Amateur/Home Built/Experimental
Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Engineer; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 8; Flight Crew Total 12000; Flight Crew Type 1030
Aircraft Equipment Problem Critical
Aircraft Equipment Problem Dissipated; Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Aircraft; Weather
I flew most of the flight VFR at 11;500 FT; OAT gauge indicated 46 F. Later in the flight I needed to air file and received an IFR clearance due to low ceilings at destination. While descending into very hot and humid conditions; I was instructed to descend from 6;000 MSL to 5;000 MSL. Passing approximately 5;200 MSL I noticed a considerable loss in engine power. I also noticed the #2 EGT had gone to zero on GEM 602 engine monitor. Other EGT's were lower than normal but still indicated something on the engine monitor. [I] could not maintain the assigned 5;000 FT without a significant reduction in airspeed. I attempted to apply carb heat but this seemed to reduce engine RPM even further. I also increase the mixture to a more rich setting but this also reduced engine RPM. Found best power with carb heat off and a very lean mixture. I then notified Approach that I could not maintain altitude and needed to proceed direct to destination. Further noticed that I was passing over an en route airport and advised Approach that I would like to land there. Approach cleared me to proceed as requested and advised me of the runway direction; length and width. I asked if I should switch to the airport's UNICOM frequency or stay with them; they advised that they showed no traffic in the area and to stay with them; and to radio them when safely on the ground. I set up for an engine out approach; but the engine continued to give partial power throughout the landing. I landed and taxied to parking without incident. While parked I preformed a mag check and adjusted the throttle and mixture to restore full static power. After adjusting these controls a few minutes I managed to restore full static engine power. I suspect the root problem was carb icing which melted out within a few minutes of landing. Further suspect the carb heat might have eventually melted the ice while in the air; had I given it more time. I called Approach from the FBO.
Long EZ pilot experiences loss of engine power during descent in humid conditions. Carb heat does not solve the problem and the reporter elects to divert to a suitable airport. The engine continues to run and full power is restored once on the ground. Carb ice is strongly suspected.