NTSB Factual Report

HISTORY OF FLIGHT

On March 11, 2015, at 1149 mountain standard time, a BAe Systems Hawk MK-67, N506XX, call sign BADGER1, collided with a truck during takeoff from the Yuma Marine Corps Air Station (MCAS)/Yuma International Airport (KNYL), Yuma, Arizona. The airplane was owned by Air USA, Inc., and operated as a public aircraft flight in support of the United States Air Force (USAF). The airline transport pilot and pilot-rated passenger were not injured. The driver of the truck sustained fatal injuries. The airplane sustained substantial damage during the accident sequence. The local area flight departed Yuma at 1148. Visual meteorological conditions prevailed, and a Military visual flight rules flight plan had been filed.

The airplane was being utilized along with a second similarly equipped Hawk (callsign BADGER2) by Air USA in support of the USAF as part of the Special Operation Terminal Attack Controller Course (SOTACC). They were performing a 15-second staggered takeoff, and their mission was to provide close air support (CAS) for the training of Joint Terminal Attack Controllers (JTAC's). The airplane was equipped with external fuel tanks on the inboard pylon of each wing, and bomb rack/dispensers loaded with practice ordinance attached to the outboard wing pylons.

At the time of the accident, a construction crew from the United States Marine Corps (USMC) was preparing a concrete pad at the left edge of runway 03L in preparation for the installation of an expeditionary arresting gear system. The pad was located 10 feet from the runway edge, about 6,500 feet from the runway 03L landing threshold. The construction operation, which included support vehicles, crew, and construction equipment, occupied the space from the runway pad outwards about 150 feet. The truck that was struck was located 140 feet beyond the runway edge, and was occupied by a Marine Lance Corporal who was providing operational escort and safety support for the construction crew.

The pilot reported that the preflight, engine start, taxi, and line-up on runway 03L were uneventful. The airplane was positioned on the right side of the runway, with BADGER2 positioned as the wingman to the left and aft. The pilot stated that once cleared for takeoff, he applied engine thrust and the engine spool-up, takeoff roll, and acceleration check speeds were as expected. He stated that he felt the airplane's nose wheel become light about the time they reached rotation speed. The nose of the airplane then lifted, and a short time later the main wheels became airborne. The left wing then dropped, and the nose yawed about 10 degrees to the left. He attempted to maintain a low angle of attack, applying slight rudder and aileron corrections. He considered aborting the takeoff, but due to the airplane's angle relative to the runway he was concerned the airplane might tumble if they entered the undulating adjacent terrain. He continued to apply corrective control inputs, but the airplane did not respond in a positive manner as he expected, and the left drift progressed. The airplane continued to bank left and then right, with the main landing gear and bomb dispensers striking the adjoining shoulder multiple times. The airplane was now flying directly over the gravel shoulder, about 100 feet left of the runway edge, when the construction crew came into view. The right wing struck the truck, and the airplane yawed to the right, coming to rest on the shoulder, about 650 feet beyond the point of impact. The truck came to rest about 160 feet beyond the point of impact.

PERSONNEL INFORMATION

The pilot held an airline transport pilot certificate with ratings for airplane single-engine and multiengine land along with type ratings, authorized experimental aircraft: AV-L39, Hawk. He held a first-class medical certificate issued on August 7, 2014; it had no limitations or waivers.

At the time of the accident, the pilot was a current and active A-10 pilot for the Air National Guard. The A-10 is a twin-engine, straight-wing, close air support airplane utilized by the USAF.

His aviation career began in 2000, initially as crew chief for the A-10; in 2008 he was commissioned to fly the A-10, having received training in both the T-37 and T-38. In March 2014 he began working as a contractor for Air USA, flying the L39.

The pilot reported a total flight experience of 2,116 hours, the majority of which (about 1,500 hours) took place in Tactical Jet aircraft, and primarily in the A-10. His total flight experience in the 12 months prior to the accident was 328 hours, and his total experience in the Hawk was 67 hours, with 55 as pilot-in-command. His last Federal Aviation Administration (FAA) checkride took place on January 19, 2015, and was for his airline transport pilot certificate.

The pilot's experience with the Hawk was gained exclusively while at Air USA, where he began his Hawk training in August 2014. The training was composed of flight manual study, followed by 2 days of ground school, cockpit familiarization, and ejection seat training. He then flew three graded instructional flights including five cross-country flights to establish basic and advanced aircraft handling along with instrument procedures, after which he was cleared to take the checkride for type rating with an FAA designated pilot examiner (DPE). Having gained his type rating, he went on to receive further instruction gaining initial qualification, mission qualification, air-to-ground qualification, and flight lead upgrade training, and after about 12 hours of total flight time, he was approved by Air USA to fly solo missions. Documentation provided by Air USA revealed that he scored 100 percent on all written examinations, and during air-to-ground training received the following comments, "Had some A-10 pilot tendencies during tight turns," "Has adjusted to the increased speed of the Hawk very well."

Air USA was the only private operator of the Hawk in the United States, and as such, the FAA DPE who performed the pilot type rating checkride did not have direct experience flying the Hawk. (The United States Navy operates the T-45 Goshawk, which is a Hawk variant).

The pilot-rated passenger was not an employee or contractor for Air USA. He had flown on the two previous missions with the pilot in the accident airplane, and was flying as a potential future pilot for Air USA in a "ride along" capacity.

AIRPLANE INFORMATION

The Hawk MK-67 was a swept-wing, two-seat, advanced trainer/light attack airplane, powered by a single Rolls-Royce Adour turbofan engine. The accident airplane was manufactured in 1992 by BAe Systems in the UK as part of a group of 20 Hawks configured specifically for export to the Republic of Korea Air Force (ROKAF). The airplane was then utilized by the ROKAF for training until it was sold to Air USA, along with 11 other Hawk MK-67's in September 2013. The sale included documentation for the fleet, along with a series of spare parts. The airplane was subsequently exported to, and registered in, the United States, where it was issued a special airworthiness certificate by the FAA in the experimental/exhibition category in March 2014.

The later variants of the Hawk remain in production, with over 900 built since 1974.

Maintenance

Maintenance was performed in-house by Air USA mechanics on a continuous airworthiness basis, utilizing an OEM (original equipment manufacturer) inspection program. At the time of the accident, the airplane had accrued a total flight time of 5,625.3 hours. The engine total time was 3,782.7 hours, with the last overhaul occurring 155.7 flight hours prior.

Fuel System

The airplane's fuel system was comprised of an internal fuselage bag tank connected to integral wing tanks, with a total system capacity of 3,006 pounds. Two wing-mounted external "drop" tanks, mounted to the inboard wing pylons, increased fuel capacity by an additional 1,078 pounds per side. Fuel flowed from each external tank to the fuselage tank, and during transfer the integral tank system was automatically kept above 2,400 pounds until the external tanks were empty.

The external tanks structural integrity was maintained through a series of internal ribs and stringers; the tanks did not contain baffles, and the fuel was free to move within the tanks during flight. The external tank fuel quantities were the subject of handling and maneuvering limitations in-flight, but no limitation existed regarding the fuel quantity held in the tanks during takeoff. The airplane's flight manual, "External Wing Fuel Tank - Limits" section noted the following, "10 seconds of straight-and-level flight is recommended before jettison to permit the fuel contents to stabilize."

The accident pilot reported that the Hawk was the only airplane he had flown that does not place limitations on partially filled external tanks during takeoff, and that in his experience, takeoff with partially filled tanks is not recommended due to the increased sensitivity of pitch control, decrease in lateral directional control at low speeds, and the potential for tank damage. A BAe test pilot was interviewed during the investigation. He stated that although there are no external tank quantity limitations for takeoff, his personal practice is to always takeoff with the external tanks either full or empty, so that should they need to be jettisoned during departure, they will fall from the airframe in a predictable manner. The Air USA Chief Pilot reported that 75 percent of all Air USA missions were conducted with the external tanks partially filled at takeoff, and that they had no previous issues.

The airplane had been experiencing intermittent external tank fuel transfer problems in early February 2015, when it was performing live fire exercise for the USMC in North Carolina. The external tanks were not consistently transferring fuel automatically to the internal tanks, and the airplane was flown to Air USA's primary maintenance facility in Quincy, Illinois, on February 13 for further diagnosis. Maintenance personnel replaced the internal tank high level float switch and refuel valve, and the airplane was placed back into service on February 20. During the repositioning flight from Quincy to MCAS Yuma, the external tanks again failed to transfer, so the pilot diverted to Salinas, Kansas. During the descent, the tanks started to transfer, and upon landing the transfer to the internal tank was complete. The pilot refueled the external tanks with 500 pounds of fuel per side, and flew to MCAS Yuma uneventfully.

The airplane was not flown again until the day prior to the accident. On that morning (March 10), mechanics performed a pre-flight inspection, and serviced the airplane with fuel. The airplane flew two uneventful missions that day with fuel transferring normally from the partially filled external tanks. The third flight was a night mission, and was flown by the accident pilot. The airplane departed with full fuel; however, the external tanks again would not transfer, so he ended the mission early, returning with about 1,000 pounds of fuel in the internal tanks, and about 1,000 pounds in each external tank.

On the morning of the accident, the Chief of Maintenance performed a ground run with the airplane in order to duplicate the transfer problem. The system operated normally, and after additional troubleshooting steps he concluded that the problem was still most likely an intermittent high level float switch in the internal tank. He instructed the ground crew to disconnect and secure the external tank transfer valves (commanding the valves to the normally open position, thereby allowing fuel to transfer directly to the internal tank). He briefed the pilot of the findings, advising him that the tanks may still not transfer, and he fueled the internal tanks to 3,000 pounds, and left the external tanks with about 600 pounds in each.

METEOROLOGICAL INFORMATION

An automated surface weather observation for MCAS Yuma was issued 8 minutes after the accident. It indicated variable wind at 3 knots, 10 miles or greater visibility, with scattered clouds at 12,000 ft, broken clouds at 18,000 ft and 25,000 ft, temperature 27 degrees C, dew point 01 degrees C, and an altimeter setting at 30.06 inches of mercury.

AIRPORT INFORMATION

The majority of MCAS Yuma, including all runways, is owned, operated, and governed by the Department of Defense (DoD), and operated as a "shared use" airport with Yuma County Airport Authority (YCAA)/Yuma International Airport, who maintain an FAA Part 139 Certificate.

The Department of the Interior granted an easement for public airport purposes in 1956 to the facilities YCAA, thereby granting the right to use the airport for the landing, takeoff, and parking of civilian aircraft in common with aircraft owned and controlled by the government. The YCAA and MCAS Yuma are entirely separate organizations, and there is no owner/tenant relationship. As such, the airport is considered a "shared use" facility rather than "joint use."

The airport is primarily operated in accordance with the MCAS Yuma Station Order P3710.4L W/CH 5, Airfield Operations Manual. Conversely, YCAA operates in accordance with an FAA Approved Airport Certification Manual (ACM). The two entities coordinate operations via a series of letters of agreement (LOA), and although there is no requirement for MCAS to meet FAA part 139 requirements, according to the agreements, they do to "the extent possible."

The airport is composed of four runways, with the majority of civilian aircraft operations occurring on runways 8/26 and 17/35. The two longer "tactical" runways 3L/21R and 3R/21L are equipped with arresting systems, and used primarily for military operations.

The FAA Advisory Circular 150/5370-2f defines a runway safety area (RSA) as a surface surrounding the runway prepared or suitable for reducing the risk of damage to airplanes in the event of an aircraft undershoot, overshoot, or excursion. Construction is generally not permitted within an RSA while the runway is open, although the temporary use of declared distances and/or partial runway closures may provide the necessary RSA under certain circumstances.

The DoD Unified Facilities Criteria (UFC) 3-260-01, "Airfield and Heliport Planning and Design" utilize a different set of criteria for runway and taxiway design, and no specific RSA environment exists. Instead the term "primary surface" is utilized to define the areas both including and immediately adjacent to runways. Examination of Station Order P3710.4L W/CH 5 and UFC 3-260-01 did not reveal any prohibitions to performing work on the primary surface while the runway was in operation, nor was there any requirement that a notice to airman (NOTAM) be issued advising of such operations, and no NOTAM was issued at the time of the accident.

Construction Crew

The construction crew consisted of about 20 workers, accompanied by 5 vehicles. The vehicles included two "7-ton" dump trucks, a "7-ton" large flatbed cargo truck, a back hoe loader, an M1152 "high back" high mobility multipurpose wheeled vehicle. Also present were a generator, hydroseeder, and an engineering equipment trailer.

MEDICAL AND PATHOLOGICAL INFORMATION

The pilot, along with the mechanic who worked on the airplane that day, voluntarily submitted for both breath alcohol and urine drug toxicological testing at 1615 on the day of the accident. The results were negative for all screened drug substances and alcohol.

SURVIVAL ASPECTS

The pressurized cabin structure was not compromised, and the crew was able to open the canopy unhindered after the airplane came to rest. The airplane was equipped with ejection seats; however the pilot elected not to utilize them out of concern that the airplanes bank angle while still close to the ground would put them into an unsafe ejection profile.

TESTS AND RESEARCH

The pilot-rated passenger, positioned in the rear seat, had mounted a GoPro Hero HD1 digital video camera to the right inner side of the canopy, adjacent to his head. The camera captured the entire accident sequence.

Airframe and Engine Examination

Examinations of the airframe and engine were performed in the presence of the NTSB IIC, and tec

NTSB Probable Cause

The pilot’s initiation of an early rotation during takeoff, which led to an aerodynamic stall and loss of airplane control. Contributing to the accident were the pilot's use of noseup pitch trim and the operator's policy to use nose-up pitch trim during takeoff and the lack of oversight of the operator by the US Air Force. Contributing to the severity of the accident were US Marine Corps airport policies that allowed construction activities immediately adjacent to an active runway, which resulted in the airplane's collision with a truck.