Reporter-News Archives

Friday, February 20, 1998

Ejection system that saved B-1B crew is top-notch

By BETH HALLMARK / Abilene Reporter-News

The ejection system that catapulted four crew members of a crashing Dyess Air Force Base B-1B to safety on Wednesday is one of the best, one of its maintainers said on Thursday.

"This particular system in the B-1 has one of the highest survival rates for initiated ejections of any of the ACES equipped aircraft out there," said Master Sgt. Thornton McGill with Dyess' 7th Component Repair Squadron.

The B-1 is outfitted with an ACES II (Advanced Concept Ejection Seat) system common in the Air Force's bombers and fighters.

Called the Egress System after the Latin word for "exit," the ejection process involves much more than just the main rocket catapult that propels the crews' seats out of the plane, McGill said.

The rapid-fire sequence of events actually includes about 700 explosions, he said. Once the ejector handle is pulled, one charge blows the bolts off the hatches over the front part of the cockpit. The hatch over the back part of the cockpit, where the weapons systems officers sit, is automatically unlatched.

Pistons propelled by another set of explosives then push the hatches off the plane.

In addition to the main rockets under the crews' seats that sends them out of the aircraft, two other rockets play a part in ensuring the crews' safety, McGill said.

One stabilizes each seat so it flies straight, while the other generates a small burst to direct the crew in different directions.

"It's very minimal, but the change in direction is more than enough," McGill said.

In the B-1B, the pilot and co-pilot sit about 2 1/2 feet from each other. The other two seats, also 2 1/2 feet apart, are located about 10 feet behind the pilots, McGill said.

Once ejected, crew members are sent through the air with a force of about 10 to 15 times the pull of gravity. That means a person weighing 200 pounds would feel as if he weighed between 2,000 to 3,000 pounds, McGill said.

The distance traveled varies widely, depending on the speed of the plane at the time crew members bailed out. McGill said the average distance is 50-60 feet up and away from the plane.

A computer system on board calculates speed and altitude variables to ensure the crew is launched with appropriate force, McGill said.

After exiting the plane, crew members have little to do but wait to land. A mortar built into the ejection seats automatically fires their parachutes. The seat then drops away, leaving each airmen with a survival kit that includes signaling devices, a radio and water.

But the most amazing element of the entire process is its timing. From the time the ejection cord is pulled to the time the last man exits the plane is 3.2 seconds, McGill said.

"That's four hatches, four people ejected with the fourth guy up and out of the plane," McGill said. "If you blinked, you'd probably miss it."

Each crew member can eject individually, or the pilot can eject all four crew members at once.

McGill said careful efforts are made to ensure the safety of the escape devices, but it's the only system on the plane that cannot be tested on the ground.

Though crews continually inspect the systems, McGill said the true tests come in situations like the one in Kentucky on Wednesday.

"We're really glad it did its job," he said.