EICAS "ENG X AUTOSTART" in flight? CF6

[paojack]

Dear 744 crews, I hope all is doing well.
Most recent revision on ENG X AUTOSTART QRH (V.76), the condition statement changed from "During a ground start, one of the following conditions occurs" to "One of these occurs", to account for the possibility of this message showing "in-flight".
the the conditions are:
1. Autostart did not start the engine.
2. Fuel control switch is in RUN at low engine RPM with the autostart switch off.
I stand to be corrected. but the only way I can think of when this message occurs in flight is during an in-flight Engine Start after engine failure, with condition 2 above (autostart SW off + N2 rpm below X-BLD magenta line + fuel control switch to RUN). but somehow I couldn't duplicate this in aerowinx. any thoughts?

P.J

[Hardy Heinlin]

Hi P.J.,

the CF6 autostart will make up to 3 attempts when on the ground; it will make an infinite number of attempts when in flight.

When you monitor the autostart program text on the Analysis page, you'll see the text will say something like "Attempt 3/3, ignition & fuel on, reduced by 7%" when on the ground. In flight it will just say: "Next attempt, ignition & fuel on".

So, in flight, there'll be no "last attempt", thus there'll be no "I-give-up" EICAS message.

PSX has this demo situ file for a no-windmilling inflight start, which makes 3 hot starts and thusly requires 4 attempts (more than the usual 3-attempt limit on the ground):

Training 614 - Autostart air - starter assisted - CF6.situ


|-|ardy

[paojack]

Hi Hardy,

Thanks for the reply, that's also my understanding toward the system, unlimited attempt inflight, never give up means no ENG X AUTOSTART msg possible.
That is also the reason I ask  this question after Boeing revise their QRH stating the possibility of this message showing "in-flight"... just curious what the scenario might be.

P.J

[paojack]

Also, during a ground manual start, procedure mandate N2 RPM above minimum fuel on indicator (magenta line) before switching FUEL CONTROL SW to RUN, otherwise self induced hot/hung start might possible. I was wondering if the QRH statement
"Fuel control switch is in RUN at low engine RPM with the autostart switch off." actually act as some kind of reminder, when switching FUEL CONTROL SW to RUN when N2 is below magenta, this msg would appear? as an ALERT?

P.J

[Hardy Heinlin]

Possibly. I don't know of any EICAS software updates in this context ...