Dash 8-300Q questions

[Ethiopia]

Dear colleagues,

I recently went through a Dash 8 type rating course and now that I am reviewing all the training stuff, the following doubts arised:

- During start-up procedure I was told to time for oil pressure indication. I realised that, at least in the simulator, that the average time for first gauge indication is between 5 and 10 secs, but I couldn´t find in the limitations chapter an specific amount of time after which a shutdown must be carried out. What´s your company policy/procedure? Is it company´s own limitation or the one provided by Bombardier?

- Heard of some airlines engaging (arming) the autofeather system on final approach in anticipation for a go-around and a subsequent engine failure. Is this true? Approved by the manufacturer? Pros and cons?.

Tnx!

Ethiopia

[Gooneyone]

Never saw anything about a time limit for oil pressure during start in the AFM. We check oil pressure between 55 - 65 PSI and Warning Light extinguished after starter disengage and engine stabilised.
Also, never heard of autofeather being armed on final approach. This would be in violation of the AFM and introduces the possibility of an unscheduled feather in the event of a go-around - especially if one engine spools up quicker than the other.
Stick to the AFM - they used test pilots, we carry passengers.

[Ethiopia]

No doubt about sticking to the AFM, of course! Can you briefly outline an engine start sequence and what indications you look for?.

Thank you.

[Gooneyone]

Briefly, starter selected, look for 10-19%Nh, Condition lever to start/feather, fuel flow increases to approx 100pph.
ITT starts to rise within 10 secs. of fuel on. ITT continues to rise, look for rising Nh, Nl, Np. Oil pressure should start to rise. At 63%Nh, listen for "click" as start selector cancels and switch returns to off position. Engine should stabilise at approx 73%Nh with oil pressure between 55-65 psi and all other parameters stable.
Hope this helps.

[Flying Farmer]

Are you flying for Air South West ?

PM me if you like.

[Alpine Flyer]

It's been a long time but I recall that waiting for the oil PX to rise before fuel-on was not a good idea as some of the engine bearings are sealed with bleed air which is not available at that time. If you crank too long oil gets throught the unpressurized bearings.

Therefore we only looked for oil PX rising after fuel on.

As for the autofeather, at our alpine company we used to arm it during approach in the early days but that was later rescinded due to the concerns written above (i.e. power application during approach arming the system and uneven power reduction causing an unwanted feather)

[Gooneyone]

Never seen the oil pressure rise before fuel on. Usually see some movement by the time the Nh gets to about 30 - 40% - but that's in the tropics where the oil temp never gets below about 25C even after the a/c parked overnight.