737-800 flap position indicator.

[sky-738]

For 737-800,when the flap position indicator is inop , how can you make the landing configuration? somebody said that using the red and black line in the PFD . but my question is :is the red and black speed limit indication accociated with current flap position or the flap handle indication? is that reliable to assure the flap is in position when the flap position indicator is inop?
THX to you all.

[stator vane]

check MEL

it does not allow dispatch with that gauge inop due to its omission; at least in our current version.

if it occurs in flight: one could use the overhead annunciator.

if that also is inop, use QRH for a no flaps landing and find a long runway.

otherwise: become a self appointed fight test pilot and prepare for reams of paperwork afterwards.

[Cough]

Stator.

I would rather:-

Select flap 1. Check the pitch/power datums contained in the unreliable airspeed drill are achieved.

Select flap 5. Again check....

Continue selecting and checking.

When you achieve flap either 15 or 30 stop and land in that configuration.

Flap 0 landing is possible, I don't doubt you, but you would minimise risk by using flaps!

[Pub User]

I believe the speed-limit indication is driven by the flap handle position; you can see that because it moves instantly when flaps are selected. However, the amber minimum manoeuvre speed indication, and the stick-shaker threshold indications move in accordance with actual flap position; again this is clearly visible when flaps are running. So, provided it is just an indicator problem, and not a FSEU failure, you should be able to rely on those indications to assist your decision-making process in an emergency. You can also look out of the cabin windows, of course.

[Lord Spandex Masher]

If Boeing had been really clever they'd have painted indicators on the fairing that you can see from the cabin...

[sky-738]

Pub,
I agree with you , but is there any better way to make the flap position clear without the indicator?

[BOAC]

The chances of an inop gauge AND flap failure to extend correctly are miniscule. If no needle movement seen, note if there is trim/power change - if so, . Pop back into cabin and see if they 'look right' with no roll up front. Gear and land flap early. Make a Cough check. No adverse characteristics? Make an overhead indicator check and a Cough check on finals. Land.

[misd-agin]

Straight and level flight at constant airspeed. Extend flaps one notch. If the plane slows you have flap extension.

Stabilize at new configuration and speed. Extend flaps one notch. Check a/c slows.

Repeat again and again.

No unusual roll show symmetrical extension.

Slow to slightly lower than Vref at altitude to verify a/c handling. If normal handling continue but if it's not increase Vref/Vapp, plus buffer, above the speed that the abnormal handling occurred.

[de facto]

but my question is :is the red and black speed limit indication accociated with current flap position or the flap handle indication

Both are taken into account by the SMYD,just that the flap lever position is used by the FSEU to detect TE flaps uncommanded motion(UCM)and as pub user said when to display the upper speed limit.
The red and black(mini maneuver/stall shaker)is calculated by the SMYD which uses many sources for calculation such as thrust setting,use of engine anti ice,(DEU), angle of attack(ADIrU),info from the FSEU(LE assymetry,UCM),TE flaps ACTUAL position from the proximity sensors,TE flaps LEVER position via sensors...all these to get the highest BiAs and the red black is then displayed.

The FSEU is using both flap lever handle position and actual flap position to give you info on the indicator,if they dont agree for example the indicator will stop and you will have a TE disagree scenario,same for an assymetry....

The important thing to remember in your scenario is that the speed limit is not sufficient at all for checking proper flaps deployement.
The TE flaps are manually selected by you and a cable will give info to the CPU,the CPU will then order the PDU(power drive unit) to use hydraulic to move the torque tubes that drive the flaps down.
The mechanical input command for TE will also move the LE control valve.

So if you have Hydraulic power and the TE flaps dont move on the indicator,you will follow the disagree checklist.
The electrical motor of the PDU should get the flaps down.....if the flaps still dont come down,then as BOAC said you are a test pilot.
I would highly consider,in that case the failure of the indicator a probable cause and check the CB..possibly reset it.
If that doesnt work and if the LE flap /slat agree with your TE flap lever position,and your thrust versus pitch...i would configure for flaps 15 and add 10 kts to VREF in case you were in icing for maneuver issues...
Landing distance flaps 15 is about the same as 30.

[Sciolistes]

if the flaps still dont come down,then as BOAC said you are a test pilot.

You could also be on standby power, not a situation when you want to start faffing about wondering what position your flaps are at - as that Ryanair crew discovered into Stockholm!

As Cough said, pitch and power...

However, the barbers pole will settle at the placard limit for the current flap if it has extended as commanded, so it is also a good proxy too.

[BOAC]

Firstly, I do not claim credit for the 'test pilot' line - it was stator vane.

Now, before we get too exotic with failures here, I read the OQ as a flap gauge failure - nothing more - no electrical or hydraulic failures/herds of charging elephants etc etc?

As young Cough said, KISS.

[sky-738]

THX to you guys ! learning a lot!

[de facto]

Maybe Boeing could put a OFF flag on the TE flaps indicator just as the one on the rudder trim....
Could help at least for those sim sessions....

[Cough]

First time I've been called young for a while....But its OK coz Miss little Cough has just assured me that I'm completely over the hill!

An off flag would be good!

(Oh I dream of flying the 737 again - LeBuuus isn't the same.....)

[BOAC]

First time I've been called young for a while

- everything is relative (as they say in incest.....)