739 Tailskid

[mmrassi]

Hi,

Can anyone tell me how can we make sure about the tailskid on 739s are functioning properly during landing as there is no indication for this. Also the technical description for this part is very brief in our FCOM.

Failing to extend or retract impose several performance and speed limitations according to MEL but the first step which is identifying the tailskid problem remains unclear to me.

Thanks

[B737SFP]

Well, I might be wrong, but I believe that you will only find out that your tailskid is not working as it should during the walk around.

I know that the SFPs has something called SPSEU (Supplementary PSEU, or something close to that) which monitors the 2 position tailskid.

I'm guessing this one, but I think that a tailskid malfunction on this type would cause the PSEU light to come on as well.

:ok:

[mmrassi]

Good idea,
I will check the PSEU details

[mmrassi]

I just checked, SPSEU doesn't monitor tail skid mechanism!

[Skyjob]

Failing to extend or retract impose several performance and speed limitations according to MEL but the first step which is identifying the tailskid problem remains unclear to me.

The tailskid needs inspection if it has been activated, which in turn requires engineers to assess functional operability.

In pilot terms:
on walkaround you notice tailskid has ben activated
You notify engineers who will assess if tailskid has been activated or not
If engineers find it has been activated they may determine based on this that:

Tailskid is allowed to continue (within remaining limits) and be continued to be used without replacing the honeycomb internal structure, thus making good damage and/or accurately recording existing visual skid shoe damage so any subsequent tailskid activation can be noticed by crew;
tailskid needs replacing the honeycomb structure inside and a functional test is then required;



The latter requires MEL relief for despatch with penalties attached

[2006]

I believe mmrasi is on the correct path, the 900ER has a 2 positions tailskid, monitored by the SPSEU, electronic control, hydraulically actuated.
SPSEU light would light up if it does not work.
All of the info is from Cockpit companion, I haven't got acces to the official 900ER manuals, so can't check if it is in there.

[mmrassi]

The point is other sources say SPSEU monitors tailskid but our FCOM doesn't mention this and only says SPSEU monitors mid exit doors. Shall I consider this as a missing in our manual?

[B737SFP]

I hardly doubt you will find this kind of information on the FCOM.

But I can bet there's something on the AMM !

:ok:

[Yeelep]

Nothing directly monitors the tail skid position. The SPSEU takes discrete inputs and when certain conditions are met powers the solenoid in the tail skid actuator and extends or retracts it. There is no position feedback to the SPSEU.

The SPSEU light can be triggered by internal fault, discrete input faults or tail skid output overcurrent. So, if you get a SPSEU light and don't have the mid cabin doors, you can be sure the tailskid is inoperable.