Escape crew capsule

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Crew escape module for the F-111A

A escape crew capsule allows a pilot (or astronaut) to eject from his or her craft and still be protected at extreme speeds and altitudes which might not be survivable in a simple ejection seat.

There are two ways to do this:

ejecting individual crew capsules (one for each pilot/crew member) or "capsule ejection", and
ejecting the entire crew cabin, or "cabin ejection".

Some examples of U.S. Military aircraft that have escape crew capsules comprise:^[1]

The B-58 Hustler and XB-70 Valkyrie had individual encapsulated seats, a cabin ejection for the XB-70 Valkyrie however was tested.
The F-111 used cabin ejection where both side-by-side seats were in a single 3000-lb capsule.^[2]
Three of the four B-1A prototypes also used cabin ejection. They had a single capsule "roughly the size of a mini-van" ^[3] for all four crew members.

The first escape capsule designed was for the U.S. Navy F4D Skyray.:^[4] It was tested in 1951-52 but was never installed in the aircraft. The Bell X-2, designed for flight in excess of Mach 3, could jettison the cockpit, though the pilot would still have to jump out and descend under his own parachute.^[5] The first production aircraft with an escape crew capsule was the Mach 2 B-58 bomber. The capsule was pressurized, sheltered the pilot from the airstream, and contained food and survival supplies. ^[6] ^[7]

The Mach 3 XB-70's two crew escape capsules did not work well the only time they were needed. On June 8 1966, XB-70 airframe AV/2 was involved in a mid-air crash with an F-104 Starfighter. Maj. Carl Cross's seat was unable to retract backwards into the escape capsule due to high-g-forces as the plane spiraled downwards. He died in the crash. Maj. Al White's seat did retract but his elbow stuck out too far and blocked the closing clamshell doors of the capsule. He struggled to free the painful elbow. As soon as it was in and the doors closed, he ejected the capsule which exited the plane and descended by parachute as planned. However, due to pain and confusion, White failed to trigger the manually-activated airbag which would normally cushion the capsule upon landing. When the capsule hit the ground, White was subjected to an estimated 33 to 44 g's. He received serious injuries but did survive. ^[8] ^[9] ^[10]

In the 1960s and 1970s, the F-111 and B-1A introduced the idea of the entire section of the front fuselage for crew escape. The crew would remain strapped in the cabin, unencumbered by a parachute harness. 27,000 lbs of thrust from rockets push the module out into the air, and multiple large parachutes are used to bring the capsule down, in a manner very similar to the Launch Escape System of the Apollo spacecraft. On landing, an airbag system is used to cushion the landing, and this also acts as a flotation device if the capsule lands in water. The capsule is also usable as a shelter on land. Only the F-111 would retain this feature in service. When it worked, it worked very well.

Three of the four B-1A prototypes featured a single crew escape capsule for the crew members. For the fourth prototype and for the B-1B, this was changed to use conventional ejection seats. One cite gives the reason "due to concerns about servicing the pyrotechnical components of the system,"^[11] another cite says this was done "to save cost and weight."^[12] On August 29 1984, B-1A prototype #2 crashed and the capsule was ejected at low altitude. The parachute improperly deployed and one of the three crewmembers aboard died. ^[13] ^[14]

An escape crew capsule was also incorporated into some of Gerry Anderson's complex vehicles on the Thunderbirds (TV series).

For more information on the advantages and disadvantages of B-58/XB-70 style capsule ejection vs. F-111/B-1 style cabin ejection, see Space Shuttle abort modes.