap is not 0 to 10;then if I push and pull the thrust lever to see whather the sound stop,if it stop ,the flap should between 15 dan 25,if not, the flap should be more than 25.

As my FCOM says:
Aural Indications
A steady warning horn is provided to alert the flight crew wh enever a landing is
attempted and any gear is not down and locked. The landing gear warning horn is
activated by forward thrust lever and flap position as follows:
Flaps up through 10 –
• altitude below 800 feet RA, when either forward thrust lever set between
idle and approximately 20 degrees thrust lever angle or an engine not
operating and the other thrust lever less than 34 degrees. The landing gear
warning horn can be s ilenced (reset) with th e landing gear warning
HORN CUTOUT switch
• if the airplane descends below 200 feet RA, the warning horn cannot be
silenced by the warning HORN CUTOUT switch.
Flaps 15 through 25 –
• either forward thrust lever set below approximately 20 degrees or an
engine not running, and the other thrust lever less than 34 degrees; the
landing gear warning horn cannot be silenced with the landing gear
warning HORN CUTOUT switch.
Flaps greater than 25 –
• regardless of forward thrust lever position; the landing gear warning horn
cannot be silenced with the landing gear warning HORN CUTOUT
switch.
The warning indication is cancelled when the configuration error is corrected.


But then I am hesitent that is the warming activated by trailing edge flap position or the flap lever position?

B737 Ryanair Cockpit Companion says:the horn is activated by trailing edge flap and thrust lever position.
if normal AC power is lost, indicator will freeze,no asymmetry protection-
making a selection with the flap lever sends a measured voltage to the gauge -if you select 1 and the gauge gose to 5, you've had a loitage spike and probably a tripped CB.

Maby the warning systerm is wrong?I don't know.

[TheChitterneFlyer]

Then I'd surmise that the point where the flap asymmetry system detected the asymmetry was at or around 5

[BOAC]

Got a QRH? You can alaways looka out of da winder if you really want to know (NB Not in the SIM) - but why do you?.

[RAT 5]

If the TE's freeze due to a problem you are not going to move them any more, so I'd assume they are at the indicated stuck position and the QRH will lead you to the correct Vref for landing.
Should you lose power to the gauge, but the flaps are working, then you either trust the flaps are where you select them, (feel the trim change and the required N1% makes sense), or you select land flap very early and have the F/O on the cabin telephone looking at them. Not the best use of pilots close to landing, but..... and may be dis-allowed by security SOP's.

[777AV8R]

Can anybody tell me how to know the flap position if the flap indicator freeze?
It happens on the SIM affter trailing edge flap disagree,and point to 5.

After an asymmetry trip it doesn't matter any more. Follow the QRH and do the procedure.

It works the same in the real machine too.

[ImbracableCrunk]

The speed tape might have some relevant info if it's simply a indicator problem.

[flyzhz]

BOAC,I think your ideal is good.

[WYOMINGPILOT]

The same thing will happen if you lose the Left AC transfer Bus ie Left Generator dies and the APU won't pick it up. You have to use pilot judgement as previously discussed. Look at the speed tape, look at the overhead Leading edge device annunciator panel, landing gear warning horn and pitch and N1 changes as you extend flaps, all will give you good information.

[RAT 5]

Be careful with the speed tape: the F bugs come from the flap lever NOT the flap gauge or the flap position.

[de facto]

Be careful with the speed tape: the F bugs come from the flap lever NOT the flap gauge or the flap position

True but the Vmax and Vmin come from the actual flap position and aircraft weight giving you a good idea if it is a flap indicator problem or not.

[TheChitterneFlyer]

Can anybody tell me how to know the flap position if the flap indicator
freeze?
It happens on the SIM,during a normal approach affter trailing edge
flap disagree,the flap lever is 5 and the needles point to 1 .



Flyzhz - You've now edited your original post, but my comment still holds good.

The flaps have stopped at or around 1 because of a disagreement between each of the wing flaps and the asymmetry protection system has done the right thing by freezing any further flap movement. You've selected flap 5 and the flaps have stopped at 1... isn't that enough of a clue that there's something amiss? If, having selected flap and the flap failed to move... then by all means use the alternate system as per the QRH (with caution; because you DO NOT have any asymmetry protection during alternate operation).

I suspect that you're not what you might want us to believe i.e. in my book, you're most definitely NOT a professional pilot and more than likely an armchair pilot who "thinks" he knows what he/she's talking about.

Top Tip... learn how to spell!



Maby the warning systerm is wrong?I don't know.


You're right... YOU DON'T KNOW!

[flyzhz]

Hi,Flyer! First,thanks for your help! I edited it so people who wants to help can know it better. I do not know ,so I am here looking for help, and I am not ashamed of this.I have never said I want anybody to believe who I am,cause that does not matter to me.I really appreciate your help! But I do not know why you are so angry,is there anything I can help?Anyway I hope good people better life.

[BARKINGMAD]

RAT 5. Security SOPs preventing flight crew from inspecting their 'frame as part of diagnosis???

Please let's bury this one before someone reads it and is afraid to go down the back or send F/O to check for bits misaligned or dropping off or crap de-icing ! ! ! ! ! ! ! ! !

Otherwise the mad mullah in his Afghan cave with a laptop (excellent broadband coverage in the hills!) will be scoring more hits in the Jihad??!!

:ugh:

[ZFT]

The flaps have stopped at or around 1 because of a disagreement between each of the wing flaps

I have no knowledge of the NG but on previous variants of the B73 the asymmetry detection was solely a function of flap indicator needles disagreement. Is the NG the same?

[flyzhz]

The FSEU monitors the TE flaps for asymmetry and skew conditions. It also monitors the LE devices for improper position and skew conditions on slats 2 through 7.The FSEU provides protection from uncommanded motion by the LE devices or TE flaps.

[flyzhz]

Hi Flyer,I read what you said again and again. When the needle stopped at 1 ,the flap position maybe 1.So you are right here. But my question is after the warming ,where the flap should be?Can I use the warming to find the flap position? I have got good ideals to find out the flap position from people who knows what he was talking about. How about you,you also know that,do you?

[RAT 5]

B.Mad: Totally agree. We could start a whole new thread on that one issue, but that's not an invitation.

[Fredairstair]

You can use the appearance of the flap speed limit on the PFD to give you a clue if the flaps have run - eg 175kt for F30. This is useful for example when you're on standby power and the flap pos indicator is inop.

Also what WYOMINGPILOT & de facto said above.

[flyzhz]

Thanks for your help ! I think I know more now.