C-135 / Kc-10

Flying Safety,  Jan-Feb, 2002  by Maj Phil Schroeder

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FY01 was another good year in the C-135 and KC-10 community. As of this writing, the trend continues with no loss of life and no destroyed aircraft. Well Done! With Operations ENDURING FREEDOM and NOBLE EAGLE now in full swing, the air refueling business is busier than ever, so keep your heads up. Be smart. Plan accordingly. Let's continue the trend that has been established.

Because of safety privilege, it's often difficult, if not impossible, to discuss details and causes for many mishaps, particularly m a public forum like this. I encourage you to visit your local Flight Safety Office folks and take a look at the mishap messages related to the following accounts, so that you can learn from them and avoid similar events yourselves.

C-135

The C-135 did not experience any Class A Flight Mishaps, although a seven-inch pair of diagonal cutters left in an engine during a ground maintenance run resulted in a Class A Ground Operations Mishap. There were a variety of mishaps in the other classes. The uncommanded horizontal stabilizer trim saga continues for the C-135.

Most of the Class B mishaps involved aircraft engine damage.

* While taxiing for departure, the No. 4 engine stall light illuminated, followed by an EGT rise. The aircrew shut down the engine, restarted it and continued the mission. At the power reduction for level-off, the No. 4 engine started shuddering and fuel flow and RPM rolled back. The engine was placed in idle and the mission terminated. The engine suffered compressor damage.

* On three different sorties, all flown sequentially, the aircraft's No. 2 engine was noted to have higher EGT readings than the other engines, although all EGT readings were in the normal operating range. After the second sortie, maintenance examined the engine and launched the aircraft on the third sortie with the power management control turned off. On takeoff, nearly full throttle was required to reach the reduced takeoff thrust setting. The remainder of the mission was flown as planned. After landing and maintenance inspections, the engine turbine area was found to have Class B damage.

* An aircraft returning from PDM was found to have significant FOD damage in the high pressure turbine section.

* An aircraft's No. 3 engine wouldn't produce the required thrust for takeoff. The aircrew aborted and maintenance performed an engine run that resulted in a compressor stall. Borescope inspections revealed Class B engine damage.

* During a Tornado air refueling using the Multi-Point Refueling System, slack developed in the refueling hose. The reel system didn't take it up in a timely manner and a sine wave developed. The sine wave broke off the receiver's refueling probe and caused Failure of the drogue basket coupling, which fell to the forest below.

* An unattended, unchocked flight-line vehicle, in which the emergency brake was not applied, rolled 500 feet and contacted--what used to be--the No. 1 engine tailcone assembly.

There were assorted Class C mishaps.

* An RC-135 experienced No. 4 engine rollback shortly after takeoff. The engine had to be shut down because of turbine blade failure.

* A KC-135 engine over-temped during takeoff and climbout.

* Landing in crosswinds and scraped engine pods accounted for two Class C mishaps.

* On approach to home station, in clouds, at the freezing level, with precipitation, a lightning strike zapped a KC-135.

* Another aircraft suffered Class C lightning strike damage while attempting to navigate between two heavy rain showers while being vectored for an approach at home station.

* An APU was damaged during preflight when the turbine wheel seized.

* While performing a practice emergency separation during air refueling, the tanker autopilot disconnected, the aircraft pitched up abruptly and stab trim began running rapidly in the nose up direction. The horizontal stabilizer brake wasn't functioning properly.

* During an air refueling mission, the pilot director lights showed "A" for "Aft,' meaning the receiver should move aft. The receiver pilot interpreted the lights as "I'm Aft" and needed to move forward. The boom operator's "Back Four" calls did not register with the receiver pilot. A breakaway was initiated before the separation was complete and the boom ice shield was damaged.

* Another ice shield got damaged when, during a night air refueling mission with reduced visibility and light turbulence, the receiver approached the inner air refueling limit.

* A receiver pilot became erratic within the air refueling envelope and the boom operator initiated a breakaway. However, the receiver hit an aft limit, resulting in a brute force disconnect.

* During an E-3 refueling, headed into the sun, the receiver approached an inner limit. The receiver pilot didn't respond to the boom operator's verbal corrections. The boom operator attempted a disconnect. However, due to forward movement of the receiver, the boom nozzle was unable to be retracted from the receptacle. Prior to disconnect, the receiver contacted the ice shield.