Hacker News new | past | comments | ask | show | jobs | submit login
Flight 1080 (1978) [pdf] (tristar500.net)
53 points by ColinWright 24 days ago | hide | past | web | favorite | 21 comments

For those wondering what this is about before jumping into the PDF. It is an article from the captain's perspective of a flight in 1977, where a Lockheed L-1011's left elevator jammed (corrosion) during take-off forcing the plane to pitch up.

The captain, Capt. Jack McMahan, was awarded the FAA's Distinguished Service Award for successfully landing the plane by using a thrust differential between the wing engines and tail engine to counteract the upward pitch, preventing a stall.

The (short) Wikipedia article can be found here: https://en.wikipedia.org/wiki/Delta_Air_Lines_Flight_1080

I think this is the incident that Captain VanderBurgh describes somewhere in https://news.ycombinator.com/item?id=21535214

I was wrong. Take a look at "Control Malfunctions & Flight Instrument Anomalies": https://www.youtube.com/watch?v=WfNBmZy1Yuc&feature=youtu.be...


"You see, right here, few of us, certainly not I, are clever enough, 'cause there isn't time to be clever. A critical flight attitude recovery requires training and rote response, 'cause there isn't time to think. You must respond to the training. And it's that response to their training, that initial move that saves the initial crisis, that buys the time to do all the clever things that we all think of, given time."

It's at 33m30s here: https://invidio.us/watch?v=WfNBmZy1Yuc

Preceded by an unsuccessfully handled case.

Possibly within the series. Not that specific video though.

Spoilers for those who've not yet read/viewed.

I'd run across this incident yesterday. Studying various technical disasters is something of a hobby/professional interest, and in particular, the responses of the humans involved.

I first watched the video @ColinWright lists in a comment (https://invidio.us/watch?v=x0cnGeYEGmk), then read McMahan's own account (the PDF here). The Washington Post) also has an excelent article (https://www.washingtonpost.com/archive/opinions/1978/10/08/t...). Wikipedia has a brief article (https://en.wikipedia.org/wiki/Delta_Air_Lines_Flight_1080).

My first thouht on seeing the pilot's bio at the start of the video was "man, what a way to end that career". Reading about nose-up on takeoff and the failures of trim-control attempts brought to mind the 737 MAX story of the past year.

One concept I've been working on is the notion of a hierarchy of failure (or conversely, a success-chain) in problem solving: https://old.reddit.com/r/dredmorbius/comments/2fsr0g/hierarc...

Two elements of that I've been revisiting is the diagnosis / root-cause steps. I'm thinking now that a minimal working diagnosis/root are helpful in crisis, but that rabbitholing into a precise diagnosis when the immediate situation is critical can be a dangerous distraction. If you're flying an aircraft with souls aboard (or even just yourself and cargo), a sufficient grasp to regain minimal control and effect a safe landing is usually enough. And the situation can evolve quite rapidly.... It's a tricky balance to strike.

As the video account continued, I was struck by each of McMahan's responses, and how each was clearly prudent, effective, and/or demonstrated exceptionally high situational awareness. The counterintuitive down-throttling during a pitch-up / stall situation. Throttle control over pitch and roll (a case where a three-engine design proves particularly useful), and moving the passengers forward (a thought I'd had before it was mentioned in the video). The choice of landing sites (and the surprising lack of alternatives in California -- things are really spread out -- though Bakersfield might have been one to consider). Electing for a water rather than land approach to LAX.

The only possible fault I could find was in not testing gear-down performance before final. In another, later incident, NWA 85, October 9, 2002, also with partial loss of control, the crew elected to drop gear early in order to assess aircraft performance. That flight also landed successfully. (https://invidio.us/watch?v=RcAiu2FXeEk)

UA232 also comes to mind as an impossible situation saved by excellent piloting, situational awareness, and crew resource management.

There are any number of sharp contrasts with exceedingly poor pilot/crew response. Two that stand out are Saudi Air Flight 163, with a fire on board. Despite a successful landing, all perished. (https://invidio.us/watch?v=mYX5pBihw3c). Or Air Florida Flight 90, which crashed into the Patomac, following a series of poor pilot judgements regarding anti-icing practices (https://invidio.us/watch?v=gUOMZnFaMos). Air France Flight 447 or the Tenerife incident (latter mentioned in McMahan's account) are other exemplars of poor response, situational awareness, or flagrant violations of procedure.

Good piloting is not always enough -- sometimes an aircraft is simply too crippled to fly, see Alaska Air 261. But in that grey zone between a well-behaving ship and one that won't stay in the sky no matter what, pilot skills matter. And McMahan was absolutely the hero of this story, with excellent assists from his cockpit crew. Speaking of which, it's notable that this short flight had a regular cockpit roster of three -- captain, copilot, and engineer.

The flight attendant response at the end caps the story. The WashPo article proves that not everyone is appreciative.

And, finally: the after-incident root cause analysis shows just how critical the smallest elements in a tightly-constrained system can be. Water intrusion into a bearing disabling control surfaces and leading to near complete loss of aircraft. The specifics of the fault making it extraordinarily hard to anticipate in advance, though I suspect that's now part of some design spec somewhere.

In all an excellent case study.

>Studying various technical disasters is something of a hobby/professional interest

What would be some recommended reading in this area? Not limited to airplanes

And after replacing the jammed elevator, they continued the flight!

I wonder if they'd do that now.


If you continue to break the site guidelines, we're going to end up having to ban you. I don't want to do that, so would you please review them and stick to the rules when posting here? They include: "Eschew flamebait. Don't introduce flamewar topics unless you have something genuinely new to say. Avoid unrelated controversies and generic tangents."


While what you say may be true, the snide side-attack feels very much out of place. There is no reason to have introduced it, as your comment about the pilot being considerate, measured, and thoughtful stands on its own.

And yes, it's a lovely read.

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.

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact