Adding Stopping Power For A USAF Workhorse

Members of the 418th Flight Test Squadron C-130 Hercules Wheel Brake System Improvement program at Edwards AFB are testing the performance of carbon brakes and the new Mark IV Digital Antiskid Control Unit for the aircraft to replace the C-130's legacy brake system. Members of this test group said they know the lives of current and future C-130 crewmembers depend on them doing their job right.

"My primary objective is to make sure the carbon brakes and the Mark IV are equivalent to or better than the legacy steel brakes and the Mark II Analog Antiskid system," said Colin Young, a 418th FLTS subsystems engineer. "If the tests are successful, then the brakes will be retrofitted to all C-130s, other than the C-130J (that already uses the new brakes)."

Parts for the current legacy brake system are becoming scarce because they are no longer being manufactured, so the need for new brakes is significant. The testing involves max-effort braking where the pilot would apply the maximum pressure to the brakes to stop the cargo plane. Different test points include observing how the carbon brakes perform with different cargo weights and wet-runway tests to evaluate the digital antiskid system.

Mr. Young said the carbon brakes are designed to have a 25-percent increase in thermal capacity when compared to the current steel brakes, which reduces potential for brake fires and locking up. The brakes also reduce stopping distance.

For testing purposes, team members drilled holes into the center stator and inserted thermal probes into the brakes to obtain real-time brake temperatures during testing. Test officials said temperatures are essential to determine how hot the brakes get during maximum effort braking and to evaluate the cooling profile of the brakes.

"The one thing you find with steel brakes is they cannot handle as much heat, and they certainly heat up a lot quicker than carbon brakes," said 1st. Lt. Nicole Potter, a 418th FLTS flight test engineer. "The nice thing about steel brakes is they dissipate the heat quickly, and we're finding with the carbon brakes it takes a little longer to cool, but their capacity to handle heat is a lot better."

Along with better performance, the new carbon brakes are more durable and efficient.

"From a logistics point of view, the old brakes can last up to 4,000 miles of landing distance," Mr. Young said. "The new brakes can last 25,000 (miles), so it's almost six times better in terms of logistics support." With C-130s doing constant missions throughout Southwest Asia, a new braking system stands to benefit cargo pilots down range and that fact is not lost on the test team.

"The warfighters have had a continuous problem with the wear-out of the brakes and the turnaround time to rebuild them," said Lance Stoebling, assistant program manager.

"Composite brake systems are coming out throughout the Air Force and the C-130 is next on the list." A C-130E on loan from the 19th Airlift Wing at Little Rock Air Force Base, Ark. is being used to accomplish testing and is scheduled to complete one last mission for the Air Force before it is decommissioned. WBSI testing is scheduled to conclude in July.

Since testing began in March, Mr. Stoebling said the 418th FLTS has completed 100 percent of the legacy baseline brake testing and about 75 percent of the new brake system tests.

"So far, it looks very promising," said Mr. Stoebling. [ANN Salutes Kenji Thuloweit, 95th Air Base Wing Public Affairs]

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