Air Force evaluates F-22 braking system during cold-weather tests

Published Nov. 30, 2007
By Airman 1st Class Nora Anton
354th Fighter Wing Public Affairs

EIELSON AIR FORCE BASE, Alaska -- An F-22 Raptor from Edwards AFB, Calif., underwent three weeks of cold weather testing on its braking system here in November. Test results will, in turn, aid the two F-22 fighter squadrons at Elmendorf AFB, Alaska, as winter approaches.

Tests allowed officials to validate the F-22 braking system's stability and performance as well as evaluate cold-weather operations and maintenance procedures.

According to Maj. Jack Fischer, the 411th Flight Test Squadron deployment commander and an F-22 test pilot from Edwards AFB, stopping on problem-surfaces is a challenge for every Air Force jet.

"We were testing the Raptor's behavior while maneuvering and stopping on slippery surfaces," the major said. "Whether during a snow storm or ice fog, we have to be able to land on poor surfaces. The F-22 demonstrated incredible brake-system stability on low-friction surfaces.

"Mother Nature also helped out by giving us the necessary weather conditions during the majority of our test window," Major Fischer said. "Testing is about finding strengths, weaknesses and limits. The team learned plenty.

The aircraft was tested on incrementally low-level runway conditions reading (RCR) surfaces, or how contaminated the runway is and how much concrete you will need to stop the aircraft, in temperatures ranging between 37 to 13 degrees below zero, said Richard Backs, a 411th FLTS project manager.

The team needed the temperature to be cold enough to freeze water in order to create a test surface.

"We started with basic ground maneuvering on an icy surface and progressed to high-speed braking tests and eventually, both real and aborted, take-off and landings under low RCR conditions," Mr. Backs said.

The F-22's anti-skid system is only used in the F-22. No other planes have this kind of system, Major Fischer said.

"It's like an anti-lock brake system in your car, but on steroids," the major said. "In addition to looking at wheel slip (like in your car) this system also accounts for deceleration through its navigation system, and allows the aircraft to safely and reliably stop on any surface that it may encounter."

According to Mr. Backs, they obtained information that will enable them to update the aircraft's flight manuals to enhance the safety of the operators in the field.

The data will also contribute to other important factors.

"We were also able to develop F-22 cold weather pilot and maintenance techniques and procedures, as well as gather enough data to update the takeoff and landing distance charts in the F-22 publications," Major Fischer said.

The F-22 has already undergone extensive hot and cold weather testing at the Air Force McKinley Climatic Lab at Eglin AFB, Fla. Major Fischer said the aircraft was subjected to incredible environmental conditions; however, they could not test the braking system there.