Hi,

 

In the SOP1 you have to have a 3 minute cool down before you can shut down the engine.? I cant seem to understand the logic in that. Should i really stay on taxiway and wait or at the gate? when Should i start the timer?

 

Thanks Michael Moe

Hi, 

 

The 3 minutes before shut down is a recommendation for GE engines that you can find in the FCOM v1 of the NGX (page NP 21.81 - PDF page 157)

The timer is started automatically by the FO after landing and they will advise you once they have elapsed.

 

Normally that cool down time is covered by the taxi in. But your taxi time is shorter than that, then you would wait for the 3 minutes to complete before shutting down the engines.

 

As a passenger, I have already experienced some delays in the engine shutting down after taxi at gate by the past and before reading the FCOM a couple of years ago, I didn't think of that actually.

It's amazing how that 3 minutes can just seem to take forever to go by...

Speaking of, I so far haven't heard the "ready for shutdown" call in SOP2. And I've even started the chrono myself after runway turnoff. The FO says something like "3 minutes" but that's about it...

 

 

In the SOP1 you have to have a 3 minute cool down before you can shut down the engine.? I cant seem to understand the logic in that. Should i really stay on taxiway and wait or at the gate? when Should i start the timer?

 

Just think about your body after a hard work out, you should do a cool down period of light work before stopping. The only time I've seen this become an issue was when I was flying the DC10. We would shut down the #2 engine after landing so we (Flight Engineer) would wait 3 minutes before turning the lever off. The engines receive a lot of temperature stress so they require some time for temps to stabilize through out the engine before shut down. I all ways visualize turbine blade stretch and imagine them settling at idle before shut down. Another big time limit is the 5 minute warm up before going higher above idle. Again, this allows the engine temps to stabilize and warm up fluids before going through temperature stress. In the DC10, this was an issue also since we delayed #2 start unless it was needed for heavy weight taxi. The engineer started the engine and hacked the clock to let you know when the 5 minute warm up for the #2 was complete. Most guys started it with enough time to ensure you meet the limit before takeoff. As others pointed out, in most airplanes this time is met during taxi. Even in the Gulfstream I've yet to meet a situation where I needed more time even with the shortest taxi.     

 

 

Speaking of, I so far haven't heard the "ready for shutdown" call in SOP2.

 

That's a bug in the manual.  Our SOP2 consultant pilot asked me to remove that callout from the program since they'd never say it in real life.