The United States' Federal Aviation Administration (FAA) has issued an emergency airworthiness directive that is interim and requires that engine operators of Pratt & Whitney PW1100G-JM and PW1400G-JM geared turbofans do an ultrasound inspection of the engines’ first-stage and second-stage hubs within a month. The inspections are ordered due to concerns about cracks that could cause engine failure in flight leading the engine to fall apart.
The latest airworthiness directive was triggered due to an incident concerning an A320 powered by PW1127GA-JM engines that aborted take-off due to high-pressure compressor (HPC) 7th-stage integrally bladed rotor (IBR-7) separation where the fan blade came off of the hinges on December 24, 2022.
As per the directive: “This condition, if not addressed, could result in uncontained disk failure, release of high-energy debris, damage to the engine, damage to the airplane, and loss of the airplane. The FAA is issuing this AD to address the unsafe condition on these products.”
This led the FAA order an inspection of the first-stage and second-stage high-pressure turbines (HPTs).
In the FAA’s airworthiness directive, the FAA estimated only 20 engines on US-registered aircraft would be impacted. It is observed that Spirit Airlines will bear the maximum brunt of this inspection with an estimated financial cost of $340,000 per engine and an additional $171,000 per part if replacement is necessary.
According to the airworthiness directive, the FAA also estimated that the cost in time will be 100 work hours to conduct the ultrasound inspections and a financial cost of $170,000 per stage for a total financial cost of $340,000 per engine.
If the 1st-stage or 2nd-stage hubs need to be replaced, the cost per part will be an additional $171,000 for one hour. The FAA presumes all labor costs to be at the rate of $85 an hour.
Already seven of Spirit Airlines’ A320neos are grounded following the Labor Day weekend until the end of the year. However, inspections normally take only up to eight weeks or about two months, so the aircraft may be airworthy sooner than the end of 2023.
Going ahead, the airworthiness concerns are not limited to US-registered aircraft alone, as inspections may be required for 101 aircraft worldwide mostly, Air New Zealand, Wizz Air, and potentially IndiGo in India.
There are also ongoing problems with all Pratt & Whitney geared turbofans. On July 26, Pratt & Whitney announced that around 1,200 of the company's 3,000 Geared Turbofan (GTF) engines would have to be recalled for further inspection of microscopic cracks caused due to a rare condition in the powdered metal used to make the engines' high-pressure turbine disks.