What happened
On 17 November 2021, an F-35B Lightning, registration ZM152, belonging to 617 Squadron RAF, was lost during flight operations while embarked on HMS Queen Elizabeth. The aircraft was part of the force deployed for Operation FORTIS. During the launch sequence from the carrier deck, the aircraft experienced a critical issue that led to an aborted launch and the subsequent ejection of the pilot.
Following the incident, the aircraft impacted the sea. An investigation later identified that an intake blank had been observed floating from the wreckage shortly after impact, suggesting the component remained within the engine inlet during flight.
The investigation
A Service Inquiry panel was convened at MOD Boscombe Down to examine the circumstances of the loss and identify contributing factors. The inquiry focused on whether the presence of the intake blank caused the accident and how such a piece of equipment could have remained in the engine.
The investigators examined the management of "Red Gear" (aircraft blanks) and the use of pin devices on the flight deck. The panel also reviewed wider organizational issues, including the tension between security requirements for fifth-generation platforms and standard aviation safety procedures. Additionally, the investigation looked into the state of the pilot's life preserver, which failed to inflate during the ejection sequence.
Findings
The investigation established that the presence of an intake blank in the engine inlet was a primary factor in the loss of the aircraft. The panel found that basic procedures for controlling equipment were not fully followed prior to the accident.
Several contributing factors were identified:
- Ineffective control and management of aircraft blanks (Red Gear) on the flight deck.
- Design issues with the equipment provided by the Lightning programme.
- A conflict between high-level security requirements (Special Access Programmes) and established safety protocols.
- Workforce challenges within the Lightning Force, including insufficient personnel, training shortfalls, and a lack of experienced engineers due to the "small force effect."
- The failure of the pilot's life preserver to inflate during the ejection, a failure pattern noted in previous aircraft accidents.
Safety action
The investigation led to recommendations regarding the management of equipment and the need for the Lightning Force and delivery teams to engage with the manufacturer to ensure all flight deck equipment is fit for purpose. Furthermore, proactive engagement with the Original Equipment Manufacturer was initiated to address the failure of the life preserver inflation mechanism.