​The Boeing KC-46A Pegasus in-flight refueling tanker formally transitioned into Initial Operational Test and Evaluation (IOT&E) on 22 October.

The Boeing KC-46A Pegasus in-flight refueling tanker formally transitioned into Initial Operational Test and Evaluation (IOT&E) on 22 October.

The US Air Force programme executive officer for the tanker formally certified the long-awaited process, the service says in a media release.

IOT&E is intended to test the KC-46A’s effectiveness, suitability and capabilities for its three primary missions: air-to-air refueling, cargo and passenger operations, and medical evacuation, says the USAF.

Boeing KC-46A Pegasus

Boeing KC-46A Pegasus tanker practicing refuelling F-16 fighters


While the USAF starts operational tests of the KC-46A, Boeing will continue to work in parallel on fixes to category-one deficiencies in the aircraft’s design. The service decided to move forward with IOT&E despite the tanker’s lack of full functionality as it thinks in the long run it would be the fastest way to achieve full operational capability, which the USAF hopes will come by 2022 or 2023.

“Air Force leadership remains concerned with Boeing’s slow progress resolving issues limiting the KC-46’s operational capability and continues to work with Boeing to ensure the KC-46 meets all essential mission requirements,” the service says in a statement.

That statement echoes comments made in September by General Maryanne Miller, commander of the USAF Air Mobility Command, on the KC-46A’s remote vision system (RVS) – the camera-based technology that helps crew guide a refuelling boom to receiving aircraft.

In particular, Boeing is having difficulty improving the camera’s resolution. Boom operators see images with degraded 20/50 vision and poor depth perception, says the USAF. The camera also has struggled to adjust to sun glare, which causes the monitor to washout.

The service has labelled the RVS problem a category-one deficiency, meaning a problem which "may cause death or severe injury… or major damage to a weapon system”. Category-one deficiencies can also restrict combat readiness or lead to a production line stoppage, the USAF says.

Boeing is also working to fix another category-one deficiency found by the USAF in September. During a recent mission, the service found that cargo floor restraints became unlocked in flight. Those floor restraints hold pallets in place, preventing cargo from shifting or sliding around during flight, an event which might endanger the aircrew and aircraft.

After discovering the problem, the USAF banned the KC-46A Pegasus from carrying passengers and cargo. Resumption of KC-46A flights with cargo or passengers have not yet been announced by the USAF.

The USAF has said the KC-46A is “a great airplane”, but is frustrated by Boeing’s quality problems. The service is eager to see those problems fixed and wants to procure more KC-46As so it can retire its fleet of aging Boeing KC-135 Stratotankers.

Boeing received a $2.63 billion contract from the USAF for 15 additional KC-46A tankers in September. The company is now on contract for 67 tankers.