OPINION

Secret of powerless flight

What pilots can do when the engine behaves like a prat, and Whitney misses the high notes. Why are aircraft engines failing?

by Vijay Verghese/ Editor

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An Air France A380 saw an angine blow up over Greenland en route from Paris to Los Angeles on 30 September 2017. The flight landed safely in Canada.

PRATT & Whitney is a not a name that springs to the mind of most travellers. Yet it is a substantial aerospace component manufacturer with the sort of antecedents that would make Rolls-Royce or BMW blush. Mounted discretely beneath the wings of numerous aircraft, its sturdy engines have since 1925 powered everyone and everything from the US Navy and Amelia Earhart to the current Euro darlings – the Airbus A320neo and the A321neo.

It is literally a company with high flying credentials.

Troubling then that in late 2015 one of its first customers for the Neo engine, Lufthansa, was left twiddling its thumbs after it turned out the engines had a problem with their starting warm-up. It took too long.

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In early 2016, testing for the new A320neo suffered another setback when it was found an oil pump failed while an engine had been allowed to ‘windmill’ on idle. Eventually P&W resolved the issue and the Lufthansa Neos took to the skies.

{What sent the alarm needle shooting to the red zone was the fact that this was the 22nd engine failure the airline had experienced in two years...

It has not been a smooth ride since. There have been reported problems with the engines feeding erratic messages to the pilots, adding to the list of checks prior to take-off. Airlines fretted this might require an additional pilot in the cockpit – something passengers would readily welcome, but precisely what new-fangled fly-by-wire technology was designed to eliminate.

In India, the issue of Pratt & Whitney’s worrisome engine performance reached a new milestone late January 2020, when budget carrier IndiGo’s A320neo flight 6E-5384 from Mumbai to Hyderabad suffered an engine stall shortly after take-off. The engine failure was heralded by telltale vibration and a loud ‘bang’. The plane returned safely to Mumbai.

Twin-engine planes like the A320neo are built to fly on one engine (including at take-off) so the loss of an engine is not of itself calamitous. What sent the alarm needle shooting to the red zone was the fact that this was the 22nd engine failure the airline had experienced in its A320neos over two years of operation.

Both IndiGo and GoAir (another Indian budget carrier) have received and affixed modified engines from P&W that have addressed the stall problems. But a lack of supply means all engines have not been modified as yet.

The Directorate General of Civil Aviation India moved speedily and insisted that all airborne A320neos have at least one modified engine while replacements are sought. The DGCA was in favour of a complete refit by 31 January 2020 but later changed this deadline to 31 May to allow time for all 150-odd aircraft to be kitted out anew.

It is a serious quandary – matching the passenger travel imperative (and airline revenues) with safety. There are a little over 550 A320neos worldwide flying with cranky Pratt & Whitney 1100G engines. Is a 50 percent safety threshold sufficient? We would argue not. Good engines seize up too. Not just unmodified ones. Any manufactured item is bound to suffer wear and tear. There can be maintenance glitches. The Indian DGCA safety calculation assumes the good (modified) engine is 100 percent reliable. And here it is lifting from the European Aviation Safety Agency (EASA) 2018 playbook.

The P&W 1100G engine (that Airbus stopped accepting early 2018) has suffered a litany of problems – excessive engine vibration, combustion chamber distress, and failures with the gearbox and low-pressure turbine.

It certainly adds a fresh worry for passengers already obsessed with the B737MAX. But who on earth checks on the engines?

General Electric's GEnx-1B engines for the B787 Dreamliner had considerable issues with tests and aborted flights in 2012. The Rolls-Royce Trent 1000 engines for the B787-9 and B787-10 similarly played up from 2017 to 2019 causing considerable headaches for airlines like Air New Zealand, ANA, British Airways and Virgin Atlantic.

The earlier Trent 900 had a troubling track record too having exploded and ripped the engine cowling (thus disabling the hydraulics) on a Qantas A380 in November 2010. That aircraft turned back and landed safely at Singapore’s Changi Airport, more a testament to the pilots’ skills than hardware engineering (the reverse thrusters failed too along with the automatic braking system). On 30 September 2017 an Air France A380 suffered another 'uncontained' engine loss over Greenland but landed safely in Canada.

Engines do fail. According to the US National Transportation Safety Board and the FAA, in 2014 the country had a little over 150 accidents due to power loss. It was the second biggest contributor after ‘loss of control inflight’. A safety-obsessed country like Australia deals with about 12 engine failures a year.

The good news is that planes are built to glide as well though this requires skill, and cruising height at time of power loss. Contrary to panicked imagination fuelled by disaster movies, there have been several cases of pilots successfully gliding their stricken craft to safety, ditching in rivers or open fields.

On 23 July 1983 an Air Canada B767 famously ran out of fuel (there had been a computing error after the switch to the metric system) and the pilots glided the plane onto an unused military airstrip at Gimli that was hosting drag races at the time. There was no loss of life and the incident is reverentially referred to as the ‘Gimli Glider’. In Indonesia, on 16 January 2002, a Garuda B737 lost power in both engines after encountering a hailstorm. The pilot ditched in the Bengawan Solo River, losing just one crew member.

Better known in more recent years is the ‘Miracle on the Hudson’ when on 15 January 2009 a US Airways A320 successfully ditched on the river after a bird strike took out both engines.

Planes can glide with the right person in charge. Now let’s get those engines fixed.

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