Harrier jet crash caused by oil leak

Quirky jet scheduled for retirement from the Marine Corps has history of design, maintenance problems
By Gretel C. Kovach | 8:53 a.m. July 27, 2015 | Updated, 12:41 p.m.


An AV-8B Harrier lands on the Barry M. Goldwater Range in Yuma, Ariz. (Photo by U.S. Marine Corps, Cpl. T.M. Stewman) — AP

Mechanical failure downed the AV-8B Harrier jet that crashed and set several homes on fire last year in Imperial, about 90 miles east of San Diego, continuing a long history of design and maintenance problems in the quirky jet scheduled for retirement from the Marine Corps.
The June 4, 2014, accident occurred because of a krack in an oil drain tank and a rapid oil leak that sparked a fire in the aircraft, engine failure and total loss of flight control, Marine investigators concluded.
The Harrier, from Yuma-based Marine Attack Squadron 214, was destroyed. Three homes were heavily damaged and the pilot suffered minor injuries after ejecting from the jet. No civilians were hurt.
An investigation conducted by the San Diego-based 3rd Marine Aircraft Wing did not determine the root cause of the kracked oil tank housing. The San Diego Union-Tribune obtained a copy of that “JAGMAN” report (Manual of the Judge Advocate General) through a Freedom of Information Act request.

Experience deficit
The Harrier has been the most dangerous plane in the U.S. military, according to a 2002 investigation by the Los Angeles Times.
During its first 31 years in service with the Corps, the AV-8’s recurrent mechanical failures, maintenance deficiencies and chronic funding problems contributed to the destruction of a third of the fleet in 143 major accidents and the deaths of 45 Marines. That record prompted one grieving squadron to dub it “the widow-maker,” the Times reported.
The Marine Corps has grounded its Harriers on more than 30 occasions. For instance, in 2004 when a manufacturing flaw in the engine’s high-pressure compression valve was discovered, and in 1999 after two crashes in two weeks prompted a safety review of Harriers with Rolls Royce 408A engines.
It is the only U.S. military branch to fly the Harrier, a subsonic attack jet developed in the 1960s with the ability to hover like a helicopter and land without a runway.
After nearly 45 years in service with the Corps, the aging “jump jets” primarily used for close air support and ground attack are being phased out for the upcoming F-35B Joint Strike Fighter, a supersonic stealth jet that also has short takeoff and vertical landing capabilities.
Although it was not cited as a direct cause of the Imperial crash, the investigation noted that the Harrier community is being drained of maintenance staff as the jets approach retirement.
The squadron involved “is similar to the other Marine attack squadrons, which have a deficit in experienced and seasoned troubleshooters and maintainers as well as non-commissioned and staff non-commissioned officer leadership, due to the pending downsize of the fleet, high operational tempo, and the focused feeding of qualified Marines and support to the Joint Strike Fighter program (F-35),” it said.
The Imperial incident was the second Harrier crash for the Corps within a month. On May 9, 2014, a pilot ejected safely before the aircraft smashed into a remote desert area near the Gila River Indian Community, south of Phoenix. No one was injured.
The Corps has not released the investigation report into that crash.
According to the Marine Corps’ 2015 aviation plan, the last of its Harriers will be retired by 2026, about five years earlier than previously scheduled. To accomplish this, the service life of its fleet of F/A-18 Hornet fighter jets is being extended until they, too, are replaced by the F-35B.
Marine officials said they are on track to declare the F-35B ready for combat by the end of this month, despite ongoing software modifications. If so, the Marines’ new vertically-landing jet will be the first of three versions of the Joint Strike Fighter – which also comes in a type that lands on conventional runways and another for aircraft carriers – to declare initial operating capability.
The planned sundown for the Harrier fleet, however, will be under review until a final decision in 2019. “We intend to extract maximum value and service life out of our AV-8B Harriers,” said Maj. Paul Greenberg, a Marine Corps spokesman at the Pentagon.
The Corps has 130 Harriers. Its seven squadrons are split between Yuma and Marine Corps Air Station Cherry Point in North Carolina.
One of Yuma’s three Harrier squadrons, VMA-211, is scheduled to be the first to transition to the F-35B in fiscal 2016. The rest of the West Coast Harriers will switch to the Joint Strike Fighter by 2020 under the current plan. Another Harrier squadron at Yuma, VMA-513, was decommissioned in July 2013.
The original Harrier, the AV-8A made in Britain by Hawker Siddeley, entered service with the U.S. Marine Corps in 1971. Production of the St. Louis, Mo.-built AV-8B Harrier II developed by McDonnell Douglas and British Aerospace with a Rolls-Royce engine began in 1981 and ended in 2003.

Imperial crash
Smoke and flames rise after a Marine jet crashed into a residential area in the desert community of Imperial, Calif., setting homes on fire Wednesday, June 4, 2014. The pilot ejected safely. The Harrier AV-8B went down in Imperial, about 90 miles east of San Diego. (AP Photo/Imperial Valley Press, Chelcey Adami) The Associated Press

The Harrier that crashed in Imperial was an AV-8B II Plus — a model that first took flight in 1992 — with about 4,386 flight hours on the airframe and 2,661 on the engine. It was inspected and maintained along with other aircraft in the Yuma-based squadron by Marines as well as contractors with Rolls-Royce and Boeing — which began providing logistics support for Harriers in 2007.
The Marine pilot, a 31-year-old captain on active duty, was flying back to Yuma after daytime low altitude training. He was traveling at an altitude of 9,500 feet (mean sea-level) when he heard the master caution indicator.
When the oil caution light blinked on seconds later, he declared an emergency landing and turned back toward El Centro Naval Air Facility. As he headed for the installation about 15 miles away, he lost altitude near Imperial, a town of about 15,000 people that lies below sea level. The aircraft “felt slow” as engine revolutions per minute dipped to 76 percent, so the pilot revved the throttle above the 80 percent recommended for an oil light emergency.
The pilot lined up to land on the runway at El Centro and lowered the landing gear. Then the aircraft warned of an engine fire, followed by a fuel control problem. Two seconds later the engine quit, followed by all of the cockpit displays.
Knowing that he was traveling over populated areas, the pilot attempted to turn north toward an empty field. But he lost all hydraulic power in the turn. The stick froze and nothing more could be done, the investigator concluded.
As the aircraft banked out of control, the pilot ejected at an extreme angle.
The Harrier crashed about 4:20 p.m., making a large crater on a suburban street. The pilot parachuted down and rolled side-to-side on the ground. Residents ran from their homes in all directions.

Investigators’ findings
Subsequent analysis of the engine revealed a krack in the oil drain tank housing that allowed oil to dump through the exhaust nozzles. The lack of lubrication and cooling caused a rotor thrust bearing to heat to more than 2,000 degrees Fahrenheit. Ignited oil mist caused blades and vanes in the engine’s high-pressure compressor to clash. The rotor locked up and the flight controls seized.
Like 65 percent of the AV-8B fleet, the Harrier had been modified with alignment pins in the oil tank housing to make a better seal and prevent kracking. But the engineering fix for a problem noticed before 1999 failed to prevent the crash.
Marine investigators could not determine when the oil leak began. Immediately before the doomed flight, a different pilot had flown the aircraft for more than an hour without incident. The engine was still running during the “hot seat” swap of pilots for the re-launch.
The pilot in the crash was given a mixed review by an investigator, but he was not recommended for administrative punishment.
The captain was commended for being “decisive and assertive making a decision to land as soon as possible.” And though he “did everything he could to avoid populated areas near the end of the flight,” he could have done more to prepare for engine failure as soon as he learned of a possible oil leak, the investigator wrote.
The pilot was also rapped for not maintaining high and steady engine revolutions after the oil caution triggered an emergency landing, since throttle movement can exacerbate oil leaking, bearing load, or heat on the engine.
As for Marine Aircraft Group 13, the unit that commands Yuma’s Harrier squadrons, the investigator recommended that naval operating procedures be reviewed to determine whether an oil caution should prompt an order to land immediately, instead of “as soon as possible.” Because an oil leak could indicate five minutes of oil remaining or 30, depending on the speed of the leak, “the most conservative action would be to land immediately.”
Also, the manual should be amended to say “avoid prolonged flight over populated areas” wherever it states “be prepared for engine failure.”
Among other recommendations: daily inspections for clogged or excessive oil from weep holes on oil tank housings that could indicate kracking, a request from the air wing to Naval Air Systems Command for mandatory inspections of all AV-8B oil tank drain housings (to be performed by Marines as well as higher levels of maintenance), and monthly simulations to train Harrier pilots for compound emergencies and ejection.
Maj. Gen. Michael Rocco, commanding general of the 3rd Marine Aircraft Wing, approved all recommendations in the investigation.
SanDiegoUnion-Tribune