LANGLEY AFB, Va. — The U.S. Air Force is reviewing its plans for combat search and rescue (CSAR), to determine whether current fleet-sizing assumptions for the HH-60G and replacement Combat Rescue Helicopter (CRH) still reflect operational needs.

The baseline demand for the service has been for 148 rotorcraft, with a recognition that available funding only allows for 112 to be operated. An update of the core function master plan, due for completion in the fall, could alter that figure as the service assesses whether the fleet plan matches strategic assumptions, says Col. Bernie Willi, personnel recovery lead for Air Combat Command at Langley AFB, Va.

Even as the service looks to select a new helicopter through the CRH program, with a planned initial operational capability in 2018, it is also wrestling with how to preserve current capacities.

Three HH-60Gs have reached more than 10,000 flight hours, with eight more around 9,000 hr. Those are mainly employed in the U.S. to preserve lesser-used airframes for overseas missions. One challenge is that the Air Force lacks a service-life estimate for the aircraft.

Furthermore, structural and avionics maintenance problems are on the rise. Since 2008, the maintenance man-hour per flight hour demand on the Pave Hawk fleet has increased 30%, Willi says, in part reflecting the high operational pace. Although the drawdown of military activity in Iraq and Afghanistan has slightly moderated the pace of operations, it has not dropped as fast as some believe, Willi notes.

Structural fatigue is believed to have caused the retractable refueling probe on one HH-60G to break away from the aircraft in flight about a year ago. The root-cause analysis is still under way.

The Air Force’s problems are compounded by the fact that the UH-60L, on which the Pave Hawk is based, is being phased out by the U.S. Army, so the Air Force is struggling to figure out how to preserve its access to spare parts.

The Air Force currently has a fleet of 98 HH-60Gs based on the L-model Black Hawk. The Pentagon also has provided funding for UH-60Ms to be converted into CSAR helicopters to make up the gap — three of those have already been delivered from Sikorsky. But the Air Force is considering trading those in to the Army, because the M-model and L-model are very different and there are currently no design drawings to turn an UH-60M into an HH-60G. The details of that transaction are still being worked out.

Even with the CRH program on the horizon, the HH-60G is still seeing incremental upgrades. For instance, the U.S. Navy has loaned 10 missile warning systems with hostile-fire-indicator capability to the Air Force for use on the HH-60Gs. Those are now operational in Afghanistan.