Another potential Alaska Airlines MD-80 event?

Incident: Allegiant MD83 at Las Vegas on Aug 17th 2015, rejected takeoff due to premature rotation

 

Allegiant Air's Pilots Warn Passengers of Safety Concerns ? Skift

 

I've always hated getting on the MD-80 series jets after that Alaska Airline crash in 2000. The news reports and detailed articles about how the lone jackscrew operated the control surface was way too graphic for me to want to ever get on another one. I have, but I didn't like it.

 

How did it or could it become disconnected? That's scary.

 

Read about that Alaska Airlines MD80 crash off CA. Elevator jackscrew jammed twice causing a nosedive each time. Crew barely recovered from the first one before it jammed again, rolling the plane over before nose diving into the Pacific. Pure terror

The culprit: Poor maintenance.

 

Actually, the threads stripped out because of the wrong grease being used over a period of time, allowing the STABILIZER to move uncommanded and reacting to elevator inputs which yielded the opposite results desired (nose up/ nose down inputs reversed). (NTSB Report)
The wrong grease dried out and the threads peeled off the jack shaft like speghetti. (I saw the pictures).

The flight crew could hear it slamming back and forth in the tail of the airplane.

 

In the case of the Las Vegas aircraft, an actuator became disconnected from an ELEVATOR.
The elevator is not the same as a horizontal stabilizer. The elevators are attached to the trailing edge of the stabilizer.

The stabilizer is used to adjust (trim) the pitch of the aircraft, nose up/ nose down, usually with a trim wheel, one setting for take-off and or climb and yet another for cruise, using gradual adjustments. This is accomplished with a jack-screw connected to the forward edge of the horizontal stabilizer.

The elevators are also used for controlling the pitch of the aircraft but through pilot inputs at the yoke/side stick (or auto pilot), making continuous adjustments required during the course of flying. The actuators are buried in the aft edge of the stabilizer and are usually hydraulic.

The CAUSE of these two events are completely unrelated.

 

To the best of my knowledge, a lone jack screw controls the horizontal stabilizer on all commercial Boeing aircraft and more than likely Airbus as well.

 

Yep, and with thin margins, I always fear that maintenance is the first area to be cut!

 

Wrong. IMPROPER maintenance. Huge difference.

It costs the same to do it properly as improperly. The results though are completely different.