JAS 39 Gripen - an overview: The escape system

The escape system consists of a Martin-Baker 10LS seat, affording safe ejections

• up to speeds of 1150 km/h at low altitude and Mach 1.8 at high altitude
• up to an altitude of 16 km
• at zero altitude and zero speed
• down to an altitude of 100 m during inverted flight
• down to an altitude of 700 m during a vertical dive
• during G loads between +6G and -3G

The canopy is fractured by a miniature detonation cord running around the frame and down the centre line.

The seat gun has one primary and two secondary charges which goes off in sequence, so the G force is 18-20 G during ejection. This phase lasts 0.19 s. When the seat reaches the edge of the canopy the rocket motor which burns for 0.25 s starts.

To avoid the fin, the trajectory is angled to the left.

At zero altitude and speed the pilot reaches an altitude of 70 m. For altitudes under 3000 m the sequence from pulling the handle until the pilot is under the chute takes 2 s.

Two-seater

The two-seat version has an airbag which inflates for a brief moment in front of the rear crew member to protect against canopy fragments. It's deflated before ejection.

The front seat's trajectory passes the fin on the left side, the rear seat passes it on the right side, this to ensure larger separation between the pilots.

Steerable chute

The chute in batch one aircraft has a drift speed of 3 m/s, which doesn't change with steering (it's the first Swedish air force steerable rescue chute). From batch 2 a chute with a drift speed of 0.5 m/s when it's not steered and 3 m/s when steered is introduced. Apart from giving the pilot a better possibility to choose landing spot, the slower drift speed is safer for an incapacited pilot.

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