Pilot error and a malfunctioning Collins Aerospace‘s [RTX] Advanced Concept Ejection Seat II (ACES II) contributed to a June 30 fatal crash of a Lockheed Martin [LMT] F-16CM at Shaw AFB, S.C., per an Air Combat Combat Command (ACC) Accident Investigation Board (AIB) report.

32-year-old Air Force 1st Lt. David Schmitz, assigned to the 77th Fighter Squadron at Shaw, was piloting the F-16CM during his first nighttime suppression of enemy air defenses training flight and his first attempt at air-to-air refueling from a Boeing [BA] KC-135, ACC said.

After an unsuccesful attempt at pre-strike refueling, Schmitz, accompanied by the flight leader of the four-ship formation, turned back to the airfield.

“During the final approach to landing, Lt. Schmitz’s aircraft struck the localizer antenna array short of the runway threshold, severely damaging the left main landing gear,” ACC said. “The aircraft briefly touched down and executed a go-around. Based on the damage to the aircraft and the anticipated directional control problems that would occur during any subsequent landing, it was decided to attempt an approach-end cable arrestment. However, the aircraft’s tail hook did not catch the cable, and because the left main landing gear was damaged the left wing contacted the runway. The pilot ejected from the aircraft, but an ejection seat malfunction resulted in his parachute never deploying. Lt. Schmitz impacted the ground while still in the seat and died instantly.”

The AIB report said that “the cause of the mishap was the MP’s [mission pilot] failure to correctly interpret the approach lighting system (ALS) and identify the runway threshold during his first landing attempt, which resulted in severely damaged landing gear.”

“Additionally, I find by a preponderance of evidence two factors substantially contributed to the mishap: (a) the SOF [supervisor of flying] chose not to consult the aircraft manufacturer, which resulted in the decision to attempt a cable arrestment in lieu of a controlled ejection and (b) a series of ejection seat malfunctions occurred, which resulted in the MP impacting the ground while still in the ejection seat,” per the report written by Air Force Maj. Gen. Randal Efferson, president of the AIB.

The supervisor of flying’s “decision to not call the aircraft manufacturer for technical assistance directly resulted in a decision to attempt an approach-end cable arrestment with less than favorable conditions in lieu of a controlled ejection,” the report said. “Specifically, the Air Force, in coordination with Lockheed Martin, provides a dedicated hotline that an F-16 SOF, at any location around the world, can call for technical assistance when experiencing an in-flight emergency (IFE), which may not be specifically addressed in the pilot checklist. The program is known as the Conference Hotel (CH) procedure and was available at the time of the mishap. Following initial damage, the MA [mission aircraft] had more than thirty minutes of fuel remaining to troubleshoot the problem, so I assess there was time available to seek CH assistance.”

The ACES II ejection seat has three modes of operation, one of which is automatically engaged, depending on aircraft speed and altitude, when a pilot begins an ejection.

“Mode 1 operation is for relatively low speeds and altitudes,” per the AIB report. “Modes 2 and 3 are for progressively higher altitudes and/or airspeeds. The MP initiated an ejection on the runway, in approximately 16 degrees of left bank and 129 nautical miles per hour (knots), resulting in a Mode 1 ejection sequence. Post-mishap analysis confirmed that these parameters are within the performance envelope for the ACES II and should have resulted in a successful ejection sequence.”

During the Mode 1 ejection, “six pyrotechnic devices should have fired, yielding a parachute in less than two seconds, but the devices did not fire,” the report said. “Preliminary analysis indicates that the thermal batteries providing power to the DRS [digital recovery sequencer] reached sufficient temperature, but no DRS initiated events occurred. DRS actuated pyrotechnics sequence actions are required to stabilize the seat during ejection, deploy the recovery parachute, and separate the crewmember from the seat.”

A “somewhat similar DRS failure” occurred on Oct. 20, 2014, when a Tulsa Air National Guard F-16C pilot ejected near Moline, Kansas, Jefferson wrote. In that incident, which resulted in minor injuries to the pilot, the DRS sent firing signals to stabilize the ejection seat, but the separation of the pilot from the ejection seat and parachute deployment did not occur. The pilot, however, was highly experienced and ejected at a significantly higher altitude–7,500 feet AGL.  The pilot “was able to recognize the failure, and pull the EMPDH [emergency parachute deployment handle], thus separating him from the seat and deploying his parachute.”

After the Kansas crash, the Air Force issued a time compliance technical order (TCTO) 11P2-3-502, Installation of the Shorting Plug on the DRS Electronic Module on Jan. 20, 2016 to eliminate noise bias that can prevent the proper functioning of DRS, a three channel system that requires at least two channels to be in accord to work.

“Channel three noise bias issues have been observed in approximately 9% of all live ejections and sled tests,” the report said. “TCTO instructions allowed for installation of the shorting plug during regularly scheduled 36-month maintenance/inspections.”

The first opportunity for the installation of the shorting plug on Lt. Schmitz’s F-16CM was in August, 2017–the regularly scheduled 36-month ejection seat maintenance/inspection interval, “but TCTO shorting plug parts were not available, so the next installation date was moved three years to August 2020,” the report said.

“In addition, the ten-year shelf/service life of the DRS installed in the MA expired in February 2019, but received three temporary service life extensions, extending it to 31 July 2020,” per the report. “All extensions were coordinated and approved by the Air Force Life Cycle Management Center. There was a small window of opportunity to replace the MA DRS in May 2020 with a newer system, which replaces the DRS and does not require a TCTO shorting plug. The newer system, known as the Modernized ACES II Seat Sequencer (MASS), became available in May 2020, but in order to consolidate maintenance actions, a request was granted to move the MASS installation to the July-August 2020 timeframe. Engineers have assessed that the MA’s DRS had critical failures in both channel two and three. Therefore, ejection seat engineers have confirmed that earlier installation of the TCTO should have prevented the channel three noise issue, allowing channel one and three to communicate normally, so the ejection seat would have functioned properly.”

Jefferson wrote that he believed that “a lack of available parts resulted in delayed implementation of the TCTO designed specifically to address the ejection seat failure, which occurred during this mishap.”

Air Force Gen. Mark Kelly, the head of ACC, said in a statement that the AIB report “identified a sequence of key execution anomalies and material failures that resulted in this mishap.”

“For example, in order to account for the increased demands and pilot workload involved with night flying, Air Force Instructions mandate pilots demonstrate proficiency in events like aerial refueling in the daytime before attempting them at night,” he said. “That didn’t occur for this officer, and when we have oversight breakdowns or failures of critical egress systems, it is imperative that we fully understand what transpired, meticulously evaluate risk, and ensure timely and effective mitigations are in place to reduce or eliminate future mishaps.”