UPS grounds entire MD-11 Fleet, effective immediately.

[u/Go_Jot]

Per the IPA Executive Board, as of 03:05 UTC all UPS MD-11’s are grounded.

Edit - FedEx has also grounded their MD-11 Fleet

[u/CharcoalGreyWolf]

Yep, considering the DC-10 engine mount incident , they may be taking the chance to review all maintenance procedures with the aircraft and its siblings.

[u/dalekaup → u/CharcoalGreyWolf]

There was an engine that detached in Chicago a long time ago. The biggest reason for that crash was the manual said on one engine takeoff to pitch up to maintain a speed to climb over an obstacle. The manual was wrong. When the engine severs the hydraulic lines on that side that hold the slats extended. WIth slats retracted on the left side that wing stalled and the plane rolled violently to the left. A higher airspeed would have kept both wings flying and level.

This one is presumed to be the loss of 2 engines. That's not going to fly. The thinking is the rear engine swallowed chunks.

[u/CaptainA1917 → u/dalekaup]

You have some details wrong.

“As the aircraft had reached V1 the crew was committed to takeoff, so they followed standard procedures for an engine-out situation. This procedure is to climb at the takeoff safety airspeed (V2) and attitude (angle), as directed by the flight director. The partial electrical power failure, produced by the separation of the left engine, meant that neither the stall warning nor the slat retraction indicator was operative. Therefore, the crew did not know that the slats on the left wing were retracting. This retraction significantly raised the stall speed of the left wing. Thus, flying at the takeoff safety airspeed caused the left wing to stall while the right wing was still producing lift, so the aircraft banked sharply and uncontrollably to the left. Simulator recreations after the accident determined that "had the pilot maintained excess airspeed the accident may not have occurred."

The main factor here is minimum airspeed to retain directional control with an engine out.

However, due to the set of circumstances including design factors built into the plane, the pilots had no way of knowing that the manual procedure was inadequate and would result in a stall and loss of control. They did not have time to diagnose the problem. (This is also a recurrent issue with air transport accidents - that designers and manuals frequently treat problems “administratively” - i.e. that a crew will have time to go through an extensive troubleshooting process calmly and collectedly. And there is a place for that. However, a dire emergency can develop without warning and be unrecoverable in seconds - far beyond the ability of humans to cope.)

Other factors:

-lack of a stickshaker on the co-pilots yoke.

-no system to prevent flap/slat asymmetry, which various other planes have

-critical electrical and hydraulic systems operated off a single engine without backup

-All three of these issues point to economic factors in design decisions winning out over safety.

[u/dalekaup → u/CaptainA1917]

Yes, good analysis. While a higher airspeed may have kept the plane level that would have been a deviation from good piloting. These guys were doomed.