US Air Force tests F-35A refuelling at 5,000ft

The US Air Force has started flight testing that would let its Lockheed Martin F-35A strike fighters refuel in the air at lower altitudes than currently allowed. The Air National Guard Air Force Reserve Command Test Center (AATC) said the floor for the type is 10,000ft.

The F-35A is the only fighter in the air force's inventory that cannot refuel below that height, according to the test centre. On 29 September the AATC said evolving tactics call for taking on fuel at lower altitudes to improve survivability and lethality, and pilots need to train that way before doing it in combat.

During one recent sortie over the Gulf of Mexico, a Boeing KC-135 passed fuel to an F-35A flying as low as 5,000ft. The AATC called the event a first for the fifth-generation stealth fighter. The flight was carried out with the air force's Air Combat Command and the F-35 Joint Program Office, which handles procurement and modernisation for all F-35 operators.

The 5,000ft refuelling is the opening phase of a planned test campaign, the centre said. Further phases will build on the results to widen the F-35A's refuelling envelope and make the capability available to operational pilots. The AATC also said it met the requirement within seven months of receiving it.

Earlier in the year the test centre completed a comparable effort, bringing a new aerial refuelling probe for the Fairchild Republic A-10 attack jet through development and certification in a matter of weeks. The A-10 had been limited to taking fuel from KC-135s because of long-standing engineering problems with the refuelling boom on Boeing's KC-46, which is too stiff to work effectively with the aircraft.