MIAMI – The FAA has sent out an Airworthiness Directive (AD) ordering the immediate inspection of Boeing 777-200s fitted with Pratt & Whitney PW4000 engines following the recent United Airlines (UA) incident involving the aircraft and engine type. 

The directive notes that the inspection has been ordered due to the recent event in which a United Airlines Boeing 777 aircraft was forced to perform an emergency landing following one of its engines exploding mid-air. According to the FAA, the in-flight failure of low-pressure compressor blades on PW4077 engines resulted in the engine’s uncontained event.

According to the AD, each engine will require an extensive test to determine if any cracks are evident on its blades. The airline has already grounded all of its Boeing 777-200s fitted with PW4000 engines in preparation for the AD. 

The FAA’s directive requires a thermal acoustic image (TIA) inspection for cracks in first-stage LPC blades. Blades that are found to have cracks will need to be removed and replaced. 

The agency stated that other engines of the same type are “likely” to have similar cracking issues and could lead to another in-flight engine fire. 

United Airlines is the only airline based in the US that operates the Boeing 777-200 with PW4000 engines. However, it is likely that other aviation safety agencies globally might mandate inspections of the engine type and ground subsequent Triple-Sevens.

ANA Boeing 777 fitted with PW400 Engines | Photo: Kochan Kleps/Airways

What Led to the Directive?


Two incidents involving the aircraft and engine type are the main causes for the grounding and airworthiness directive.

The first was an in-flight engine fire on a Japan Airlines flight en route from Naha, Okinawa to Tokyo. The aircraft made a safe landing using one engine back at Naha Airport (OKA). 

The second incident involved a United Airlines flight that suffered a very similar problem after taking off from Denver International Airport (DEN). The aircraft also landed safely at DEN, but only after debris—including the cowling—fell from the engine and onto Denver suburbs. 

Immediately following the second incident, Japanese authorities grounded and mandated inspections of the aircraft and engine type. 

Currently, only Japan Airlines, All Nippon Airlines, United Airlines, Korean Airlines, Jin Air, Asiana Airlines, and EgyptAir fly Boeing 777s using PW4000 engines. Therefore, the extent of a potential grounding of the aircraft type will not have the reach and extent of the Boeing 737 MAX crisis, which saw worldwide airlines crippled due to the unexpected and massing stoppage of its backbone fleet of single-aisle jets.

This is a developing story and Airways will continue to monitor it closely. Stay tuned.


Featured Photo: John Leivaditis/Airways