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HAWK21M
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Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 9:25 pm

How do you avoid Windmilling of Engines when Aircraft is parked apart from Relocating the Aircraft to a Different Direction to reduce the Windmill or Use Engine Blankings.
The reason is eg on a B732 ie P&W JT8D if the Engines are windmilling for more than 60 minutes with less than 10 psi oil pressure after shutdown then it
shall be sent to overhaul for bearing inspection with particular attention to No. 2, 3,4, and 5 bearings.
This can prove expensive.
regds
HAWK
I may not win often, but I damn well never lose!!! ;)
 
FredT
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RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 9:43 pm

Tie the fan down, if that's the only part windmilling, or install engine covers?

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
air2gxs
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RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 10:38 pm

"The reason is eg on a B732 ie P&W JT8D if the Engines are windmilling for more than 60 minutes with less than 10 psi oil pressure after shutdown then it
shall be sent to overhaul for bearing inspection with particular attention to No. 2, 3,4, and 5 bearings."

Where did that come from??

Windmilling is not normally an issue. The engine isn't turning fast enough to cause the bearings to heat up, which in turns means they do not require lubrication. I suspect the statement above concerns a windmilling engine in flight, i.e. after an IFSD event.
 
avioniker
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RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 11:26 pm

If it's a problem then deploy the reversers like many other companies do...
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
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HAWK21M
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RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 11:29 pm

The Statement comes from the B732 Maintenance Manual.I dont recollect the page at the moment.
This is concerned with Maintenance not IFSD caused windmilling.
regds
HAWK
I may not win often, but I damn well never lose!!! ;)
 
FredT
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Joined: Thu Feb 07, 2002 9:51 pm

RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 11:32 pm

Even though they are moving slow, windmilling with dry bearings is indeed a problem to be vary of. All kinds of rubbing and grinding going on that the engines weren’t designed for.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
SlamClick
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RE: Windmilling Of Engines While Aircraft Parked

Mon Jan 19, 2004 11:40 pm

I am pretty sure the "windmilling" referred to in that manual means windmilling due to being shut down in flight. I have never heard of any operator making allowance for the wind turning the engines on the ramp.

That said, I know there are operators who put dog dish engine covers in place when leaving a plane overnight.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
air2gxs
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RE: Windmilling Of Engines While Aircraft Parked

Tue Jan 20, 2004 4:10 am

Our procrdures dictate engine covers only when the conditions warrant, i.e. blowing snow, ice, freezing rain not high wind. I just looked through our B767 & B757 AMM and could only come up with conditional inspections on windmilling engines in flight due to IFSD with oil pressure below 10 psi. Nothing about windmilling on ground.

Granted if we were turned into the wind or against the wind in a 30 or 40 knot + gale I would be concerned and probably deploy the reversers, but for the most part we deploy reversers to quiet the area we are working in.

Sorry about the following formatting:

From the B757 AMM:
Engine Windmilling Inspection A. General CAUTION:YOU MUST EXAMINE AND CORRECT THE MALFUNCTIONS OF THE ENGINE, WHICH CAUSE AN ENGINE SHUTDOWN IN FLIGHT, BEFORE THE SUBSEQUENT ENGINE OPERATION. (1) You must do the Engine Windmilling Inspection before the subsequent operation if the engine turned freely because of a shutdown in flight. NOTE: Write the conditions of operation before and after the engine turned freely. The information is necessary to classify the type of windmill and to compare for the subsequent time the engine windmills.


From the A300 AMM:

Prior to further operation, engines which have windmilled as result of in flight shutdown (IFS) must be inspected in accordance with the following: NOTE : Engine operating conditions recorded prior to and after shutdown and during windmilling are required for this inspection and should be retained for future reference. (1)If there was continuous positive oil pressure following engine shutdown and during windmilling, (an indication pump was producing pressure, i.e., pump did not fail, oil lines did not fracture, or rotor/gearbox did not seize, etc) accomplish the following checks: NOTE : During windmilling, oil pressure indications may be low or unreadable, (Below 40 PSIG, 2.76 BARS) which is permissible if oil temperature conditions are within limits. (Ref. 71-00-00, P. Block 201).

I don't have the B727 AMM handy at this time but I've worked on them and the B747 for years. Ground windmilling is not an issue.

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