Last Saturday, February 20th, there were two separate incidents involving Boeing aircraft and engine failure. The resulting backlash has primarily centred around Boeing, but the attention here needs to be directed elsewhere.

What happened?

Last week, United Airlines UA328, a Boeing 777 equipped with PW4077’s, reported engine failure. The report came shortly after take-off while the jet was en-route to Honolulu from Denver. Following the sound of an explosion, passengers on-board witnessed an alarming sight: the right engine was stripped of its nacelle, violently shaking and spewing flames from its combustion chamber. Vibrations tremored through the jet as the damaged blades continued to spin. Passengers captured video of the damaged engine on mobile phone footage while fire alarms rang out in the cabin.

During this, the pilots acted quickly and professionally. They issued a mayday call and immediately turned back to Denver. Following all the correct protocols, the aircraft landed safely. It is, of course, something that pilots receive training to handle and is also a scenario frequently practised in the sim. But despite this, debris from the damaged engine fell over the city suburbs. This included the engine inlet, which landed directly outside a local resident’s house. Miraculously, no-one was injured.

Unfortunately, the same can’t be said of the incident involving the Longtail Aviation Flight 5504. On the same day, a Boeing 747-400 cargo jet equipped with a PW4056 engine also suffered dramatic engine failure in a bizarre coincide. This time it occurred en-route to New York from Maastricht Aachen Airport. As was the same in the Denver incident, the pilots safely diverted to Liège airport and landed the aircraft without more problems. In this instance, however, an elderly woman in Meerssen suffered injuries due to the falling engine debris.

More trouble for Boeing

Following these incidents, the spotlight is on Boeing once more. The US aircraft manufacturer has grounded significant numbers of its 777’s and has released a statement recommending the suspension of operations involving 69 in-service and 59 in-storage 777’s. The aircraft manufacturer is currently overseeing it’s 737 Max regain certification in different markets after two years out of service. Meanwhile, it has also encountered large issues due to the COVID-19 pandemic and its repercussions on the travel industry. This is the last thing they need right now.

While the heightened focus on Boeing is predictable, the focus now in the aftermath should be on Pratt and Whitney – the manufacturer of both aircraft’s engines. The issue’s which caused the engine failure most likely relate to metal fatigue. Early investigations have so far indicated that a fan blade fractured at the root, likely causing damage elsewhere in the engine. Whilst blades receive routine inspections – these do not occur before every flight due to time constraints. Pratt and Whitney are now working with the proper authorities to adapt the engine blade inspection schedule for PW4000 engines on Boeing aircraft.

Last weekend’s incidents also parallel the problems found on United Flight 1175 from San Francisco to Honolulu in February 2018. The Boeing 777, also equipped with a PW4000 series engine, suffered engine failure due to a broken fan blade. The resulting inquests deemed that fan blade inspections were not sufficient and that there was not adequate training for inspectors. This time around, United Airlines and its inspection staff will undoubtedly receive a portion of the blame once more.

What’s next?

Keep in mind, only aircraft equipped with Pratt and Whitney turbines have faced grounding. The belief of global aviation authorities is that this should only affect select Boeing aircraft. In the UK, the Civil Aviation Authority are preventing 777’s with Pratt and Whitney PW4000-112 turbines from flying over British airspace. Similarly, the US Federal Aviation Administration is conducting inspections of 777’s with Pratt and Whitney PW4000-112 turbines.

That Boeing are not to blame may seem obvious to many in the aviation. Engine testing is, of course, not handled by the aircraft’s manufacturers. However, in the immediate aftermath of these issues, it is the difficult to discern which party is responsible. Blame is often placed on the largest party involved. In this case that is Boeing, who will not appreciate the heightened scrutiny they are facing.

It can’t be ignored that debris from the engine on the UA328 did damage the aircraft’s wing. So, on one hand Boeing are lucky. But overall, United Airlines UA328 remained relatively unscathed. This was not only because of the pilot’s training and quick reactions but also due to the overall aircraft manufacturing quality. If anything, let’s see this as a testament to both.

Words by Jonathan Ritchie