Comment by yutyut | Hacker News Reader

Comment by yutyut | Hacker News Reader

To armchair-quarterback a decades-old incident: I think it was definitely the wrong choice to continue to LAX knowing that field (and the entire coastal region) was IFR. They were essentially controlling the aircraft pitch (and airspeed/altitude) solely with thrust and configuration changes.

It's a miracle (and it speaks to the superb piloting abilities of the Captain/crew) that they were able to maintain a prescribed glideslope while in IMC.

Having flown in the area for several years, I know that the marine layer never (almost) extends east of the 'Peninsular Ranges' of San Diego / South OC. There are a number of clear-air diverts to the East (March/Ontario Maybe, NAF El Centro, probably best) that certainly would have been a better decision(1), given the nature of their emergency.

Had the crew 'balled it up' on final approach due to vertigo or loss of SA in the clouds, I think it's likely that the mishap board would have found pilot error--due to poor selection of a landing site--as the final 'causal factor'(2) in the so-called Swiss cheese model that leads to a mishap.

Note 1: The pilot's concern with runway lighting is valid but I think a ten-minute breather above the clouds to coordinate with those fields would have answered the question on whether a tower was staffed. Pilot controlled lighting is also an option.

Note 2: And they would have balled up a large aircraft in one of the most densely populated areas in the U.S.

The question of landing choice highlights a number of concerns, all well-addressed especially in McMahan's account.

The region is California. Considered landing locations were San Diego (a notoriously short and crowded field with a difficult, over-city approach), Palmdale and Edwards AFB, both closed, Las Vegas and Phoenix, both requiring high-altitude flight over mountains with potential turbulence, and LAX, with a long runway and over-water approach.

I was surprised other inland fields, say, Bakersfield, weren't mentioned, though I'm also not a pilot and don't know the runway lengths or airfield situation generally.

The thing about a disaster is that you're operating under greatly increased constraints, and limited options. The question to be addressed is "what is the next best option?".

Given the circumstances of this incident, instrument approach to LAX still seems like a reasonable option. The principle fault lay in controls, not instruments, time-in-air was a risk, avoiding overland travel, and preserving the option of a sea ditching, were both prudent considerations.

It's possible that McMahan could have inquired as to viability of a Palmdale or Edwards landing with ATC, and it appears he didn't. Given his and crew's workload, that's understandable.

All good points. I suppose my bias is skewed by having a good amount of instrument time and realizing how much higher a workload can get during an instrument approach. I’ll run it by some colleagues at work and see what their take is on it.

Something tells me the mainline Captain from the post also has "a good amount of instrument time."

Certainly, but the average HN user most definitely doesn’t.

To add to this, the pilot also mentions fuel as another primary reason that Phoenix or Las Vegas were not considered.

Bakersfield Airport is the same distance from LAX as San Diego. Would they have had enough fuel to basically double the flight length?

Obviously I'm missing something, but I thought all the concerns you express here were adequately covered in the PDF. I'm not a pilot, but the reasoning given there seemed pretty watertight to me.

I don't have time now to cross-correlate what you're saying with the article, but I hope to get time later to learn more about the discrepancy.

To summarize my point: It was a high-risk decision electing to do an instrument approach at LAX. I don't think the risks given by the Captain in attempting to divert were adequately weighed against the risks of going into the clouds (with such an emergency). I think electing to divert to a field with clear sky was the less risky choice.

Anyway, all's well that ends well.

The captain lays out his selection of the airfield, runway and approach procedure fairly succinctly in the PDF, and the limited but stable control he had over the aircraft.

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