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Allan Burek

744 Autostart Procedures

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Hello All:As a former flight mechanic on the real 744F as well as an avid fan of PMDGs superior product, there is an error that I have noticed that I feel could use some required attention. As a user of FS9, and having been employed by airlines for the last 10 years, I feel that realism is as big of a part of my FS experience as any good payware A/C. In several different references::-747 AOM page 5-12-PMDG Tutorial Checklists-many posts on this forum...there is an error with the autostart procedure called out. I have seen instances of where the procedure was called out as follows:-fuel control switch to run-start switch out.This is a recipe for disaster. It can cause hot starts, stalls (deadly on GE powerplants) and who know what else. I know this is a sim, but allow me to quote the GE aircraft maintenance manual:

(6)Start engine (ground low pressure or APU air source) (Fig. 207 and 208).(a)Observe power plant operating limitations (Ref par. 3.).(b)On P5 pilots' overhead panel, check the following as specified:1)APU VALVE switch - off if ground low pressure air source is being used for engine start, ON if APU air source is being used for engine start2)L ISLN VALVE switch - open to start engine 1 or 2, closed to start engine 3 or 43)R ISLN VALVE switch - closed to start engine 1 or 2, open to start engine 3 or 4©On primary EICAS, check that left or right DUCT PRESS is a minimum of 35.(d)If using autostart, perform the following:1)Position AUTOSTART switch to ON2)Pull applicable START switch out.3)CAUTION:DO NOT MANUALLY TERMINATE START (EXCEPT IN EMERGENCY) UNTIL 50 %N2 RPM IS REACHED. TERMINATION OF START PRIOR TO REACHING 50 %N2 RPM CAN CAUSE HOT STARTS WITH RESULTING ENGINE DAMAGE.Position applicable engine FUEL CONTROL SWITCH to RUN and check that START switch illuminates.NOTE:When FUEL CONTROL switch is positioned to RUN, the starter will engage and begin to rotate engine and EICAS will display N2, N1, and the correct EGT values.4)Check EICAS for indications as specified as engine lights up and accelerates toward idle.NOTE:Using autostart, the system will automatically terminate the start if the engine fails to light up, if the engine stalls, or if there is an overtemperature condition. In the case of a failure to light up, the autostart system will automatically dry motor the engine following the start termination and then initiate a second start attempt.a)N1 and N2 increase (N1 rpm should be approximately 6% when N2 rpm is 30% during start cycle and N1 rotation must be confirmed, by ground personnel, within 30 seconds of operation at minimum idle %N2 rpm).b)The engine lightup (EGT rise) must occur within 25 seconds or less after the FUEL CONTROL switch is put in the RUN position.NOTE:In usual conditions it will take approximately 5 seconds to reach 15% N2 and then lightup will occur within 20 seconds after reaching 15% N2.c)Fuel flow is approximately 250-300 KGPH at lightup.d)Engine oil pressure indication (Fig. 205).e)ENG (1, 2, 3, or 4) OIL PRESS EICAS advisory message disappears as oil pressure increases past 15 psi.f)HYD PRESS ENG (1, 2, 3, or 4) EICAS advisory message disappears as hydraulic pressure increases past 1400 psi.5)Check that START switch releases to off position and light extinguishes when N2 rpm reaches 50%. Check that STARTER CUTOUT (1, 2, 3, or 4) EICAS caution message does not appear.a)If START switch does not release at 50% N2, manually press switch to off position.:(CAUTION:IF "STARTER CUTOUT (1, 2, 3, OR 4)" EICAS CAUTION MESSAGE APPEARS AFTER "START" SWITCH RELEASES TO OFF POSITION, YOU MUST DO THE STEPS THAT FOLLOW TO SHUT DOWN THE ENGINE TO PREVENT STARTER DAMAGE.If STARTER CUTOUT (1, 2, 3, or 4) EICAS caution message appears with START switch in the off position: 1 Push the BLEED switch to the OFF position. 2 Stop for a 30 second period. 3 Then move the FUEL CONTROL switch to CUTOFF. 4 Troubleshoot the cause of the message (FIM 71-EICAS Messages).6)Allow engine to accelerate to idle.
Im fairly sure that this is standard across all 3 engine types. I hope this sheds light for some who may have seen 2 or 3 different procedures, and I welcome all comments. Thanks for allowing me to rant! PMDG, great work as always.Allan BurekCoordinator, Aircraft Maintenance OperationsGlobe Cargo Virtual Airways

Allan Burek
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Great info Allan, thanks! I only have the SOP for PW engines.Rob


Rob Prest

 

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Rob,What do the PW SOPs state in regard to the autostart process? I know people who have worked the 744 at NW and UA and both airlines didnt have autostart.Allan BurekCoordinator, Aircraft Maintenance OperationsGlobe Cargo Virtual Airways


Allan Burek
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Not sure about the pax aircraft but I have the 744F SOP for SIA Cargo and they all have autostart. Bit hungover right now :) but I will post back with the info.Rob


Rob Prest

 

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Based on my AOM (for RR) and the ITVV video (GE) the process is the same as you assert: Pull switch, then set fuel cutoff switch to RUN. As I mentioned in another post the sim allows you to do it either way without consequence, but I prefer regimented procedural accuracy so I do it as per my AOM!


Mark Adeane - NZWN
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This has been pointed out to PMDG before. The correct method is start switches first then fuel switches. I am sure Capt Randanzzo could attest to that now he is type rated.


Cheers

Steve Hall

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So the real issue is with the starter and then cutoff sequence??Thanks for the detailed information!! I'll modify my SOP to reflect it. :)Best regards,Robin.

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"This is a recipe for disaster. It can cause hot starts, stalls (deadly on GE powerplants) and who know what else. "Not true! Autostart controls the starting sequence perfectly, irrespective of whether you select the start switch or fuel cutoff lever first.Although (IMHO) it is a good idea to use the same sequence as a manual start, you can cause just as much damage to engines by forgetting to select Autostart and then pulling the two switches within seconds of each other. A year or two ago, Thai Airways cooked 3 engines by forgetting to reselect Autostart after predeparture maintenance (as far as I know, their procedures are the same as yours).AFAIK, there is an airline which uses PMDG's procedure for Autostart, therefore, it is perfectly valid. Some airlines do love to do things differently ;)Cheers.Q> Ян (747 Engineer for 33 years)

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I'd like to raise an issue...I can have both isolation valves open, one pack running (on APU or external air - makes no difference), and a duct pressure of 22 psi, yet I can perform a multi-engine start in this configuration without issue.Is this even possible?EDIT: APU supplying power, external air.Pack 2: Duct pressure drops from 22 psi to 19.Switching either Pack 1 or Pack 3 on INCREASES duct pressure to 25 psi.With Pack 2 running only, and duct pressure at 19 psi, with both ISOL VALVES open, I can start two engines.Best regards,Robin.

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"Switching either Pack 1 or Pack 3 on INCREASES duct pressure to 25 psi.With Pack 2 running only, and duct pressure at 19 psi, with both ISOL VALVES open, I can start two engines."Unlike older type 747 APU's, the 744 APU increases its output to compensate for demand, hence the increase in duct pressure with extra pack load. In theory, maximum output should occur during engine start (Why waste fuel when you don't need the pressure). However, there are occasions when APU's don't increase output fast enough to keep the pressure from dropping due to large demands (especially on aircraft with APU's which are getting older). Since this is not unusual, PMDG did their best to model a typical APU.If PMDG had modelled a theoretically perfect/brand new APU, I'm sure they'd get comments from real world pilots/engineers saying that their APU didn't behave like this ;)Cheers.Q> Ян

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The hot starts ,etc. can be caused in the case if the autostart being off. I know were supposed to follow the checklist and I suppose I should have been clearer. Thanks for bringing it to my attention.Allan BurekCoordinator, Aircraft Maintenance OperationsGlobe Cargo Virtual Airlines


Allan Burek
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