M-7
Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 120; Flight Crew Total 630; Flight Crew Type 5
Confusion; Situational Awareness; Training / Qualification; Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; Flight Crew Diverted
Human Factors; Weather; Aircraft
I was flying a Maule into IMC and light rain while being vectored around thunderstorms at 4;000 MSL. As I began flying through the clouds I turned on the carb heat in order to keep ice from forming in the carburetor. As soon as the rain began; the engine ran a little rough and progressively began choking. At full throttle it was only putting out 1;500 RPM. This was not sufficient thrust to maintain altitude. Throughout this incident I lost 500 FT from my on course altitude. The Controller mentioned that my altitude was indicating lower than 4;000 FT. I told the Controller I was unable to maintain altitude and that I wanted vectors to the nearest airport. The Controller did a fantastic job redirecting me to the nearest airport and I was able to land the aircraft without incident.
An M-7 pilot flying IFR in rain was unable to maintain power and requested ATC vectors to a nearby airport where a safe landing was accomplished.