There have been past instances of landing gear actuator rod ends breaking. The following information was sent to me by a Beech contact.Note that while the info is about a Duchess, there are SDRs for the same occurance on Sierras. Actuator rod ends have also failed at the flush lube fitting. Most contacts recommend replacing the rod ends with units that omit the grease fitting, and just oiling it instead. When inspecting the rod ends, make sure that they are not loose on the actuator.
FROM BEECH TECH SUPPORT
Good morning Mike, I know you get involved with the Duchess so here is some info. The other day I received a phone call concerning an incident that occurred to a Beech model 76, S/N ME-8.
It seems that the pilot was letting down for landing when the aircraft shook, and he heard some noise (kind of a rumble-bang noise). He looked around and could not see anything wrong, until he looked at the gear indicators. He had 2 green lights on the main, but the nose gear was not green. Thing is, he had not selected gear-down yet.
He cycled the gear a couple times, but the main gear lights stayed green; the nose gear light indicated correctly. He landed without further incident.
ED. NOTE! If you have heard an unusual noise, and have some green lights, it is very unwise to cycle the gear! It is almost certain that a mechanical failure has occurred. Cycling the gear runs the risk of additional (and very costly) breakage! Just execute the emergency extension procedure. If you get three-green, leave well enough alone and land!
What they found was both main gear actuators rod ends had separated, allowing main gear to free fall to the down position. Over the years doing this job, I have received additional phone calls on the Duchess main gear actuator rod ends. Some have had to land with one gear in the up position, others landed with out incident.
What I am driving at is, it may be a good idea when you talk to Duchess Drivers, to mention these rod ends and to look them over.