CSD Disconnect...

[aviatorhi]

I recently came accross an oppinion that prior to an inflight engine shutdown (whatever the reason) it would behoove one to disconnect the CSD for that engine. The reason given was that at windmill speeds the CSD won't disconnect if you need to disconnect it. I don't see a reason to do so from a technical standpoint since I don't see why I would ever need to do a CSD disconnect on an engine that's shut down. But maybe I'm missing something.

[411A]

No, it is not necessary to disconnect the CSD/IDG prior to engine shutdown.

[yotty]

On the CMF56-3C it's possible to disconnect the CSD while it's stationary! I've been called out many times to reconnect on the taxiway following the switch being operated instead of the battery sw by mistake. It might be prudent to keep the CSD connected, depending on type and attitude/altitude I would imagine it would keep generating. BA 747 never went dark when it flew into the volcano plume. :ok:

[TopBunk]

aviatorhi

... but surely if it were a prerequisite of the engine shutdown procedure it would be the first item on the QRH procedure?

Don't look to invent new procedures, follow the manufacturers policy as approved by the regulatory authorities.

[411A]

...I would imagine it would keep generating.
Hardly likely, as it would be in a severely underspeed condition.

BA 747 never went dark when it flew into the volcano plume.
Ships battery power remains, even if all engines flamed out.

[galaxy flyer]

It would have to windmill at 8000 rpm in the accessory case, rather doubtful. But, as I learned on the Concorde thread, it could maintain AC power by windmilling down to M 1.5, so it's possible but not in a subsonic plane

GF

[aviatorhi]

Thanks for the input, I was scratching my head as to what the reasoning behind the statement was...

Don't look to invent new procedures, follow the manufacturers policy as approved by the regulatory authorities

Sure maybe on aircraft designed after 1970, but a lot of the 1st and 2nd generation airliners, which I fly, are tempermental machines that involve more black magic in their operation than they involve the "approved manuals". Most operators manuals are actually quite simplified and in disagreement with the manufacturers manuals these days. There's also a lot of crew discrection built into (at least our) procedures.

[411A]

Most operators manuals are actually quite simplified and in disagreement with the manufacturers manuals these days.

A big mistake, in my considered opinion.
When I joined a small southeast asian airline (now, very large and successful)in 1977 on the B707, the airline in question adopted the manufacturers procedures...to the letter.
IE: Boeing AFM with the airlines logo on the front cover.
Many airlines (including ours) did the same with the L1011.

The KISS principle...works good, lasts a long time.
It is when 'some' airlines try to adopt similar procedures across all aircraft fleets with different manufacturers...that is where the problems begin.
Sometimes, rather big problems.

NB.
However, there can be 'improvements'.
But, they generally do NOT originate within the fleet manager/chief pilots office.
Example.
I respectfully suggested to the afore mentioned airline that they should investigate a reduced landing flap procedure to not only reduce noise, but to also reduce fuel consumption.
The Fleet Manager stated...'Show me just where in the Boeing procedures that this is allowed, and the benefits achieved.'
I promptly did so, and the reduced landing flap procedures were adopted, with regard to dry runways (only), of sufficient length.

IE: the devil is IN the details.