Incident
A pilot reported a partial loss of engine power while on final approach. The aircraft made a forced landing to the right of the runway, resulting in the collapse of the main landing gear.
Examination
Post-incident examination of the engine revealed that the fuel metering unit inlet screen was 75 percent blocked with green, lint-like debris. The debris was removed, after which the engine started normally and ran without interruption.
Maintenance Program
The 1973 Cessna 206F (model U206F) was maintained under the Cessna Progressive Care and Continuous Inspection (CPCCI) program. The CPCCI program was originally designed for 1977 through 1986 airplanes, but Cessna established procedures for vintage airplanes not specifically covered in that program. The CPCCI Operations Manual stated that after reviewing the specific aircraft, inspection requirements for items not covered should be added to the Operation Schedule.
A review of the 1969 through 1976 206 Service Manual revealed that the fuel injector screen should be inspected every 50 hours. The Teledyne Continental Motors (TCM) 100-hour maintenance schedule also required removal and inspection of the fuel metering unit inlet screen for foreign material. However, the 1977 through 1986 206 Service Manual did not include a requirement to inspect the fuel injector screen. Cessna could not explain why this inspection was included in the earlier manual but omitted from the later one.
On April 17, 2002, the operator added the fuel metering unit inlet screen inspection to the CPCCI program under Operation #1 and #3, item J25.