China Airlines 747F damages two engines at ORD
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If you watch the beginning of the video from the plow, it starts before the video above. The aircraft was barely moving, going at 5 KTS max (appropriate taxi speed), then it abruptly and sharpy turns about 60° to the left and accelerates straight towards the ramp. Not the type of spin and acceleration that I would associate with just losing traction at idle thrust. It looked and sounded like he gave it some thrust, and the thrust reversers aren't deployed. You can see that in the above video. Maybe he hit the TOGA switches by drooping his fingers over the thrust levers and it spun and launched him before he knew what was happening. Maybe he got too far to the right and just panic reacted by cranking the nosewheel to the left and goosing it. I'm sure the two in the cockpit know what happened. Can't wait for the investigation report on that one. BTW, the original video is not sped up. He was moving that fast.
List price is around $10M. However insurance would only pay for repair or replacement with engines having equivalent hours/cycles, whichever lower. These will probably be repaired, I would expect damage to be limited to fan & cowling.
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That's probably true for #2, but unless I'm mistaken it looks at one point in the video like #1 ingested and spat out bits of a container.
Probably both injected bits and pieces, but with a bit of luck these would be shredded and ejected in the bypass duct (per design), should not enter the core. If the core did ingest something, that indeed pushes the repair bill up a few notches.
A boroscope inspection will reveal if there is any damage to the engine core. If yes, indeed a full teardown. Regardless of the core, the fan disk will need extensive testing to check for any signs of overstress, if the test is positive it will need to be discarded, such damage is non-repairable. Any visible damage on the fan blades and especially the cowling is the least of the worries here.
Last edited by andrasz; 3rd Feb 2022 at 17:17.
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I suspect that the video is showing the event very "speeded up". The time between the two flashes of the top and bottom red flashing beacons is 12.3 seconds in the video, where other videos I find of B747 beacons appear to show the beacon flash period to be just over a second. So the video is maybe ten times actual speed?
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If the video was speeded up the interval between flashes would reduce not increase.
Most likely, it's the frame rate of the video - strobe duration is very brief, so if the frame rate is slow it's going to miss many of the strobe flashes.
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A boroscope inspection will reveal if there is any damage to the engine core. If yes, indeed a full teardown. Regardless of the core, the fan disk will need extensive testing to check for any signs of overstress, if the test is positive it will need to be discarded, such damage is non-repairable. Any visible damage on the fan blades and especially the cowling is the least of the worries here.
Given the unusual circumstances of this accident, IMO, the two engines will be completely torn down and inspected, replacing any suspected or damaged parts. A simple boroscope inspection isn't good enough. There is much potential liability to be avoided by doing a complete teardown, internal inspection and subsequent engine testing before a return to service...