Maintenance matters

Flying Safety, August, 2004

In this edition we concentrate on the aircraft I started my career on--the BUFF! Here are a few issues the B-52 maintainers have had to face on the flightline.

Ladder Attacks BUFF!

A crew chief was tasked to assist with the removal and installation of the aircraft's No. 5 wheel and tire assembly. While accomplishing aircraft jacking preparation procedures for the wheel and tire removal/installation, the crew chief attempted to move a metal step ladder, which was lying on the ground underneath the No. 4 engine pod. As he lifted the ladder, the ladder swung upward striking the leading edge of the aircraft's No. 8 engine nose cowling and creating a dent at the seven o'clock position. Being a smart crew chief, he visually evaluated the dent and made an initial determination that the dent was within limits, so he did not notify anyone of the incident and proceeded with the tire change. During the aircraft panel inspection prior to flight, the panel inspector noticed the dent in the engine cowling and requested structural maintenance to accomplish an evaluation of the dent. Structural maintenance then determined the dent was out of tech order limits and was not reparable at home station.

What should have happened here? One, watch where the ladder goes. Ground equipment damages a lot of aircraft every year. Two, he should have reported the damage immediately for evaluation instead of letting someone else do his work. If something happens, report it; don't wait. It only gets worse when the reporting is delayed.

Loose Banana

The mishap sortie was briefed as a two-ship formation training sortie to include air traffic control assigned airspace activity, air refueling and transition. During taxi, a required crosswind crab check was performed and the mishap crew (MC) noticed the main landing gear (MLG) was slow to center. The centering of the MLG, however, was determined satisfactory to the aircrew. Takeoff through level-off was uneventful. The aircrew experienced no problems with the aircraft until return to base for the transition leg. Following the first touch-and-go landing, neither left MLG would retract. The aircrew rotated the crosswind crab knob approximately five degrees in both directions and was able to get the left forward MLG to retract. This is a commonly used remedy when any MLG fails to retract normally. The left aft MLG remained extended. The aircrew chose to extend all MLG, leave the gear extended and continue with transition, and experienced no problems with the aircraft during the second touch-and-go.

During the full-stop landing and rollout, the aircrew immediately noticed the MA would not track straight. The crew attempted to manually center the crosswind crab but was unsuccessful. An attempt to center the crosswind crab electrically was made, and the indicator showed centered. The aircraft then began to moderately vibrate. As the aircraft cleared the runway it became apparent there was a problem with the MLG. As the aircraft turned off the runway, the vibration increased significantly, and the crew decided to stop the MA on the hammerhead/taxiway. The MC shut down all engines and requested unit maintenance personnel respond to inspect the MLG. Once at the aircraft, the crew chiefs discovered the No. 3 MLG was turned inward approximately 20 degrees. Further inspection of the No. 3 MLG revealed the No. 3 MLG curved steering metering valve link (banana link) was disconnected from the steering valve arm assembly. The bolt that attaches the banana link to the steering valve arm assembly was found inserted in the steering metering valve arm assembly with the nut attached to the bolt. There were no other components found damaged, loose or disconnected. The banana link was reconnected to the steering valve arm assembly and the aircraft was towed to the designated parking location.

Maintenance technicians performed a visual inspection of the trunnions and structural members in the immediate areas of the aft MLG and found no damage. The No. 3 and 4 MLG strut assemblies, wheels and tires were removed and replaced, and the aircraft has flown several sorties since the incident with no problems associated with the No. 3 or 4 MLG. Why did an aircraft take off without a critical link attached?

Two workers were tasked to cannibalize (CANN) the No. 3 MLG outboard steering actuator rod end pin for another wing aircraft. The workers removed the steering actuator rod end pin IAW tech orders. There is no specific task for removal of an outboard steering actuator rod end pin. To accomplish the steering actuator rod end pin removal, technicians remove, disconnect and loosen certain MLG steering actuator components to facilitate the steering actuator rod end pin removal. The technicians indicated they did not remember disconnecting the No. 3 MLG banana link to facilitate the removal of the outboard steering actuator rod end pin. 781 series forms documentation showed the No. 3 MLG steering plates were disconnected/temporarily installed, the positioning control unit cover removed, the back lash spring disconnected, a temporary outboard steering actuator rod end pin installed and the outboard steering actuator rod end pin canned. There was no forms documentation indicating the disconnection of the banana link.