pylon inspections
12-01-2025 | 02:11 PM
#81
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Joined: Apr 2011
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This is not the first time a DC / MD had a wing engine cause damage to other motors.
https://asn.flightsafety.org/reports...C10_N39081.pdf
https://asn.flightsafety.org/reports...C10_N39081.pdf
12-11-2025 | 03:21 PM
#83
Gets Weekends Off
Joined: Apr 2011
Posts: 3,537
Likes: 146
The preliminary report clearly shows the #1 engine separating at the pylon, exiting the aircraft ahead of the wing, then over the wing, then over the fuselage, past the #2 engine. The #1 engine and pylon was found on the right side of the runway. That's a bit more than debris fouling the #2 engine.
#2 has always been the most vulnerable in several respects; it needs pump pressure to feed, rather than gravity feed like the wing engines. No fuselage contamination, not just wings, to ensure nothing goes in the #2, etc.
The MD11 isn't the first aircraft to have a top-mounted third engine; the DC10, L1011, and 727 shared that, as do certain of the Dassault Falcon series. Numerous aircraft have used aft mounted engines, with contamination from nose, nosewheel, etc, being a potential issue. Even the MD87 airtanker was flaming out engines due to retardant contamination while righting fires. Stuff going in engines at the back of the airplane happens, from nosecone ice to snow and ice on top of the fuselage, to water on the runway off nosewheel chines.
None of that is really the issue. Fatigue and attach point failure is the focus presently, and whether it's a flock of birds or the ultra-rare circumstance of an engine flying forward of and over the wing...these are extremely rare things that do not speak to the inherent airframe engine configuration, but to a specific, localized problem which may require a re-design, inspection, inspection and replacement, design material change, component life-limit, or other alternate means of compliance.
Slat retraction on the DC10 is irrelevant here. This wasn't a DC10.
UPS, Western Global, and FedEx are going to have to decide if the cost of the repair, whatever it is finally determined to be, is justified to return the aircraft to service. You can be assured that a reduced inspection interval will be appended initially to ensure the part is getting inspected and tracked and evaluated for further fatigue or wear. It will come down to whether the repair is economically viable, as it does with all aircraft. Sometimes, events occur in which the cost to return the aircraft to service (and keep it in service) isn't. justified by the economic benefit of the return. Time will tell.
#2 has always been the most vulnerable in several respects; it needs pump pressure to feed, rather than gravity feed like the wing engines. No fuselage contamination, not just wings, to ensure nothing goes in the #2, etc.
The MD11 isn't the first aircraft to have a top-mounted third engine; the DC10, L1011, and 727 shared that, as do certain of the Dassault Falcon series. Numerous aircraft have used aft mounted engines, with contamination from nose, nosewheel, etc, being a potential issue. Even the MD87 airtanker was flaming out engines due to retardant contamination while righting fires. Stuff going in engines at the back of the airplane happens, from nosecone ice to snow and ice on top of the fuselage, to water on the runway off nosewheel chines.
None of that is really the issue. Fatigue and attach point failure is the focus presently, and whether it's a flock of birds or the ultra-rare circumstance of an engine flying forward of and over the wing...these are extremely rare things that do not speak to the inherent airframe engine configuration, but to a specific, localized problem which may require a re-design, inspection, inspection and replacement, design material change, component life-limit, or other alternate means of compliance.
Slat retraction on the DC10 is irrelevant here. This wasn't a DC10.
UPS, Western Global, and FedEx are going to have to decide if the cost of the repair, whatever it is finally determined to be, is justified to return the aircraft to service. You can be assured that a reduced inspection interval will be appended initially to ensure the part is getting inspected and tracked and evaluated for further fatigue or wear. It will come down to whether the repair is economically viable, as it does with all aircraft. Sometimes, events occur in which the cost to return the aircraft to service (and keep it in service) isn't. justified by the economic benefit of the return. Time will tell.
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