Monday, May 14, 2007

There But For the Grace of God...

I've been waiting to get more of the story before writing this post, since it's a bit of a sensitive subject around here and one that the company would probably rather I not blog about. I think there are some related safety concepts that are worthwhile to discuss, though. Now that I've heard the Captain's side of the story, I'll relate some thoughts on my company's overrun incident on Rwy 16C at Seattle a few months ago.

In the last post, Fred commented that pilots seem to have an "inordinate attraction to analyzing accidents and incidents." He's right. There's probably a bit of a voyeuristic attraction and there's occasionally some armchair quarterbacking involved, but most pilots regard accident analysis as an integral part of their professional education. For me, the greatest value lies not in picking out the crew's major mistakes but in identifying the familiar elements - the situations I can see being in or the actions I could see myself taking. It's the perfect antidote for invulnerability and complacency. In this particular case, it's easy to see that a crew ran a near-STOL airplane off the end of a 9426 foot runway and dismiss it as nothing more than a monumental screwup. Closer inspection shows just how it could happen to you or I.

The incident took place on a foggy Seattle morning with Category III ILS approaches in use. All Cat III approaches at my company are hand-flown by the Captain using the Heads-up Guidance System. The runway visual range (RVR) was hovering near the approach minimum of 600 feet. In fact, the RVR at the far end of the runway, which is not controlling, was lower than 600. The crew planned on rolling out to Papa taxiway [TAXI CHART], which is significantly further down the runway than where we typically exit under normal conditions. Due to the poor visibility at the roll-out end of the runway, the crew missed Papa and subsequently decided to exit at the last taxiway at the runway's end, Quebec. They didn't see this taxiway until the last moment and only then realized they were still doing about 50 knots. There was nothing to do but throw the props into reverse and stand on the brakes. The airplane ran over a couple of threshold lights before coming to a stop, but nobody was injured. The airplane did suffer significant damage, and the incident was a major embarrassment to the crew, the company, and the FAA.

I'm sure many of you are wondering what in the world they were doing at 50 knots in such thick fog. What few realize is just how few visual cues there are use in estimating speed in this kind of visibility. Both of the crewmembers were peering outside for the first sign of taxiway Q, not at their instrument indications. They had no idea they were still going so fast. One major psychological factor was having traffic not too far behind them on the ILS. Missing taxiway Papa likely exacerbated the situation by hurrying the crew to get off on Quebec rather than slow down to find it.

Those who know anything about the Megawhacker will likely question why the crew planned to exit most of the way down a 9426 foot runway when we normally exit in half the distance without trying. This is where it gets interesting.

At the time of the incident, Seattle's SMGCS program was in effect, prompting crews to use the correct Low Visibility Taxi Chart. The chart in use showed taxiways P and Q as the only "low visibility taxi routes" exiting Runway 16C. For years, the FAA had maintained - and the company trained - that these routes are mandatory, so that when low visibility operations are in effect, one must roll all the way to P or Q. In the Megawhacker, this means adding power after touchdown to keep up your speed. In the aftermath of this incident, the FAA is saying that the crew was misinformed and it's actually permissible to exit on any lighted taxiway! Mind you, this is not what the FAA or the company taught in the past. I know Captains that were given demerits in the sim for exiting on the "wrong" taxiway after a Cat III approach. To be sure, the crew was at fault for hurtling past the end of the runway, but in my opinion it was the FAA that put them there in the first place. I have yet to hear an explanation of just what exactly a low visibility taxi route constitutes.

This is what is known as a "system error" - where poorly thought out regulations, procedures, or training leads to or contributes to an accident or incident. The classic systems error accident was the American DC-10 that crashed on takeoff after shedding an engine that was installed using a "money-saving" procedure that turned out to unapproved by McDonnell-Douglas. The cause-and-effect relationship isn't nearly so direct here, but I have no doubt that the system error was a contributing factor. For me, the lesson to be learned here not a new one: Procedures are not the end-all and be-all of piloting. They are set down by humans and are therefore fallible; they can even lead you down the wrong path. I think Earnest K. Gann said it best: "Rule Books are paper. They will not cushion a sudden meeting of stone and metal."

When you look at the factors that came together to cause this incident, you can see that while responsibility ultimately lies with the Captain, this is something that could've easily happened to any of us - there but for the grace of God go I. Cat III approaches at Seattle are a pretty common occurance for me, as is pressure to get off the runway for the next guy. Although this time nobody was hurt, the incident will follow the pilots through their careers. It should provide ample motivation to read the regs and procedures with a critical eye for well-intentioned dictates that reduce the margin of safety, become aware of the built-in "gotchas," cry foul when necessary, and exercise Captain's authority when in the left seat.

8 comments:

Ron said...

Were the pilots terminated by the airline, or do they still work there?

Do you think they'd ever be able to get a job elsewhere?

Ron said...

Oops. I just remembered that the captain was in your recent class. Nevermind. :)

Sam said...

Yeah, they're both still here, they had to do some remedial training. The things I discussed were likely mitigating factors in the way the company and the FAA dealt with them. I don't know the FO, but I do know the CA and have flown with him several times. He's a good captain.

I won't say they *won't* be able to get a job elsewhere, but this definately makes it harder. There would definately be a discussion about it during any interview.

Fred said...

Complex systems, by definition, are difficult to manage. Technology can help, but as you said, Sam, ultimate responsibility lies in the box between the captain's ears.

System (and to a lesser extent, human) failure has always been a tremendous tool to inform us, but I wonder, apart from the cogent solutions you've pointed out, what else, tangibly, can be done to mitigate these kinds of situations? Perhaps a sort of "no pressure, pilots, take your time." ATIS-type announcement? :-)

Joel P. said...

Interesting...

In nice weather do you usually exit on J? Do you try to exit on M or N so you end up right next to the terminal?

Anonymous said...

Sam,

Any thoughts on why this incident is not in the NTSB database?

David

Sam said...

Joel - In good weather we could easily get it stopped by J, but we tend to roll out to M, or sometimes N if we're parking on the south side of our ramp.

Anonymous- Yeah, it did not meet the NTSB 830 definition of accident. I think the damage to the airplane made it come close to an accident, but in the end the FAA & company decided to treat it as an incident.

Traytable said...

I know just what you mean about lack of visual cues in fog... i was driving once in fog and/or bishfire smoke (quite rare here for fog), thinking I was going slowly... looked at my speedo and was doing 70kph...! After that i was checking every few seconds but that is really a "high stress" environment! Meanwhile, idiots were passing me at I'd say over 100kph!!!