B737SFP
8th Jan 2016, 01:35
Hi guys...
Recently I did a LOFT session and we had a TRANSFER BUS 2 OFF (B737NG).
After running the checklist for this non normal, we couldn't re-estabilish that part of the electrical system (not even using the APU).
Long story short, we did a non normal checklist for every single amber light that was on, but...
During flap extension, the LE FLAP TRANSIT LIGHT remained ON (and the Flap Position Indicator Didn't work). Would you have asked for this NNC ? Affirm, right ?
Now things get interesting...
The LE FLAP TRANSIT NNC gives you the following options:
1 -
*Trailing edge flaps are extended and the trailing edge flap position indication disagrees with the flap handle position... How can you be sure that the TE Flaps are extended and the flap handle agrees with it's position ?
Anyway, let's say that you decided to go on with the next options...
**Trailing edge flaps are extended and the trailing edge flap position indication agrees with the flap handle position... This one will lead you to a F15 landing, but this should be because of a disagreement between the LE devices and the TE flaps (which would cause the LE FLAPS TRANSIT light to stay ON). Knowing the system, you will obviously check the LE DEVICE position indicator on the overhead and discover that that the LE Flaps/Slats are positioned correctly and that will make you scratch your head.
Ok... Let's see the next option !
*** Trailing edge flaps are up... This one doesn't sound right either. Anyway, if you decide to take this path, the checklist will lead you nowhere after cycling the flap.
Sooooooo, what would you do ? Would you simply disregard the LE FLAP TRANSIT light ? Assuming it was caused by the TRANSFER BUSS OFF in first place would you go on with the operation checking the LE DEVICES position indicator as you extend the flaps?
Does the FSEU get any kind of information from the Flap Position Indicator ? I ask because this is the only indication that will not match the actual configuration, which could lead the LE FLAPS TRANSIT light to remain lit.
I was told that the best way to find out if the TE flaps are really extending in this case is to look for the flap maneuvering speed on the speed tape... Is this really a good source of information ?
Please, if possible share some thoughts on this one !
Thanks :ok:
Recently I did a LOFT session and we had a TRANSFER BUS 2 OFF (B737NG).
After running the checklist for this non normal, we couldn't re-estabilish that part of the electrical system (not even using the APU).
Long story short, we did a non normal checklist for every single amber light that was on, but...
During flap extension, the LE FLAP TRANSIT LIGHT remained ON (and the Flap Position Indicator Didn't work). Would you have asked for this NNC ? Affirm, right ?
Now things get interesting...
The LE FLAP TRANSIT NNC gives you the following options:
1 -
*Trailing edge flaps are extended and the trailing edge flap position indication disagrees with the flap handle position... How can you be sure that the TE Flaps are extended and the flap handle agrees with it's position ?
Anyway, let's say that you decided to go on with the next options...
**Trailing edge flaps are extended and the trailing edge flap position indication agrees with the flap handle position... This one will lead you to a F15 landing, but this should be because of a disagreement between the LE devices and the TE flaps (which would cause the LE FLAPS TRANSIT light to stay ON). Knowing the system, you will obviously check the LE DEVICE position indicator on the overhead and discover that that the LE Flaps/Slats are positioned correctly and that will make you scratch your head.
Ok... Let's see the next option !
*** Trailing edge flaps are up... This one doesn't sound right either. Anyway, if you decide to take this path, the checklist will lead you nowhere after cycling the flap.
Sooooooo, what would you do ? Would you simply disregard the LE FLAP TRANSIT light ? Assuming it was caused by the TRANSFER BUSS OFF in first place would you go on with the operation checking the LE DEVICES position indicator as you extend the flaps?
Does the FSEU get any kind of information from the Flap Position Indicator ? I ask because this is the only indication that will not match the actual configuration, which could lead the LE FLAPS TRANSIT light to remain lit.
I was told that the best way to find out if the TE flaps are really extending in this case is to look for the flap maneuvering speed on the speed tape... Is this really a good source of information ?
Please, if possible share some thoughts on this one !
Thanks :ok: