4 hours ago
Many years ago I was hired to provide flight instruction in an Exec 90 at the Torrance, CA airport. This is the same airport where the Robinson factory is located. As you can imagine, this is a very busy airport with lots of R22 and R44 test flights being conducted on new aircraft prior to delivery.
The new owner of this Exec 90 owned a jet charter service and was an accomplished pilot. He purchased the Exec 90 to see if he had the aptitude to learn to fly helicopters before investing in a certified ship. He was the third owner and the logbooks indicated that only scheduled maintenance had been performed on this helicopter with no damage history indicated. I did notice that the tail rotor blades looked like they had been recently painted due to the lack of paint chipping on the leading edges. This should have raised some concern but at that time it did not register as anything to investigate..big mistake on my part.
We were able to find a hover area away from all of the Robinson traffic and conducted his hover training which he picked up on quickly. After several days of hover training, it was time to take the helicopter to altitude but the traffic pattern was very congested for initial flight training so we elected to fly out to the coast and then fly south to Long Beach where there was less congestion. The flight out to the coast was over very heavily congested residential and commercial development so once we reached the coast and open beaches I relaxed a little.
The first day we flew down the coast to Long Beach and practiced traffic patterns over the Long Beach container port where there was a lot of open space in case we needed to land in an emergency. We made several trips down to Long beach that day with returns to Torrance to refuel.
The next day we planned to repeat our route for more altitude training so we again flew over all of the developed congestion between Torrance and the coast then turned left to follow the coast line south. We could see a large fog bank about a mile off the shore line and saw a few wisps of fog drifting toward the beach area. We decided that if the fog came in (it was not predicted to come in) we could be stuck in Long Beach and not able to return to Torrance so we executed a 180 degree turn and returned to his home airport.
We made our radio calls and made our approach to the taxiway and set down at Torrance. As we rolled the throttle back to idle to talk, I heard a distinctive tic.tick.tic from the tail rotor area of the helicopter. I told my student to shut the engine down as I got out to investigate the origin of the ticking noise. As I was standing next to the winding down tail rotor it suddenly wobbled dramatically and the entire tail rotor assembly from the pulley outward fell off and was just hanging by the anti-torque cable.
Had that happened anywhere else in our flight we would have been in real trouble, God had protected us to have it happen once we were safe on the ground. In the hangar we pulled the remaining portion of the tail rotor shaft out and found that someone had previously drilled a second set of holes in the tail rotor shaft for the tail rotor pulley bolt. The tail rotor shaft now had four holes instead of the two for the pulley bolt.
The two bolt holes that were not being used by the bolt were oblong from an obvious sudden stop like a tail rotor strike. A crack had propagated unseen under the pulley and traveled the weakest route, from hole to hole until the shaft just broke free. Finding this we called the Rotorway factory and inquired about any tail rotor parts sold to the previous owner. They confirmed that they had recently shipped a new set of tail rotor blades and pitch pins to the previous owner due to a ground strike which destroyed both tail rotor blades and bent the pitch pins on both blades.
The previous owner had replaced the blades and pitch pins, had seen the oblong holes in the shaft for pulley mount bolt, and had elected to just drill new holes and not use the oblong holes. The tail rotor strike was severe enough to bend the pitch pins and that force was severe enough to deform the pulley bolt holes so obviously the tail rotor shaft should also have been replaced, but it was not.
The previous owner made no entry in the log book regarding replacing the tail rotor blades and pitch pins so we did not have any warning to look further until the shaft failed on us. I feel so blessed that this happened when sitting on the ground. Had the fog not caused us to make the decision to turn around and return to Torrance, it could have been a very different story to tell if I was still alive to tell it.
The new owner of this Exec 90 owned a jet charter service and was an accomplished pilot. He purchased the Exec 90 to see if he had the aptitude to learn to fly helicopters before investing in a certified ship. He was the third owner and the logbooks indicated that only scheduled maintenance had been performed on this helicopter with no damage history indicated. I did notice that the tail rotor blades looked like they had been recently painted due to the lack of paint chipping on the leading edges. This should have raised some concern but at that time it did not register as anything to investigate..big mistake on my part.
We were able to find a hover area away from all of the Robinson traffic and conducted his hover training which he picked up on quickly. After several days of hover training, it was time to take the helicopter to altitude but the traffic pattern was very congested for initial flight training so we elected to fly out to the coast and then fly south to Long Beach where there was less congestion. The flight out to the coast was over very heavily congested residential and commercial development so once we reached the coast and open beaches I relaxed a little.
The first day we flew down the coast to Long Beach and practiced traffic patterns over the Long Beach container port where there was a lot of open space in case we needed to land in an emergency. We made several trips down to Long beach that day with returns to Torrance to refuel.
The next day we planned to repeat our route for more altitude training so we again flew over all of the developed congestion between Torrance and the coast then turned left to follow the coast line south. We could see a large fog bank about a mile off the shore line and saw a few wisps of fog drifting toward the beach area. We decided that if the fog came in (it was not predicted to come in) we could be stuck in Long Beach and not able to return to Torrance so we executed a 180 degree turn and returned to his home airport.
We made our radio calls and made our approach to the taxiway and set down at Torrance. As we rolled the throttle back to idle to talk, I heard a distinctive tic.tick.tic from the tail rotor area of the helicopter. I told my student to shut the engine down as I got out to investigate the origin of the ticking noise. As I was standing next to the winding down tail rotor it suddenly wobbled dramatically and the entire tail rotor assembly from the pulley outward fell off and was just hanging by the anti-torque cable.
Had that happened anywhere else in our flight we would have been in real trouble, God had protected us to have it happen once we were safe on the ground. In the hangar we pulled the remaining portion of the tail rotor shaft out and found that someone had previously drilled a second set of holes in the tail rotor shaft for the tail rotor pulley bolt. The tail rotor shaft now had four holes instead of the two for the pulley bolt.
The two bolt holes that were not being used by the bolt were oblong from an obvious sudden stop like a tail rotor strike. A crack had propagated unseen under the pulley and traveled the weakest route, from hole to hole until the shaft just broke free. Finding this we called the Rotorway factory and inquired about any tail rotor parts sold to the previous owner. They confirmed that they had recently shipped a new set of tail rotor blades and pitch pins to the previous owner due to a ground strike which destroyed both tail rotor blades and bent the pitch pins on both blades.
The previous owner had replaced the blades and pitch pins, had seen the oblong holes in the shaft for pulley mount bolt, and had elected to just drill new holes and not use the oblong holes. The tail rotor strike was severe enough to bend the pitch pins and that force was severe enough to deform the pulley bolt holes so obviously the tail rotor shaft should also have been replaced, but it was not.
The previous owner made no entry in the log book regarding replacing the tail rotor blades and pitch pins so we did not have any warning to look further until the shaft failed on us. I feel so blessed that this happened when sitting on the ground. Had the fog not caused us to make the decision to turn around and return to Torrance, it could have been a very different story to tell if I was still alive to tell it.