[Kymmy]

Originally Posted by Hom3r

I saw that as well, and I've seen the tech manuals and in some case the tolerances are several thousandsth of an inch.

Airbus (who build the A380) is a part of EADS

Sorry I meant ESA, the third program is about a satellite.

---------- Post added at 09:24 ---------- Previous post was at 09:16 ----------

Originally Posted by Lord Nikon

Would I be corrrect in assuming the drogue and main chute are designed to trigger at an altitude lower than the aircraft's at time of deployment to avoid the possibility of becoming entangled in the fuselage during descent? if so then that would explain it as when you're at a height of 0AGL then there isn't much room for a negative. It would also explain the minimum safe deployment height AGL to allow for full canopy opening.

The drogue should deploy at roughly the apogee of the seats flight... The drogue then pulls the parachute and the pilot free from the seat before descent (the seat has lateral speed as well at this point which is enough to act on the drogue). The seats trajectory is set to allow enough separation of the seat to aircraft so not to allow the pilot to land on top of the plane even at zero speed.

Full timeline for the Mk10 is as follows

- Seat firing handle pulled causing seat initiation cartridge to fire
- Harness retraction unit operated, command firing initiated
- Primary cartridge fired causing inner and intermediate pistons to rise, releasing top latch
- Seat rises up guide rails
- Miniature detonating cord trip initiates canopy fracturing system
- Secondary cartridges fire in turn as seat rises
- Electrical connections separate disconnecting seat actuator circuit, IFF
switch and oxygen regulator supply lead
- Aircraft portion of main oxygen generating system block separate
disconnecting main and back-up oxygen
- Personal equipment connector aircraft portion disconnects from seat portion
- Anti-g suit hose disconnects
- Leg restraint lines draw back and restrain aircrew’s legs
- Leg restraint lines become taut and rivets shear, freeing lines from floor brackets
- Trip rods withdraw sears from drogue gun and barostatic time-release units
- Emergency oxygen trips
- Remote rocket initiator operated by static line, cartridge fires to ignite rocket pack

- Rocket pack sustains upward thrust of ejection gun, diverging trajectories for front and rear seats
- After delay mechanism has operated, drogue gun piston fires
- Ejected piston withdraws closure pin from closure flaps of drogue parachute pack and deploys drogues.
- Deployment of drogues stabilize and retard the seat and aircrew

- Low altitude/High speed -
- Seat descends stabilised by drogues
- Barostatic time-release unit completes run and fire

- High speed/high altitude -
- Barostatic capsule operates to prevent parachute deployment above pre-determined altitude
- Barostatic controlled g-switch delays parachute deployment above 7000 ft until speed and g-force are reduced
- Barostatic time release unit operates below pre-determined altitude, completes run and fires

- Manual separation (override) used if automatic system fails
- Gas from cartridge used to
- Free drogue shackle link
- Release parachute mechanical lock
- Operate upper harness locks and lower harness release mechanism to free lower harness lugs, negative-g straps, leg restraint lines and personal equipment connector man portion
- Drogues withdraw parachute from container
- Sticker straps momentarily hold aircrew in seat
- Parachute develops, lifts aircrew and survival pack from seat and pulls sticker clips from clips causing aircrew and seat to diverge
- Normal parachute descent follows
- Aircrew releases either of two quick-release connectors to lower survival pack to end of line
- Survival pack opened manually when necessary

Again from the unofficial sources the control box that sequences the above events might have failed causing the unintentional firing of the rockets and nothing else.