New FAA AD On Pratt & Whitney PW1100G Engines Could Cost US Airlines +$150 Million

Summary

• The FAA has issued a new directive due to a powdered metal anomaly detected in a high-pressure compressor (HPC) part.
• The directive affects 430 engines in the US, according to the agency’s estimates.
• Operators must comply with inspection and replacement timelines outlined in the AD, which has an effective date of April 11, 2024.

The Federal Aviation Administration (FAA) has issued a new directive for the Pratt & Whitney PW1100G engine, also known as the Geared Turbofan (GTF), one of the two options for the Airbus A320neo aircraft family. The airworthiness directive (AD) also affects the PW1400G engine, which was supposed to power the Russian-made MC-21.

Prompted by an engine failure

According to the FAA, the latest AD follows supersedes two previous directives. Pratt & Whitney’s analysis of a failure of a high-pressure compressor (HPC) 7th-stage integrally bladed rotor (IBR–7) led the company to conclude that a powdered metal anomaly caused the incident in December 2022, prompting the regulator to issue the new directive since the anomalies were similar to another engine failure.

The previous engine failure resulted in the FAA issuing an AD (AD 2022–19–15) in October 2022, which required operators to perform an ultrasonic inspection (USI) of the high-pressure turbine (HPT) 1st-stage disk and HPT 2nd-stage disk. Depending on the results of the inspections, operators could have needed to replace either of the disks.

That directive was followed up by AD 2023–16–07, issued in August 2023. Following an updated analysis by Pratt & Whitney, the FAA warned that specific HPT 1st-stage hubs and HPT 2nd-stage hubs were susceptible to failure much earlier than previously determined. Nevertheless, the latest AD warned that,

“The analysis concluded that there is an increased risk of failure for additional powdered metal parts in certain powdered metal production campaigns, including the HPC IBR–7 and HPC IBR–8, and that all affected parts are susceptible to failure significantly earlier than previously determined.”

Correcting part removal timelines

AD 2023–16–07 was issued following an engine failure that happened on December 24, 2022. According to records by the Aviation Safety Network (ASN), one Viva Aerobus Airbus A320neo, registered as XA-VIO, suffered an engine failure during takeoff on that day, prompting the flight crew to abandon their takeoff run.

The FAA’s latest directive said that the unaddressed condition could result in an uncontained hub failure, release of high-energy debris, damage to the engine, damage to the aircraft, and loss of the airplane. The effective date of the FAA’s latest directive is April 11, 2024.

However, the regulator was forced to adjust the compliance times for the directive. Initially, the FAA published a notice of proposed rulemaking (NPRM) on December 12, 2023. Pratt & Whitney informed the United States-based agency that an error in the NPRM had significantly later removal timelines for certain HPT 1st-stage and HPT 2nd-stage hubs.

Extending inspections

The FAA detailed that in addition to keeping the required inspections of HPT 1st-stage and HPT 2nd-stage hubs and necessary replacements, the new directive will add angled ultrasonic inspection (AUSI) for HPC IBR–7 and HPC IBR–8 to identify cracks and prompt necessary part replacements.

At the same time, the directive will require airlines to conduct accelerated replacements of HPC IBR–7, HPC IBR–8, HPC rear hub, HPT 1st-stage hub, HPT 1st-stage air seal, HPT 1st-stage blade retaining plate, HPT 2nd-stage hub, HPT 2nd-stage blade retaining plate, and HPT 2nd-stage rear seal.

In total, 14 stakeholders commented on the NPRM, including airlines such as Air New Zealand, All Nippon Airways (ANA), Delta Air Lines, Hawaiian Airlines, HK Express, IndiGo, JetBlue, airlines within the Lufthansa Group, United Airlines, Vietnam Airlines, and two maintenance organizations, including Lufthansa Technik.

The FAA highlighted that the Air Line Pilots Association, International (ALPA) urged Pratt & Whitney to come up with measures to minimize the operational impact that the newly added inspections will have on operators. Still, the union supported the proposed directive without change.

Over 400 affected engines in the US

According to the regulator, the directive applies to 12 different types of PW1100G engines, as well as six PW1400G types, affecting engine parts with certain part numbers (P/N). The FAA estimated that 430 engines in the US will be affected by the directive, 366 of which will need HPT 1-st stage hub removals, 351 will need replacements of HPT 2-nd stage hubs, 408 engines will need new HPC IBR-7s, 368 will need HPC IBR-8 replacements, and 283 engines will need to have their HPC rear hubs removed.

The FAA detailed that Group 1 engines are PW1122G–JM, PW1124G1–JM, PW1124G–JM, PW1127G–JM, PW1127G1–JM, PW1127G1A–JM, PW1127G1B–JM, and PW1127GA–JM engines, while Group 2 engines are PW1129G–JM, PW1130G–JM, PW1133G–JM, PW1133GA–JM, as well as the six PW1400G models.

Per ch-aviation data, there are 772 aircraft with Group 1 engines that are either active, stored, or in maintenance, assigned to 43 different airlines. Seven aircraft do not have any operators assigned to them, which includes three former Go First Airbus A320neos.

Meanwhile, the site’s data showed that 45 airlines have 738 A320neo aircraft with Group 2 engines, including four that have no operator, with two of them being formerly operated by Vietjet. One previously belonged to China-based Qingdao Airlines.

Different AUSI compliance times

The FAA detailed that operators have to perform AUSIs on Group 1 engines if such an inspection was not done before the effective date of the directive, before accumulating 3,800 cycles since new (CSN), or within 100 flight cycles (FC) after the effective date of the directive, whichever occurs later. Repetitive inspections are mandated at each HPT engine shop visit or before exceeding 3,800 FC.

For operators with Group 1 engines that had done AUSIs before the effective date of the AD, the next inspection should be conducted at the next HPT engine visit, with the FAA warning to not exceed 3,800 FCs since the previous AUSI or within 100 FCs after the effective date of the directive, whichever occurs later. Subsequent inspections are identical to the conditions outlined for Group 1 engines without inspections prior to the effective date of the AD.

Meanwhile, Group 2 engines have the same AUSI compliance times. The only difference is that operators have to perform inspections either before accumulating 2,800 CSN or not exceeding 2,800 FCs since the engine was last inspected. Repetitive inspections are similar to those of Group 1 engines, but operators cannot exceed 2,800 FCs from the last AUSI.

Part replacements shortly after the AD’s effective date

The AD also mandates part replacement times for Group 1 and Group 1 engine HPT 1st-stage and HPT 2nd-stage hubs, with differentiating cycle limits for engines inspected before the effective date of the directive.

As such, operators of Group 1 engines that performed an AUSI before the effective date of the AD have to replace the HPT 1st-stage hub before exceeding 3,800 FCs since the last AUSI. Replacement of the HPT 2nd-stage hub is mandated before exceeding 3,800 FCs or before accumulating 7,000 CSN, whichever occurs first. If no AUSI was performed before the April 11 deadline, both hubs must be replaced before accumulating 3,800 CSN.

Meanwhile, Group 2 engines have the exact replacement conditions for both HPT hubs, except that operators have to replace them either before exceeding 2,800 FCs since the last inspection or within 2,800 CSN if the engine was or was not inspected, respectively.

The FAA has also outlined compliance times for the replacement of other parts, including the HPC rear hub, HPC IBR-7, HPC IBR-8, and both HPT hubs for Group 1 and Group 2 engines. The FAA’s compliance times are outlined below.

Cost estimates

In line with other ADs, the FAA has provided cost estimates for AUSIs and the replacement of the affected parts for US-based operators. The regulator noted that some of these costs could be covered by Pratt & Whitney’s warranty, reducing the financial impact for airlines.

Nevertheless, the AUSI of HPT 1st-stage hub, HPT 2nd-stage hub, HPC IBR–7, and HPC IBR–8 for cracks was estimated to take 80 work hours, meaning that per aircraft, an inspection would cost $6,800, totaling $2.9 million for US-based operators.

The replacement of the HPT 1-st stage hub and HPT 1-st stage hub totals $56,850 and $62,850 per aircraft, respectively, split between labor and parts costs. The FAA estimated that an HPC IBR-7 and HPC IBR-8 replacement is $82,850 and $93,850, respectively, which includes parts and labor. Fitting a new HPC rear hub is the most costly procedure, with the incurred expenses per aircraft being $132,850, according to the regulator’s estimates.

Previous financial and operational impact

AD 2023–16–07 had already significantly impacted operators’ short-term plans, which included some airlines putting off their growth plans in the near term. For example, Wizz Air, which announced its Q3 FY2024 results on January 25, 2024, said that it had 33 aircraft on the ground (AOG) because of the Pratt & Whitney PW1100G inspections.

At the time, the company expected to reach a peak of 40 AOG by the end of FY2024, which ended on March 31, 2024. This included aircraft that had been grounded since September 2023, with the low-cost carrier maintaining assumptions that, on average, the expected shop visit time needed to return engines back to service was around 300 days.

However, the most alarming metric was that Wizz Air had expected that its capacity, measured in available seat kilometers (ASK), would be flat year-on-year (YoY) during the upcoming financial year, which will end in March 2025.

In its Q3 FY24 presentation, Ryanair warned that short-haul capacity would be constrained in Europe for the next three years. While this could be because of the ever-continuing consolidation in the continent and aircraft delivery delays, the Pratt & Whitney engine issues will also have an impact, providing plenty of opportunities for the Irish low-cost carrier and its Boeing 737-based fleet, according to its financial filing.

Compensations for customers

Notably, Wizz Air was not the only airline within Europe, or globally, for that matter, that has felt the impact of the powdered metal issue of the PW1100Gs. Lufthansa Group’s latest annual report highlighted that it was increasingly confronted with the risks associated with the PW1100G engines, saying that these issues also extend to the Airbus A220 family, powered by the PW1900G engines.

“This problem entails the risk of operating interruptions, a shortage of spare parts and higher maintenance costs for the airlines in the Lufthansa Group that use these engines.”

Some carriers, like Air Astana or Spirit Airlines, have finalized agreements with Pratt & Whitney to compensate the airlines. The latter’s US Securities and Exchange Commission (SEC) filing said it entered into an agreement with the engine maker on March 26.

The agreement, which was signed with International Aero Engines (IAE), a subsidiary of Pratt & Whitney and the type certificate (TC) holder of the PW1000G engine family, will result in Spirit Airlines receiving a monthly credit through the end of 2024, subject to certain conditions. The low-cost carrier estimated that it will increase its liquidity by between $150 million and $200 million.

In response to the latest issues, Pratt & Whitney has continued to expand its repair and maintenance capacity in recent years, including more capacity for aftermarket repairs for certain components for the GTF engine in Singapore, announced in February 2024.