(1) In THE PMDG 737, Assuming normal engine start, up to point where fuel value is opened. If you fail to open the fuel valve, why does the EGT still JUMP UP to about 300 degrees, and when the engine fails to start, JUMP back to no display ? What is producing that heat, if there is no fuel --- or is that a min value that displays to confirm that EGT is being measured ?? Maybe a related issue.HOT START -- (incorrect start simulation) (2) In the REAL WORLD 737, If Fuel valve is turned on BEFORE attempting to start engine, then, when that fuel ignites, with n1 very low, will that generate a HOT Start, or are there protections in place to prevent this. (3) In a REAL WORLD 737, is it possible to start the engines, if all the electrical fuel pumps are off. Can the mechanical pump provide enough fuel pressure at startup N1, for starting ? Geoff

Just to add, can we actually damage the engine during start? Lj. Prodanovic

where your engines still warm after the last flight?

where your engines still warm after the last flight?

No, the EGT temperature indication with Fuel cutoff, was obtained during a Cold Start from dark. If there is anything in the massive Manal about this being some form of sensor diagnostic system, I must have missed it.It would make sense to have some indication that the EFT sensor was working correctly, before trying to start the engine. Geoff

(1) In THE PMDG 737, Assuming normal engine start, up to point where fuel value is opened. If you fail to open the fuel valve, why does the EGT still JUMP UP to about 300 degrees, and when the engine fails to start, JUMP back to no display ? What is producing that heat, if there is no fuel --- or is that a min value that displays to confirm that EGT is being measured ?? Maybe a related issue.HOT START -- (incorrect start simulation) (2) In the REAL WORLD 737, If Fuel valve is turned on BEFORE attempting to start engine, then, when that fuel ignites, with n1 very low, will that generate a HOT Start, or are there protections in place to prevent this. (3) In a REAL WORLD 737, is it possible to start the engines, if all the electrical fuel pumps are off. Can the mechanical pump provide enough fuel pressure at startup N1, for starting ? Geoff

(1) ? (2) Apparently this isn't modeled. (3) YES I'm sure it crossed your mind that this is a simulation, and some things may not be modeled.

Just to add, can we actually damage the engine during start? Lj. Prodanovic

If you pump fuel into the engine, and the igniters are on, and turbine is not up to Engine Start N1, you can get very high temperatures as the Jet Fuel burns, and without the airflow, you can literally MELT down the turbine engine ( HOT START ).... Very EXPENSIVE mistake !!.

My question was directed to find out if the 737 has any automatic interlock systems to prevent this from happening. Compressor stalls are another fact of life under ceratin condition, and can especially be quite dramatic at night.

The lack of any "Hot Start" or "Compressor Stall" effects would tend to suggest that these are not simulated on the PMDG 737 ? Geoff

Interesting.

Re #2:

On the subject of engine starts - it's actually extremely difficult to screw up a start on a modern jet engine. We tried a bunch of things in the real NG sim trying to screw up the starts to see if this is something we should model and you basically can't do it. Our pilot advisors have said the same - most have never seen any trouble at all with a start.