A-10 Cracked UARRSI during flight test

The following photos and narrative were provided by Billy Meeks, a former flight test boom operator at Edwards AFB.

It’s been said , “one good test is worth a thousand opinions”. It’s also axiomatic that no test, regardless of outcome, is a failure. It may contain some elements of failure but, if something is learned that can lead to success, then the test is a success even in failure. The accompanying photos are an example. Phil Zamagne was the lead on a night lighting evaluation of A-10 lighting. We went out after dark and caught up with an A-10 being piloted by an AFTEC (previous to AFOTEC) pilot for an operational look. Phil completed his test card deck and concluded the test. I sniveled for one more contact and he permitted me to do so. The A-10 returned to the precontact, reported ready and moved forward. I put the nozzle in the receptacle and instead of a contact made light, all the lights went dim on the instrument panel. I reset with the nozzle in contact and got the same result. So, I thought let’s start over here and retracted the boom except it would not come out of the receptacle. Uh, Oh. So I monkeyed with it and it still would not come out. By now the A-10 guy was starting to get a little antsy and pretty much started running th limits. I/we finally got him settled down and following us and we tried a bunch of stuff all to no avail. I/we are starting to get concerned. After discussing our options we were down to a forced disconnect. So I set it up with him at mid boom and he retards his throttles, slides back to the end and, KLUNK. We are still stuck with him and him with us. Oookaay, let’s try this again. Same thing. All right, let’s enhance this a bit. Started him at 6 feet, he pulls his throttles and I stand on the extension. Zip, KLUNK. So we know we can’t land this way and he’s not amenable to us dragging him off on Mount Whitney. Just what are we going to do. I’m wondering if Phil is laughing at me but I’m scared to look to see. As it turned out the A-10 is one of two prototypes and had hydraulic system control switches. Someone asks and he confirms and turns off the switches and just like FM the boom comes out. This whole thing went on for what seemed like 30 minutes.

What happened? The A-10 has/had a “T” handle which controlled the deploy/retract function of the UARRSI. When he came back he pulled the handle but not all the way out. That allowed the slipway to bleed down but not lock down. He got a ready light as he normally would. When the boom went in it created an air flow situation such that the slipway door floated up behind the ball joint and captured the receptacle. See fotos, zoom and note the fractures in the assembly.

The fix: redesign such that the handle had to be fulled extended and locked by turning 90 degrees. This is a test failure that resulted in a successful outcome.

I’m claiming hero status for Phil and I since we maybe prevented some youngster from from finding out what it was like to land hooked up to an A-10.

 

A-10 Refueling From a KC-97L

Two Fairchild Republic A-10As refuel with a Boeing KC-97L Stratotanker (S/N 53-355) of the Texas Air National Guard. (U.S. Air Force photo) Click image to enlarge.

In this picture a pair of Fairchild A-10As are being refueled by a KC-97L. I am unaware of the exact date of this picture, but the A-10 first flew on 10 May 1972 and the KC-97 was retired in 1978 so the picture must have been taken somewhere in that window.

The Strategic Air Command took delivery of its first KC-97 on 14 July 1951. The main production version of the KC-97 was the KC-97G of which 592 were built. By 1958 SAC operated 780 KC-97s, but the 1957 introduction of the KC-135 meant that the -97s days were numbered. The piston powered KC-97 was too slow for the new generation of fighters and too small for the newly introduced B-52.  The KC-135 was an all new design that was more than fast enough to keep up with the fighters and had sufficient offload to support the B-52. In 1958 SAC began to decommission its KC-97 fleet.

In April of 1961 the Air National Guard received its first KC-97 from SAC. The mission of the KC-97 under the guard was to refuel the Tactical Air Command’s fighters. During refueling with fighters the KC-97 was required to fly as fast as possible while its receiver flew on the edge of a stall. Often times the refueling had to be conducted in a shallow dive (toboggan) so that the tanker could maintain a minimum speed required by the fighter. Surplus General Electric J47 jet engines were available from decommissioned KB-50 tankers and they were added under the wings of the KC-97E/Fs. The upgraded aircraft was redesigned the KC-97L. Each J47 produced 5,800 lbs of thrust which drastically increased the performance of the KC-97 and gave it enough extra speed to keep up with fighters of the day.

Just as the KC-97 was too slow for fighters of the day, the KC-135 was too fast for the A-10. Refueling between a heavily laden A-10 and KC-135 produced a situation where the A-10 did not have enough thrust to fly at the KC-135’s minimum flying speed. When refueling A-10s, the KC-135 was limited to a maximum gross weight of 250,000 lbs and even then it was often required to lower its flaps to 20º or 30º. The KC-97L and A-10 were a perfect match due to their similar flying speeds.

Sources:

• http://books.google.com/books?id=C04zANFFmzgC&pg=PA58&dq=kc-97l&as_brr=3&ei=OBoHSo6zI4vKNdv-tYUC#PPA56,M1
• KC-97 Stratotanker. (2009, April 19). In Wikipedia, The Free Encyclopedia. Retrieved 19:12, May 10, 2009, from http://en.wikipedia.org/w/index.php?title=KC-97_Stratotanker&oldid=284815953

Image Source:

• http://www.nationalmuseum.af.mil/shared/media/photodb/photos/051128-F-1234P-025.jpg