Reduced engine taxi-out procedures
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I have been reading the Airport Briefing notes (10-1P2) for London-Heathrow EGLL and in the Taxi Procedures section it says "Whenever operationally and safely feasible, all ACFT are requested to shut down as many engines as possible while taxiing and holding on the ground". I was wondering if someone could explain this procedure.
Would you start engines 1 & 4 to taxi out and when and where would you start engines 2 & 3 ?Hope this isn't a daft question
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Definitely NOT a daft question. The 146 can be quite nippy when taxing around at light weight, but can be sluggish the closer you get towards max weight.
To answer your question I will start with the procedure for shutdown engines after landing as it may add context. The approved procedure is to start the APU during descent checks. It will then be ready for pack air changeover during approach. Not all airlines liked this and went with a slightly different procedure that could be less pilot friendly when you had a short taxi to stand and no GPU available.
With APU a/v the packs would be transferred from engine to apu during the landing check list taking care to also the select recirc switch to ON.
If engines 2 and 3 and their systems are serviceable: Once on the ground and at a safe and slow taxi speed the landing/taxi lights to taxi only, and at night consider use of the r/w exit lights. After vacating the r/w the airbrake and lift spoilers are selected IN and brakes, and when complete FLAPS UP, brakes change over to YELLOW. Once the after landing checklist is completed (PNF does this from check list and narrates as doing so - other pilot with be asked to confirm some selections such as hydraulic/geni serviceability before irrevocably action is taken.
Normal use Pack 1 on odd numbered days, Pack 2 even numbered days… minimum 2 minutes with engines below flight idle and air recirculation switched ON, hydraulics check as operating normally, confirm APU electric OK, gen 4 off/reset, gen 1 off/reset, (the question was then put from PNF… ”engines 1 and 4?” If answer was “shutdown” then engine 4 thrust lever to cut off, engine 1 thrust lever to cut off. Ensure each engine in turn runs down (consider pull fire handle if the rundown is abnormal). The slower taxi speed reduced brake use and excessive temps.
In the above condition, should the APU fail the a/c is still left with electrics from the sby generator (but then no nose wheel steering (no biggie) on the other hand, if the yellow system fails. No single hydraulic failure will leave you without brakes.
If your work for a penny pinching company that can’t spare 60 kg/hr of fuel for APU use, or the APU is u/s, once on ground and all the after landing checks complete, shut down gen 1/engine 1, OR gen 4/eng 4, but keep engines 2 and 3 running (hydraulic considerations as above). Preferably keep gen 4/engine 4 running as pax deplane though a jetty or keeping geni 4/engine 4 running for a deplane via steps with no GPU a/v.
Taxi out with minimum engine use. Depend if APU and APU geni a/v. If so, definitely engines 2 and 3 running, probably engine 1 and/ or 4 it’s a heavy aircraft.
Taxi out without APU/APU geni. As above, but at least one geni will be required to do a cross-start procedure on the other outboard engine at least 2 minutes before t/o AND when the a/c is stationary.
The above are the manufacturers approved procedures. Hope that helps?
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What a wonderful explanation for us all to learn from.
Thank you so much for this, there's a lot to learn from this aircraft.
Many thanks -
MB. Thank you. I wrote that on the Eurostar, hence a few typo mistakes, and now it’s too late to edit, but I hope it helps the JF146 community.