DC-10 crash nightmare runs again

06/11/202523/11/2025 David Learmount Uncategorized 25 May 1979, American Airlines, Chicago O'Hare, DC-10, engine pylon, Engine separation, Flight 191, Flight International, freighter, General Electric, Kentucky, leading edge slats, Louisville, McDonnell Douglas, MD-11, NTSB, Pratt & Whitney, trijet, United Parcels Service, UPS, wing mounting

On 25 May 1979 the worst airline crash in America’s history occurred during take-off at Chicago O’Hare airport, killing all 271 people on board. Now, on 4 November at Louisville, Kentucky, an unnervingly similar disaster has occurred, also immediately after take-off.

But because the Louisville crash involved a freighter, far fewer people died, and for that reason the event has not received the same international wall-to-wall coverage in the media as the 1979 catastrophe.

Some 46 years may have passed since the crash of American Airlines Flight 191 at Chicago O’Hare, but it remains the worst aviation accident ever to take place on US soil. It also happens to be the first major accident upon which I had to report as a rookie aviation journalist with Flight International magazine, so my memories of it remain vivid.

The similarities between the two accidents were these: both aircraft were McDonnell Douglas (MDC) DC-10 trijet variants; both, late in the take-off run when the aircraft were already committed to take off, suffered complete detachment from the left wing of the No 1 engine.

Flight 191 involved an MDC DC-10-10 passenger aircraft, whereas the Louisville accident involved the most recent variant of the DC-10 series, known as the MD-11, and it was a freighter version operated by UPS with only three crew on board.

The UPS MD-11F engines were Pratt & Whitney PW4460s and Flight 191’s power units were General Electric CF6-6Ds, but the common factor in both cases was that they ripped themselves off their wing mountings, damaging the wings disastrously in the process and making the aircraft completely unflyable. Nobody on board either aeroplane had a chance of survival. At O’Hare two people on the ground were killed, and at Louisville the death toll of third parties is estimated at nine, with at least 11 injured.

The National Transportation Safety Board (NTSB) investigation of the 1979 accident found that improper maintenance practices by American Airlines when they re-mounted the left engine on the wing following overhaul had resulted in damage to the wing mountings where the engine pylon attached to the wing itself. The report says that, when the engine detached, it pivoted upward and passed over the top of the wing as it departed, the separation causing physical damage to the wing leading edge and to hydraulic systems, resulting in the retraction of the left wing leading edge slats which dramatically reduced the lift that wing was able to produce at low speed. The wing dropped uncontrollably, and the aircraft hit the ground inverted.

At this stage all we know about the UPS accident is that the NTSB have recovered the flight data and cockpit voice recorders, and that witness from the ground and wreckage disposion at the site makes it certain that the left engine separated, causing damage to the wing, which then dropped and hit the roof of an industrial unit beyond the runway end. So far there is no evidence to suggest that the separation took place in exactly the same manner that it occurred on Flight 191, nor for the same reason. Additional video information showing the No 2 (tail) engine emitting flame suggests debris from the No 1 engine separation damaged it, making it impossible to maintain level flight.

Additions to detail since the NTSB released a preliminary factual report: the Lousville departure was Flight 2976 for Honolulu, and it took off from runway 17R reaching a maximum height of 100ft (the original statement said 475ft, but the NTSB has now reviewed the ADS-B data from which that was derived) and airspeed of 183Kt. Also, most of the No 1 engine’s pylon was still attached to the engine when the NTSB found it, but probably received additional damage when hitting the ground after detaching from the wing. The separation process began with a fatigue failure of the left engine pylon’s aft attachment lugs, so the engine and pylon detached as a unit from the wing underside. The engine twisted upward and passed over the top of the aircraft, gyroscopic precession causing it to fall to the right of the aircraft’s path, and debris entered the tail engine causing a reduction in power, making descent inevitable.

2024 airline accidents are up

30/10/2024 David Learmount Uncategorized 2024, Airline safety review, airlines, aviation, aviation-safety, Fatal airline accidents, Flight International, Flightglobal, Indonesia, Nepal, news, travel

There are still two months to go before the end of 2024, but the number of fatal airline accidents worldwide this year already comfortably exceeds the 2023 total. We’re not in disaster territory yet because the previous year’s total was exceptionally good.

Prominent risks facing the airlines today, according to incidents this year, include repeated runway incursions and airport air traffic control errors causing collision risk, and a rising number of in-flight turbulence incidents in which passengers and crew are severely injured or – in one case – killed.

Two countries that have had bad safety performance levels for many years – Indonesia and Nepal – have each suffered fatal accidents already this year, suggesting they have yet to get to grips with their national aviation safety cultures.

Each year for the last 44 years I have produced the world airline safety review for FlightGlobal and Flight International, and I have been commissioned once again to carry out their reviews for the current year. As usual, in January, it will provide fine detail of significant accidents and incidents, and analyze changes, trends and safety culture issues around the globe. The last annual review is here.

We wait to see whether November and December will add to the year’s accident total. Or not.

How much airline safety is luck?

15/01/201817/01/2018 David Learmount Uncategorized airline accidents in 2017, airline crashes, airline safety, automation, Flight International, Flightglobal, IFALPA, Institut Superieur de L'Aeronautique et de L'Espace, ISAE, luck as it relates to airline safety, pilot congnitive skills, pilot manual skills, pilot stress, runway excursion, runway overrun, the limitations of flight simulation

If you look at the statistics for fatal airline accidents in 2017, the year looked faultless.

There were no fatal accidents – at least not among the mainline carriers operating passenger jets.

But if you look at the number of near-disasters, and especially if you hear the accounts of what happened on board and imagine the trauma the survivors underwent, you might wonder what made the difference between the mishaps they survived and fatal crashes in recent years that had almost identical precursors.

The answer is luck. Not a scientific answer, but it is the only word in the English language that describes that difference. A study Flight International/FlightGlobal will shortly publish (Flight International issue 23-29 January) contains an analysis of how luck works in today’s air travel.

Giving detail of numerous recent near-disastrous mishaps, the report observes: “Sometimes these mishaps start with a technical problem, but more often they are the result of inadequate crew knowledge, poor procedural discipline or simple human carelessness.”

Many of them ended up as that most common of all airline accidents, runway excursions or overruns on landing, and the result is usually serious and very expensive damage.

Pegasus Airlines at Trabzon, Turkey, 13 January (Twitter World News)

The spectrum of industry discussion about how to deal with this “luck” factor includes – at one end of the scale – automating pilots and their fallibilities out of the picture, and at the other end imbuing today’s crews with a quality referred to as “resilience”. The latter is the ability to face a surprising or unforeseen combination of circumstances with cool logic based on knowledge, situational awareness and skill. That’s what most passengers assume all pilots have.

Airline pilots today are firmly discouraged by their employers from disconnecting the autopilot and autothrottle during revenue flights. There are good reasons for this, the most obvious being that the automation – properly programmed – flies the aircraft more accurately than most pilots can. The argument against it is that if the automation is wrongly programmed, or used unintentionally in the wrong mode, or suffers a rare failure, the pilot reaction to the unintended consequences frequently demonstrates a lack of “resilience”, setting off a chain of events that can lead to an accident.

The question is, if pilots were permitted to fly their aircraft manually more often during revenue passenger flights, would their manual flying and associated cognitive skills be better primed for the unexpected, making a resilient response more likely when things don’t go according to plan? Pilot organisations like IFALPA believe they would.

To many airlines, that idea is heresy. Letting pilots “practice” flying with passengers on board is just not acceptable, they argue. “Practicing” (what pilots call flying) should only take place in a simulator or an empty aeroplane, they maintain.

The main problem with simulators is that, although getting better all the time, they will – psychologically – be no preparation for the real environment. The sense of risk, or fear, and the stress generated by it, can never be replicated in a simulator.

The reason aeroplanes have not been even more automated than they have been so far is that most flights don’t happen exactly as planned, so the pilots have frequently to intervene to make decisions and adjust the trajectory, even if they use the automation to do it.

This is a discussion that will – and should – continue, and the existing polarisation of views also seems likely to persist.

What is really needed is a cost-benefit and risk examination of whether the regular employment of manual and traditional pilot cognitive skills in flight has net advantages or disadvantages for airlines, but such research has never been carried out.

The ideal institution to do it would be the Institut Supérieur de l’Aéronautique et de l’Espace in Toulouse , which has expertise in measuring neuro-ergonomics in working pilots. ISAE has successfully carried out studies of the effect of stress on pilot cognitive and manual skills, and tested ways of re-orienting pilots when they lose situational awareness.

Learmount is dead, long live Learmount.com

01/05/201501/05/2015 David Learmount Uncategorized aviate navigate communicate, Flight International, Flightglobal, Learmount

Followers of the Flightglobal blog “Learmount” – which will soon slide gently into the great digital graveyard – welcome to my new site.

This one will offer much the same as my Flighglobal blog did. It’ll certainly serve the same audience – namely aviation’s front-liners – discussing news that affects their lives and profession.

Why the change?

I am maintaining my links with Flightglobal and Flight International as their Consulting Editor, but after many happy years there I’ve now got my P45 and my independence.

I hope you’ll find this space useful, and enjoy it as well.

Let’s aviate, navigate and communicate.