Mar 15, 2007

Don't Worry, Be Happy...

Before any nervous passenger gets freaked out by RTO hazards, I'll point out that after thirty years of airline flying, with something like 8,000 takeoffs, I’ve experienced a grand total of zero such events. In one case I aborted a takeoff at 80 knots which is the arbitrary speed defining an RTO as serious-enough to warrant a “mayday” and a full incident report. In a few other cases, we powered up the engines for takeoff, but immediately discovered a problem and discontinued the roll. In those cases the RTO is a non-event. There just isn’t enough kinetic energy embedded in the aircraft to cause problems.

Below is a video showing a passenger’s point of view of a more typical RTO - if there is such a thing. The commentator includes inaccurate technical jargon so ignore most of his remarks and sub-titles. (Although this does illustrate how large the disconnect can be between the view from the passenger ranks and the flight deck.)

Advance the video to 5:00 minutes and pick up the event as they enter the runway.

At about 5:35 the engines rev up to takeoff power.

AT 6:10 the engines suddenly decelerate as the Captain aborts the takeoff. There seems to be a few seconds of shakiness in the camera just before the RTO and I wonder if it reflects actual shaking in the airframe. We are never told the reason for the abort, and I haven’t been able to find any other information about it. The RTO speed looks to be in the range of 100+ knots (120 mph/190kph), but I’m just guessing.

(Ignore the videographer’s remarks about V1 etc. because they’re completely wrong.)

Whatever the reason for the abort, the Captain taxis the airplane off the runway and back to the ramp area. Obviously he's not overly concerned.

At 10:05, we see the fire chief using a hand-held sensor to check the brake temperatures before letting anyone near the airplane.

At 10:20 we see another pilot taking photos of something… which turns out to be the result of fuse-plugs doing what they’re meant to do.

At 10:30 we see the four tires on the right side bogie gone flat from melted fuse plugs.

If the RTO happened at a relatively low speed, why did these brakes and tires get hot enough to melt the plugs? Good question - I’m glad you asked. I’m going to speculate that the camera shakiness really was significant and there may have been a grabbing brake or under-inflated tire on the right main gear. This could explain the sudden vibration as the associated disc began overheating and distorting or a tire suddenly went flat as its fuse plug melted....

There are certainly other possibilities to explain this RTO, so I repeat, I’m only presenting one possibility. Take it with a large dose of salt.

Here's the video:


Ron said...

Boy, you weren't kidding when you said the captions were to be ignored. I didn't realize the outer marker was at the edge of the runway... :)

I saw a fully loaded FedEx Airbus abort a takeoff from KSNA (5700' long runway) at what must have been pretty close to decision speed. The brakes caught fire just as in the 777 certification video. It's amazing how much punishment the brakes and landing gear can endure.

ward said...

The commentary, both the subtitles and the narration is incredibly annoying.

Aviatrix said...

Oh the melodrama. Life changing?

I think the most important thing to be learned here is that passengers take every abnormality very, very seriously. An inconvenience to me is heart-stopping to them. Although I might have accepted the tape, not knowing how annoying the commentary was going to be.

"Seconds From Death!" -- good name for a blog.

Aluwings said...

Oh yeah, Ward - sorry 'bout that ... I considered using Tubesock to try to edit down the video and take off the sound/subtitles ... but what the heck.

Aviatrix, as you point out, we have little idea sometime how the pax are interpreting things that we don't have time to explain. Or the vocabulary - aviation lingo is so full of jargon, shortcuts and acronyms.