SR20
Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 24; Flight Crew Total 3269; Flight Crew Type 1250
Confusion
Aircraft Equipment Problem Critical; Inflight Event / Encounter Other / Unknown
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft; Human Factors
I was flying in a Cirrus SR20 aircraft with the Chief Flight Instructor as part of a Biennial Flight Review. My previous Biennial Flight Review was in June 2012. I had taken off from Runway-XXL at ZZZ before noon and flown to the ZZZ east practice area where I had demonstrated steep turns; slow flight; power-off and power-on stalls; and engine-out procedures. Our intent was then to return to ZZZ and remain in the traffic pattern in order for me to demonstrate landings of various types. We were approaching the airport from the east and had been cleared by ZZZ ATCT to land on Runway-XXL. While turning from base to final at approximately 600 FT MSL; I noticed that the tachometer was indicating higher than I would have expected based on the throttle position that I had selected. I found that further reducing the throttle setting (by pulling the throttle aft) had no effect on the RPM. I chose to go around to diagnose the problem; but on pushing the throttle 'full' forward; I found that the tachometer indication remained unchanged and the aircraft did not climb. At this point we were close to the approach end of Runway-XXL at approximately 400 feet MSL. I advised the Chief Flight Instructor of the situation. She requested that she take control of the aircraft; which I relinquished to her. Given the uncertain state of the engine; she elected to land on Runway-XY and made a slipping right turn to line up with and descend to that runway. Her attempts to regulate the power with throttle were unsuccessful; so at approximately 100 feet MSL I pulled the mixture aft; which reduced the power to idle or lower. The aircraft touched down on the unpaved area near the west end of Runway-XY. Flight Instructor steered the aircraft to the north of the runway; thereby avoiding the threshold lights at the west end of Runway-XY and the approach lighting system for Runway-X further to the west. The aircraft came to rest approximately 950 feet west of the approach end of Runway-X. Aircraft electrical power was then turned off and the fuel selector turned to the 'Off' position; and we exited the aircraft without further incident. The only visible effect of the rollout through the unpaved area was that the starboard main wheel pant and starboard main landing gear fairing were displaced slightly from their normal positions on the landing gear leg. There were no fuel or oil leaks from the aircraft. Upon opening the Oil Access Door; we saw that the rod that extends from the throttle lever was not connected to the throttle on the engine. There was no sign of either: 1) the nut that had secured the rod and throttle or; 2) the cotter pin intended to secure the nut. The most recent Annual Inspection for the aircraft was completed and signed-off eight days prior [to my Flight Review] by Technician X of YY Aircraft Maintenance at ZZZ. Two days later; after completion of the Annual; I had contacted Technician X's Supervisor at YY Aircraft Maintenance to confirm that the Pitot-Static and Transponder Checks had been completed. He ensured me that they had been.
Reporter stated they were sufficiently close to Runway XXL that they would have had to deploy the aircraft's parachute to land on that runway. There was also a berm at the far end that ended at water's edge. He really believes the decision by the Chief Flight Instructor to land on the unpaved area of Runway-XY was a good choice. The surface area was dry; clear and compacted. Reporter stated their Cirrus SR-20 has a Teledyne-Continental IO-360-ES fuel injected flat six piston engine. The twelve year old engine is the original factory installation and has never been changed. Maintenance found the castellated nut that normally secures the throttle lever rod end to the engine throttle body inside the engine cowling. The missing cotter pin was never found. The last recent Annual Inspection did not require disconnection of the throttle linkage. So no determination could be reached as to the cause for throttle linkage separation; other than the possibility of undocumented maintenance; or the cotter pin failing and falling out; allowing the nut to back off from the bolt threads.
During a Biennial Flight Review with a Chief Flight Instructor; a pilot realizes their Cirrus SR20 aircraft engine was unresponsive to any throttle settings. Flight Instructor took control and performed an off-runway landing. Maintenance noted the rod from the throttle lever was not connected to the engine throttle body.