F-22A #91-4006 with the 411th FLTS lands at Eielson AFB,
Alaska during cold-weather testing 11/5/07
Photo: USAF / Kevin Roberston
11/30/2007 - EIELSON AIR FORCE BASE, Alaska -- An F-22 Raptor
came here for three weeks in November to test the aircraft's
braking system on ice in time for the first snow at Elmendorf
Air Force Base, Alaska, home to several F-22s since August.
"We were validating the F-22 braking system's stability
and performance as well as evaluating cold-weather operations
and maintenance procedures," said Maj. Jack Fischer, the
411th Flight Test Squadron deployment commander and an F-22
"We were testing the Raptor's behavior while maneuvering
and stopping on slippery surfaces," he said. "Whether
during a snow storm or ice fog, we have to be able to land on
poor surfaces. Stopping on problem-surfaces is a challenge for
every Air Force jet."
The F-22, from Edwards AFB, Calif., has already undergone extensive
hot and cold weather testing at the Air Force McKinley Climatic
Lab at Eglin AFB, Fla. The major said the aircraft was subjected
to incredible environmental conditions; however, they could
not test the braking system there.
The aircraft was tested on incrementally low-level runway condition
reading 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,"
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," he 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."
The F-22 came up for a three-week deployment; however, the
team was able to finish all mandatory test points within the
first five days. They were able to use the rest of their time
to fine tune and to collect as much data as possible.
"The F-22 demonstrated incredible brake-system stability
on low-friction surfaces," the major said. "Mother
Nature also helped out by giving us the necessary weather conditions
during the majority of our test window. Testing is about finding
strengths, weaknesses and limits. The team learned plenty.
"We obtained information that will enable us to update
the aircraft's flight manuals to enhance the safety of the operators
in the field," Mr. Backs said.
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.
Source: USAF Press Release by Airman 1st Class Nora Anton