Marines Should Reduce King Stallion Helicopter Buys Until Tech Problems Fixed, GAO Says

CH-53K King Stallion prepares to take off at Marine Corps Air Station New River
A CH-53K “King Stallion” prepares to take off at Marine Corps Air Station New River, North Carolina, Jan.14, 2021. (Christopher O’Quin/U.S. Marine Corps)

The Marine Corps should reduce the number of new heavy-lift helicopters it buys until initial operational testing is complete, a new government watchdog report finds. That recommendation is based on a track record of technical problems with the CH-53K King Stallion program that have led to schedule delays and billions of dollars in cost overruns.

The service launched the program in 2005 to replace the older CH-53E helicopter with a more powerful aircraft to transport heavy weapons, equipment and supplies from ship to shore.

A Government Accountability Office, or GAO, report released this month found that, while the Lockheed Martin-Sikorsky CH-53K program has made progress, there is a "moderate risk" that the new aircraft will not meet the required levels of reliability and payload-carrying capability by the end of operational testing.

Read More: New Executive Order Requires Pentagon to Track Military Absentee Ballots

Technical issues -- ranging from engine shutdown from exhaust gas reingestion to a flawed power distribution unit design -- resulted in a seven-year delay to the full-rate production decision from December 2015 to November 2022, the report states.

"CH-53K total program costs also increased by nearly $15.3 billion since the program began due to technical issues and a quantity increase [to] fielded helicopters from 156 to 200," according to the report.

As a result, the GAO recommends that the Pentagon prohibit the Marine Corps from buying more than six CH-53Ks per year until initial operational test and evaluation, or IOT&E, is completed.

IOT&E is slated to start operational testing in June 2021, about two years later than intended, and to be complete in 2022, the GAO states.

The Defense Department did not agree with the GAO's recommendation, according to a Pentagon response in the report.

The Marine Corps plans to buy seven CH-53Ks in fiscal 2021, 11 in fiscal 2022, 12 in fiscal 2023, 18 in fiscal 2024 and 23 in fiscal 2025.

"A reduction in planned FY2021 and FY2022 quantities poses greater risk to the viability and affordability of the production program than the risk posed by the remaining technical challenges," according to the Pentagon's response. "Additionally, there is no quantifiable data provided in the report that reasonably concludes that procuring six helicopters per year will reduce the risk of remaining technical challenges or potential concurrency issues."

The Pentagon argues that the GAO's recommendation would affect more than fiscal years 2021 and 2022.

"Reductions of one aircraft in FY2021 and five in FY2022 would require subsequent reductions in future years to reestablish a realistic, achievable production ramp rate," according to the DoD response in the GAO report. "A major reduction in procurement would cause significant cost increases from Sikorsky and its suppliers as well as significant delays to transitioning the Fleet Marine Force from the aging CH-53 E to the CH-53 K."

The new CH-53K is designed to transport external loads of more than 27,000 pounds over a range of 110 nautical miles at an altitude of 3,000 feet without refueling -- a major performance improvement over the CH-53E.

But technical issues identified during developmental testing have "delayed the start of operational testing, resulted in the extension of the development contract period of performance, and put the program at risk of not meeting some performance goals," according to the GAO report.

As of November 2020, the program had identified 126 technical deficiencies or issues with the CH-53K, the report states.

"At a higher level, some of these technical issues can affect the helicopter's airworthiness -- the helicopter's ability to safely attain, sustain, and terminate a flight within approved usage limits -- as well as sustainment costs, or performance of the helicopter," according to the report.

Program officials have a temporary fix for the CH-53's flawed power distribution unit, or PDU, according to the GAO. If left unfixed, the faulty design had the potential to have "a single point failure causing important systems to lose power," the report states.

An earlier version of the tail rotor flexbeam, which connects the tail rotor hub to the individual blades, was delaminating during flight tests. A temporary solution is now in place, according to the GAO.

The Marine Corps announced in 2019 that engineers had fixed mechanical problems on the CH-53K, including an exhaust-gas reingestion issue that resulted in the aircraft sucking dirty air back into its engine, a problem that can cause overheating and engine shutdown.

To start IOT&E, the program "determined that it must verify the steps to address 106 of 126 technical issues" identified during developmental testing, according to the GAO.

As of October 2020, the program office reported that, of those 106 issues, 75 have solutions closed, 30 are pending verification, and one has a solution being developed, the GAO states.

"Program officials also stated that the program is on track to have fixes for all 126 issues verified and closed prior to the first deployment in fiscal year 2024," according to the report.

The GAO stressed that it remains important that program management focus on resolving technical challenges that might affect the helicopter's performance before producing more of the aircraft.

"Specifically, the extension of the schedule for completion of testing in the context of a planned increase in production of CH-53K helicopters raises the risk that costs will rise to pay for retrofitting aircraft produced before testing is completed," the report states. "Increasing production beyond the current level of six per year -- in the face of unresolved technical challenges and still-to-be completed testing -- could prove costly and delay delivery of suitable aircraft to the warfighter."

-- Matthew Cox can be reached at

Related: Marines Say They've Fixed Engine Troubles on New King Stallion

Story Continues