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.
Ryanair has been identified in the UK Consumers Association publication “Which?” as the air carrier against which airline awfulness is benchmarked, and it has found that – by one particular measure, British Airways is even worse.
Airlines examined in this survey are among those offering services to or from British airports, and Which? says it is based upon a survey of 6,500 passengers who travelled in the last year. The consumer champion reports “a gulf in standards between the best and the worst”, and it places Jet2 comfortably at the top of short-haul ratings, with Ryanair at the bottom (and Wizz almost as bad).
In long-haul, Singapore Airlines tops the league, with British Airways firmly at the bottom of the nineteen carriers listed, and Air Canada close to it. Indeed, the mighty American Airlines scores much the same as BA, but can claim a Customer Score of 65% against BA’s 62%.
Which? scores all the airlines on 12 categories across the service spectrum. In each category airlines can win from one to five stars, and an overall customer score out of 100. As an example, Jet2 (short-haul) earned five stars for customer service, four in several categories, and in none of the cateories did it win fewer than three stars. Ryanair, on the other hand, didn’t earn more than two stars for anything, and scored one for boarding, seat comfort and food.
Asked by Which? to comment on the survey results, Ryanair had this to say: “Ryanair this year will carry 200m passengers…Not one of our 200m passengers wish to pay “higher prices” as Which? falsely claim.”
Indeed, Ryanair has always been totally unapologetic, as I pointed out in my recent obituary for enjoyable air travel “Surly Bonds (Part 2)”. Quote: “One of the industry’s extant personalities, Ryanair’s chief exec, Michael O’Leary, almost encourages the impression that he chuckles at the pain he can persuade his passengers to undergo to knock a Euro or two off their fare! They just keep coming, he crows. And he’s right, they do – in ever larger numbers!”
But what excuses can British Airways field? It scored lower even than Ryanair on its response to customers who ask for assistance of any kind. Meanwhile on short-haul its highest score was three stars, with a mere two for boarding, seat comfort, food and value for money. On its long-haul routes BA earned four stars for its booking process, but only two on seat comfort, food, cleanliness and value for money.
The UK flag carrier responded: “This research from Which? is entirely at odds with comments from the hundreds of thousands of customers who we know do travel with British Airways and then tell us about their experience.” BA then, in a style reminiscent of recent UK politicians attempting to mitigate dire poll results, lists all the investment it has recently made in cabins and customer service, finally adding: “This [feedback] is also reflected in a recent independent study from Newsweek, which surveyed 17,000 people who voted us their Most Trusted Airline Brand.”
Great brands – and British Airways was indeed a great brand not long ago – can survive a period in the doldrums, but trust can quickly be squandered.
This blog has already vented about the deadly tediousness of air transport today, and the complacent acceptance by the industry of mediocre standards. Flying used to be considered a glamorous and exciting mode of travel, and could be again if spiced with a little imagination.
If that imagination is not invested, the air travel industry will be self-limiting, and environmentalists will be able to celebrate its shortcomings.
The fatal mid-air collision over the Potomac River next to Washington Reagan airport on 30 January is seen by many industry commentators, including myself, as an accident waiting to happen. Today it happened.
A PSA Airlines Bombardier CRJ700 twinjet (N709PS), operating as American Eagle flight 5342 from Wichita to Washington, collided with a US Army Sikorsky H-60 Blackhawk over the Potomac. Authorities now say there are not expected to be any survivors among the 64 people on board the PSA flight or the three crewmen in the Blackhawk.
The collision occurred at night but in good visibility, at a height of about 300ft, just as the PSA CRJ turned onto short final approach for runway 33 at Reagan. The airport is right next to the west bank of the Potomac, and the CRJ had been tracking north following the river. Washington tower asked the CRJ crew if they could accept a landing on runway 33, instead of 01 which they had been expecting. A CRJ pilot confirmed that they had visual contact with runway 33 and could accept it. When they approached the extended centreline for runway 33, the crew turned left to position on final approach, and the collision occurred just as they started to cross the river.
Reagan airport is very much a downtown airfield, with the heart of Washington just across the river to the north east, the Pentagon with its helipad immediately to its north west – and Arlington beyond that, and Alexandria to the south. The river is one of the principal corridors for helicopter traffic, most heavily used by the military and White House movements, and Reagan airport itself operates most of the time close to capacity. It is popular with politicians, business people and lobbyists because it is much closer to the heart of power than the city’s international airport at Dulles, more than an hour away in Virginia.
It is not clear whether any party to this accident made a classifiable mistake. It was nighttime, but visibility was good, and air traffic controllers were relying on pilots being able to make visual contact with other close aircraft when they had been advised of their relative position. But it would be easy for the navigation and anti-collision lights of the two aircraft to be lost among the city lights on both river banks, and easy to identify the wrong set of lights before confirming to ATC that they believed they had the other aircraft in visual contact.
In other words, this is a very busy environment, and because of political pressure to keep a downtown airport constantly available for use, Reagan airport and the terminal area around it operates knowingly with risk margins that seriously need reviewing. They probably will be reviewed as a part of the investigation into this accident, but the warnings have been there for years, and still the politicians want their downtown airport to continue doing business at a rate that entails serious risk.
In March 2024 the President and CEO of the US-based Flight Safety Foundation Hassan Shahidi remarked on the fragility of the US air traffic control services in the face of continually escalating demand. He wrote then: “The ongoing issues with runway incursions and other serious safety and quality concerns signal that safety buffers within the industry are being stretched thin. The industry is grappling with numerous challenges, including the recruitment, sourcing, and training of tens of thousands of new workers, the rising demand for travel, and the need to accommodate new and diverse types of operations within the airspace system.”
Speaking about the Washington accident today, President Trump has already been critical of air traffic control, but sees the problem as being caused by the Federal Aviation Administration’s (FAA) adherence to diversity recruiting policies, which he has now stopped. The FAA, a government agency, is responsible for providing America’s air traffic control, and it depends for its funding on the government and congressional approval. If it is under-funded, as the Flight Safety Foundation’s Shahidi implies in his quotation above, President Trump has the power do something about it beyond stopping a diversity recruiting policy.
American Flight 965, a Boeing 757 descending at night toward its destination at Cali, Colombia, collided with an Andean mountain ridge, killing 159 crew and passengers. Miraculously, four passengers did not die.
The accident report that emerged from the investigation laid all blame at the feet of the pilots, softening the blow by citing some flight management system navigational anomalies as contributory factors.
Recently an independent re-examination of the data by a team of aviation and accident investigation experts has concluded that simply writing off the crash as “pilot error” was a bad decision. The pilots were among American’s best, yet the crew exchanges on the cockpit voice recorder, according to their peers, demonstrated a degree of confusion that was out of character.
Initially the Colombian/American investigation team believed alcohol in the pilots’ blood might have been a factor, but later forensic testing confirmed the alcohol was a product of tissue degeneration. Having ruled out alcohol as a cause of the pilots’ uncharacteristic confusion, the investigators failed to ask whether there might have been an alternative explanation for it, confining the event to history as simple pilot error.
After nearly two years of grounding, Boeing’s 737 Max series has been cleared by the US Federal Aviation Administration to carry fare-paying passengers once again.
This is the first step in a redemption process for one of the world’s truly great engineering companies. Like a boxer who dropped his guard for just a second, Boeing has taken a punch that has knocked it to the canvas, and the referee had started counting.
Now, air traveller reaction is nervously awaited. Will the public believe claims by the FAA and Boeing that, together, they have confined to history the flaws that caused the 737 Max fatal crashes in 2018 and 2019?
The FAA – blamed along with the manufacturer for the lapses in design oversight that led to the two accidents – has declared the aircraft safe to operate in America. One by one, other national aviation authorities (NAA) are expected to follow suit.
Oversight of the type’s rehabilitation continues to be the FAA’s responsibility, but decisions on the systems and software changes applied to the Max have been made by multinational teams. Bodies formed to decide what changes were needed – and then to see them implemented – included the Joint Authorities Technical Review (JATR) representing nine nations plus the European Union Aviation Safety Agency (EASA) – and the Joint Operations Evaluation Board.
The relationship between the FAA and Boeing was much criticised in the accident investigations and the JATR review process . For that reason, the reaction of EASA to the Max’s clearance to fly is seen as critical.
Not only is EASA the agency that oversees safety in the region containing the largest group of aerospace industries outside America, but its contribution to the JATR recommendations made clear EASA was not happy with the FAA’s former piecemeal approach to certifying critical changes applied to the 737 Max.
Its opprobrium was directed particularly at the FAA’s approval of the flawed Manoeuvring Characteristics Augmentation System (MCAS), unique to the Max, and not used in earlier marques of 737. It recommended “a comprehensive integrated system-level analysis” of the MCAS, and of its integration into the total system-of-systems that constitutes a modern aircraft (for more detail, see “The Failures and the Fixes”section following this article).
So it was with heartfelt relief that Boeing heard EASA’s executive director, Patrick Ky, report on Max progress to the European Parliament Transport Committee on 29 October. Ky told them: “We are fully confident that, given all the work that has been performed, and the assessments which have been done, the aircraft can be returned safely to service.” Ky’s statement suggests EASA will re-certificate the 737 Max in Europe soon after the FAA’s announcement.
Meanwhile, out in the real world, Covid-19’s near-immobilisation of commercial air transport worldwide has rendered the Max’s long grounding almost invisible to the media and the public. Because of the far lower level of air travel activity, the airlines have been able to live without the 387 Maxes already delivered to them, and also without the additional 450 that have rolled off Boeing’s Renton, Washington production line since then. The latter are all in storage, awaiting any updates not already incorporated, and ultimate delivery.
Although clearance to fly has now been delivered, even in the USA the airlines will not instantly be re-launching their already-owned 737 Max fleets. The status of all the proposed software and hardware modifications to the type will not have been confirmed until the moment the FAA signs it all off.
American Airlines has said it hopes to start getting its Max fleet airborne before the end of December.
REUTERS/Nick Oxford/File Photo
Once the FAA has done that, getting the Max fleet ready for the sky will be an aircraft-by-aircraft, crew-by-crew process. In many airframes, a knowledge of what changes were coming has enabled a great deal of the work to be done. But also, because of the hardware and software changes to the Max, the crews have to be trained to use the new systems.
Incidentally, while the Max series was grounded, the FAA decided to order some additional modifications – completely unrelated to the crashes – to bring the type fully in line with modern safety regulations. For example, one of these involves the re-routeing and separation of wiring looms that the 737 had previously been allowed to sidestep under “grandfather” rules.
The number of lessons for manufacturers and regulators to learn from this aerospace drama is legion.
The failures and the fixes
The failures
Just a reminder: the 737 Max series fleet was grounded in March last year as a result of findings from the investigations into to the Lion Air and Ethiopian Airlines fatal crashes, respectively in October 2018 and March 2019.
The primary causal factor of the Lion Air Max crash was erroneous triggering of its manoeuvring characteristics augmentation system (MCAS) by a faulty angle of attack (AoA) sensor, according to the Indonesian final accident report. It is at the MCAS that Boeing’s corrective efforts have mostly been directed.
In both the accidents, the aircraft’s AoA sensor that feeds data to the MCAS wrongly indicated a very high AoA soon after take-off. The system reacted by providing nose-down stabilizer rotation that took the pilots by surprise. They did not understand the reason it kicked in, and their efforts to reverse the strong nose-down pitch did not succeed. Both these events occurred soon after take-off, and because the MCAS kept repeating the nose-down stabilizer in response to the continued erroneous high AoA sensor signal, the loss of height quickly resulted in impact with the surface.
During the examination of all the issues arising from the accidents, the JOEB was aware there were solutions to the situation in which the crews found themselves. But the fact that two crews in different regions of the world were so confused by what the MCAS was doing that they lost control had totally eclipsed pilot failings as the main issue.
MCAS was designed to trigger only in a specific flight configuration that causes the Max’s centre of lift to move slightly further forward, delivering a slight nose-up moment that can be countered by flight controls. This configuration is a combination of relatively low airspeed, flaps up, with the aircraft being flown manually. In the case of the Lion Air and Ethiopian flights, the pilots decided to continue to fly the aircraft manually during the early climb, rather than engaging the autopilot, so this precise flight configuration was encountered as soon as the flaps were fully retracted.
With flaps up, and still at a fairly low airspeed, the aircraft would be at a high angle of attack, and not far above the stall. FAA regulations require that, in the proximity to the stall, one of the “feel” cues to the pilots is that there should be a linear increase in the required control column force versus elevator displacement response, but the Max’s aerodynamics in this configuration had negated this effect, and MCAS was designed to restore that pilot cue automatically.
The JATR decided that MCAS’ fatal design weakness, above all, was that it was triggered by a single AoA sensor with no backup in case the unit had a fault or suffered damage. It seems Boeing and the FAA had overlooked that possibility, and had not explored the potential effects of erroneous inputs. Their excuse at the time was that the system was not seen as a critical one, rather as a refinement.
The fixes
The 737 Max had always been fitted with two AoA vanes, but originally only one was wired up to MCAS, and there was no flight deck indication of a disparity between the two sensors if a difference developed, which could have warned the pilots of a potential vane fault.
The hardware fix agreed by the JATR was that both AoA sensors would now feed into the MCAS, there would be an automatic comparison between them, and if there was more than a small disparity the MCAS would be locked out completely, because the aircraft can be flown without it.
The software fix also ensures that – now – the MCAS only operates once per high AoA event, so the repeated nose-down pitch demand by the stabilizers that led to the two accidents would not occur. In addition, the two flight control computers (FCC) now continuously cross-monitor each other.
After the hardware and software changes, the final improvements – overseen by the multinational JOEB – are to pilot training and cockpit drills for the Max series.
Now, even if the pilots are coming to the Max from the very similar 737NG series, pilots must undergo a one-off training session in a Max full flight simulator. This involves recovery from a full stall, dealing with a runaway stabilizer, practice manual trimming at high speeds (and therefore high trim loads), and crew cooperation on all these exercises.
Non-normal checklists have now been compeletely revised, and contain updated procedures that concentrate particularly on the operation of the horizontal stabilisers and trim controls, both in normal operation and in the case of all potential faults. The drills deal with runaway stabilizer, speed-trim failure, stabilizer out of trim, stabilizer trim inoperative, airspeed unreliable, altitude disagree, and AoA disagree.
Computer based training (CBT), containing video of crew exercises using the real controls, teaches drills for the following: airspeed unreliable, runaway stabilizer, the speed trim system, trim controls, and differences between the autopilot flight director system (AFDS) in the NG series and the Max series.
Testing the changes
Boeing and the FAA say they have put in 391,000 engineering and test hours developing the solutions, which have then been tried for 1,847 hours in simulators and for 3,000 airborne hours in the real aircraft.
Learmount.com 