B744 Engine run up
I had to do an engine run up today, to find out which engine was causing an oil smell in the cabin.
I assume Boeing gives guidance on allowable power settings with a given fuel load (or aircraft weight). But I don't have an AMM available. Anyone have one handy? We managed by the way. Just for a next time ;) |
You havent got a AMM??? ..... Unbelivable....Your maintaining aircraft yet you havent got access to to the relevant maintenance documentation legally required to do so , God help us
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I can't recall there being any values for stability in the AMM for this. I vaguely recall we had engine run documentation which provided this. Sorry, I've been out of the industry for a while.
However, the AMM did say that there should be sufficient fuel in the tanks by the end of the run to still cover the hydraulic fluid heat exchangers (900kg in outboard mains, 2450kg in inboard mains) Rgds NSEU |
Thanks NSEU.
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as the saying goes, never assume....!
71-00-00-862-031-D00 for minimum weight, thrust balancing and c of g limits! Table 204. Minimum Gross Weight for Engine Operation (747–400 With RB211 Engines 1 and 4) Minimum Gross Weight for Engine Operation (High Power)*[1] Power Level Test Engine Minimum Airplane Gross Weight*[2] Power Level for Opposite Engine*[3] Maximum C.G. (%M.A.C)*[4] Minimum Idle 350,000 lb (158,757 kg) 0.0 33 Approach Idle 350,000 lb (158,757 kg) 0.0 33 1.174 EPR 350,000 lb (158,757 kg) 0.0 27 1.174 EPR 530,000 lb (240,404 kg) 0.0 33 1.174 EPR 350,000 lb (158,757 kg) 1.174 EPR 33 1.358 EPR 350,000 lb (158,757 kg) 0.0 10 1.358 EPR 750,000 lb (340,194 kg) 0.0 28.5 1.358 EPR 350,000 lb (158,757 kg) 1.174 EPR 31 1.358 EPR 405,000 lb (183,705 kg) 1.174 EPR 33 1.6 EPR 350,000 lb (158,757 kg) 1.174 EPR 11 1.6 EPR 750,000 lb (340,194 kg) 1.174 EPR 28 :eek: |
Well, that was a surprise, Spanners :P
I assume the higher fuel weights are to cover the wider range of CGs? Perhaps if the aircraft is loaded for a flight, has a large aft CG, and has a last minute engine problem? |
I agree with Brigantee
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Mariner and the AMM
For those of you bagging Mariner, he is a pilot, not a LAME and I suspect he was requested to run engines either individually, or individually supply the pneumatic system, to determine which engine his aircraft may have been getting contaminated bleed air from.
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Still sounds dodgy...
What if he hadn't "managed"? Who was downstairs? Where were the tests being carried out? Why wasn't engineering doing the tests? |
I was taxi/runup qualified on 747 100,200 and 300 with Rolls,Pratt and GE engines.during initial and recurrent training over the years I was never instructed on EPR or N1 limits with regard to aircraft gross weight - is this something that has been made applicable to 400 series only?
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is this something that has been made applicable to 400 series only? https://www.flightglobal.com/news/ar...340-60-319969/ |
i do not see any relevance to gross weight - the problem seemed to be lack of chocks and incompetence.
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Originally Posted by Old Fella
(Post 9506172)
For those of you bagging Mariner, he is a pilot, not a LAME and I suspect he was requested to run engines either individually, or individually supply the pneumatic system, to determine which engine his aircraft may have been getting contaminated bleed air from.
And thanks Spannersatcx, that was helpfull. 👍 Looking back, we stayed well within those parameters, even though we had PW4000 engines. And we did find the culprit, so the mission was succesfull. |
Table 202. Minimum Gross Weight for Engine Operation (747–400 With PW4000 Engines 1 and 4)
Minimum Gross Weight for Engine Operation (High Power)*[1] Power Level Test Engine Minimum Airplane Gross Weight*[2] Power Level for Opposite Engine*[3] Maximum C.G. (%M.A.C)*[4] 747–400B EPR Minimum Idle 350,000 lb (158,757 kg) 0.0 33 Approach Idle 350,000 lb (158,757 kg) 0.0 33 1.088 EPR 350,000 lb (158,757 kg) 0.0 27 1.088 EPR 530,000 lb (240,404 kg) 0.0 33 1.088 EPR 350,000 lb (158,757 kg) 1.088 EPR 33 1.207 EPR 350,000 lb (158,757 kg) 0.0 10 1.207 EPR 750,000 lb (340,194 kg) 0.0 28 1.207 EPR 350,000 lb (158,757 kg) 1.088 EPR 31 1.207 EPR 405,000 lb (183,705 kg) 1.088 EPR 33 1.6 EPR 550,000 lb (249,476 kg) 1.088 EPR 14 1.6 EPR 750,000 lb (340,194 kg) 1.088 EPR 22 |
Being a quad, there is less concern with a 747 jumping the chocks during a high power run than with the big twins like the 767 and 777. Rather, the primary concern is with the side forces on the nose wheels.
Many years ago, I was in the flight deck on a 767 during high power trim runs when the nose gear moved sideways :eek: - I was mildly amazed at how quickly the engine run guy had the throttles at idle :E. There had been a hydraulic fluid spill near the nose and the tires slipped on the hydraulic fluid. The ground crew reported the nose had moved about six inches - those of us in the flight deck thought it had been more like six feet :mad:. |
Just a suggestion but the oil consumption run would be a way of determining this fault, of course running up to 4 engines at power can be impractical and costly so some idea from oil uplifts should narrow the field, older cold air units with oil sumps can produce this problem and the APU has to be eliminated but usually this smell occurs during take off and early climb out. Even the quad B744 will need an opposite balancing engine when power is applied.
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Originally Posted by tdracer
(Post 9506873)
Being a quad, there is less concern with a 747 jumping the chocks during a high power run than with the big twins like the 767 and 777. Rather, the primary concern is with the side forces on the nose wheels.
Many years ago, I was in the flight deck on a 767 during high power trim runs when the nose gear moved sideways :eek: - I was mildly amazed at how quickly the engine run guy had the throttles at idle :E. There had been a hydraulic fluid spill near the nose and the tires slipped on the hydraulic fluid. The ground crew reported the nose had moved about six inches - those of us in the flight deck thought it had been more like six feet :mad:. |
Originally Posted by aeromech3
(Post 9506888)
Just a suggestion but the oil consumption run would be a way of determining this fault, of course running up to 4 engines at power can be impractical and costly so some idea from oil uplifts should narrow the field, older cold air units with oil sumps can produce this problem and the APU has to be eliminated but usually this smell occurs during take off and early climb out. Even the quad B744 will need an opposite balancing engine when power is applied.
And the oil smell actually occured during descent and taxi in on the previous sector, which was a bit puzzling. Oil leakage is a known problem on the P&W 4000 series, and there are a number of SB's about oil leakage caused by carbon seal wear and coking. The engine was subsequently replaced, so the complaint has been closed. It had been due for replacement at the end of the month anyway. |
In fact, it has something called Thrust Control Malfunction Protection. It's not really there for ground runs (though it would still be of benefit if an engine ran away uncontrolled) - it's there for takeoff or landing where an uncontrollable high thrust event could result in a high speed runway departure. |
Originally Posted by tdracer
here had been a hydraulic fluid spill near the nose and the tires slipped on the hydraulic fluid. The ground crew reported the nose had moved about six inches - those of us in the flight deck thought it had been more like six feet .
Originally Posted by tdracer
It's not really there for ground runs (though it would still be of benefit if an engine ran away uncontrolled) - it's there for takeoff or landing where an uncontrollable high thrust event could result in a high speed runway departure.
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