Here is a detailed analysis of the safety protocols in case of failure of the electronic systems of a modern fighter aircraft, with specific data and examples.
The operational safety of a fighter aircraft relies on rigorous electronic redundancy. But even the most advanced mission systems, with fly-by-wire architecture, integrated sensors and multi-core inertial computers, can fail. These incidents are not science fiction, but a reality known to fighter pilots and engineers. Critical in-flight failures have already forced aircraft to make emergency returns or ejections. Faced with these risks, air forces implement structured, standardized and continuously tested protocols. This article examines these safety measures, their logic, their implementation and the leeway left to fighter pilots. Far from the marketing discourse of manufacturers, the aim here is to understand how a chain of technical decisions manages electronic failures in flight.
The protocol for managing electronic failure on board
The logic of redundancy integrated into flight systems
The electronic systems on board a modern fighter plane (Dassault Rafale, Eurofighter Typhoon, F-35 Lightning II) are designed according to a triple or quadruple redundancy architecture. The flight control system is generally fly-by-wire, without a direct mechanical link. In the event of a main computer failure, a second or third automatically takes over. The Rafale, for example, uses a triptych of digital computers (CDVE) with cross-validation. Each unit operates on an independent architecture with control algorithms fed by different sensors. If a unit deviates from the expected parameters, the system automatically deactivates it and switches to the healthy units.
Flight data (altitude, speed, orientation, angle of attack, roll rate) are constantly monitored by inertial measurement units coupled with pressure sensors and laser gyroscopes. These devices are themselves doubled or even tripled. The Rafale uses a Safran SIGMA 95L unit, combined with military GPS and realignment antennas.
The role of codified procedures in the cockpit
Each fighter pilot receives specific training in fault management procedures. These procedures, called “emergency checklists”, are integrated into the on-board system software (MFD – Multi-Function Display) but also exist in handwritten form in the cockpits. When an alarm is activated, the pilot follows a defined sequence: identification of the type of alarm, attempt to reset the circuits, manual transfer of control to secondary systems, then decision to land immediately or continue the flight according to the criticality thresholds.
The fighter plane is also capable of self-diagnosis. The F-35, for example, uses ALIS (Autonomic Logistics Information System) – replaced by ODIN since 2020 – to predict failures by cross-referencing thousands of telemetric data.
Concrete examples of failure management
During a flight in 2018, a British Typhoon experienced a failure of the inertial navigation system. The pilot switched manually to terrain radar mode to maintain tactical awareness and used a secondary inertial unit to return to base. The main system was deactivated by the computer itself after detecting an abnormal drift in the GPS coordinates. The return was made without loss of control, demonstrating the value of rigorously tested redundancy.
Managing the human factor in degraded environments
The role of training in degraded mode piloting
The air force tactical simulators include specific modules for flying in degraded mode. These sessions reproduce MFD, CDVE, UHF/VHF radio and even on-board oxygen (OBOGS) failures. The aim is to force the fighter pilot to manage a loss of information without mental disorganization. The air forces require a minimum of two training sessions per quarter in major failure conditions, often in tandem with an instructor.
The Royal Air Force, for example, requires 10 hours per year in “failure intensive simulation” mode, combining successive failures, deteriorating weather and electronic jamming. Feedback shows that pilot performance, even in highly automated systems, remains key as soon as a failure occurs.
The question of the decision threshold: continue or abort?
The fighter pilot must assess the criticality of the failure. An inoperative AESA radar or a faulty IFF does not necessarily justify abandoning a mission. On the other hand, a simultaneous failure of the flight or identification systems may lead to a decision to land immediately or eject. On Rafale, critical data (CDVE, OBOGS, EPU) are classified according to a three-level criticality protocol. Level 1 requires an immediate return. Level 2 allows a short flight to be maintained with a diversion plan. Level 3 allows the mission to be maintained.
In 2017, an Air Force Mirage 2000-5 had to abort a mission after a secondary hydraulic system alert. The decision was made in 45 seconds, following a standardized sequence. The return was made without any additional alarm, but the procedure demonstrated the impact of a rigorous protocol on the overall safety of the flight.
Ejection or recovery: extreme action thresholds
The last protocol is ejection. The ejection seat (e.g. Martin-Baker MK16, zero-zero) can be activated in less than 0.4 seconds. It guarantees ejection even at zero speed and zero altitude. The cost of a complete seat exceeds €320,000 and each survival capsule is equipped for 72 hours of autonomy. The decision to eject is strictly personal, but is based on predefined criteria: irreversible loss of control, cumulative failure of flight controls, internal fire. The air forces estimate that there is one ejection for every 2,800 flight hours on the Rafale and one for every 2,100 hours on the Typhoon.
A functional chain, not infallible
The safety protocols in the event of a failure of the electronic systems of a fighter plane are not simply automatic. They involve a sequence of human actions, software redundancies, continuous monitoring and tactical decisions. The maintenance costs of these systems are high: a complete check of the inertial systems costs an average of €12,000 per aircraft. The robustness of the equipment does not eliminate the risk, but it does reduce the uncertainty factor. In the age of electronic warfare and cyber threats, the ability to maintain functional consistency in flight remains a strategic criterion. The pilot, trained in realistic scenarios, remains the main actor in this risk management.
War Wings Daily is an independant magazine.