Cause of Michigan's plane crash determined

Submitted by TheDirtyD on

From the Avherald via the NTSB

Link

On Mar 22nd 2017 the NTSB reported that the flight controls moved normally and were free to move, the elevator control tabs moved as commanded, however, the right hand elevator was jammed in a trailing edge down/aircraft nose down position and did not move, while the left hand elevator commenced a large nose up movement as the aircraft accelerated through 152 KIAS and continued in this position for 5 seconds, aircraft accelerating through 166 KIAS with no change in aircraft attitude however. The crew rejected takeoff, the aircraft reached a maximum speed of 173 KIAS. The aircraft went beyond the end of the runway and came to a stop about 1000 feet past the end of the runway. One passenger received a minor injury in the evacuation. The NTSB reported a post flight inspection found the right elevator geared tab inboard pushrod linkage damaged which restricted movement of the right elevator surface but allowed movement of the control tab. After the damaged components were removed, the elevator could be moved by hand. 

The NTSB reported the pilot in command was Ameristar's chief pilot occupying the right hand seat providing captain differences training to the captain occupying the left hand seat and being pilot flying. The chief pilot had accumulated 9,960 hours total with 2,462 hours on type, the captain had accumulated 15,518 hours total and 8,495 hours on DC-9 type aircraft.

 

So I was way wrong in assuming it was pilot error. They rejected due to a mechanical failure of the elevator. So a big hats off to the crew, this could have been a lot worse. Wow I am glad I was wrong that it wasnt pilot error.

 

HL2VCTRS

March 22nd, 2017 at 2:15 PM ^

You seem pretty knowledgeable... so did the high winds really have any impact on this? It sounds like something that would have happened regardless?

TheDirtyD

March 22nd, 2017 at 2:18 PM ^

If the tail was subjected to a very very strong gust directly on the tail it could have caused the elevators linkage to become damaged. I've never flown an MD-80 series aircraft so my knowledge is limited of if thats something that could cause this issue. Sometimes things just break. The real reason to figure out now is why did that part fail?

drz1111

March 22nd, 2017 at 2:34 PM ^

I'd heard that there is one reported case of an MD-80 series elevator becoming jammed in connection with high winds, but those were much higher winds.  

i can't believe these guys realized they had a jammed elevator at high speed and somehow managed to reject takeoff with no serious injuries.  That is some Sully level shit.  The BAMFs on this plane were the ones sitting in front. 

TheDirtyD

March 22nd, 2017 at 2:47 PM ^

There was a case of our company that had to rejected due to an elevator cable broke due to high winds on the tail surface the night before as the plane sat on the ground. The crew went to rotate/ pull back and nothing happened. There was no way the crew would have known this since there isnt an indication in the cockpit on that airplane type that the elevator moved on the pre flight checks. They were at JFK on a runway twice the length so they just taxied in and everyone was okay. An airplanes control surfaces act like large sails in the wind.

 

Link for that one

dragonchild

March 23rd, 2017 at 7:20 AM ^

The answer was fine, and thank you.  I was just poking fun at how, while there's nothing wrong with the release following procedure by not naming names, neither did it do anything to conceal Walton's identity, since that news is already out as well.

kvnryn

March 22nd, 2017 at 2:26 PM ^

IANAP, but it sounds like basically the linkage between the mechanism that controls the right rear elevator and the elevator itself was damaged, so when the pilot tried to put it in position for takeoff, it didn't move.

The elevators are the pieces on the tail of the plane that control the pitch of the plane. These things:

TheDirtyD

March 22nd, 2017 at 2:34 PM ^

Correct they are two seperate surfaces that usually move together.

There are two parts to each side, the forward part called the stabalizer ( its much larger in surface area) the aft part called the elevator.  

In this circumstance one side moved and the other side was actually forcing the nose down (the broken side). So when the pilot pulled back on the yoke ( pilot's control column ) nothing happened they reacted fairly quick (5 seconds) and then excuted a rejected takeoff. 

JeepinBen

March 22nd, 2017 at 2:37 PM ^

I'll never forget the start of ENG 100 when the professor asked us how many of us thought that 99% was a good grade. We all raised our hands. He then asked how many of us would fly on a plane if they were 99% successful.

Pilots did a great job here in the small case when things didn't work right, but it amazes me how well things work 99.9999999% (or so) of the time and are well engineereed.

JeepinBen

March 22nd, 2017 at 2:53 PM ^

We make a very small amount of aircraft product out of the  automotive plant I work at. Mostly redundant safety systems (actuator fails, we have the parts that engage to freeze them so that they're not flapping around) but that's a whole different world considering our auto parts are non-safety critical.

It's easy to sleep when your parts critically failing are somewhat a loss of power in a car - not even brakes! But when you're working on an aircraft component? Better get that one right and robust.

(All of what I/we do are right/robust for all you MGoLawyers)