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Pilot of C177 fails to detect he left the magneto switch in the 'left' vice 'both' position during engine run-up. Significantly reduced performance resulted until he discovered the problem.
| Attributes | |
| ACN | 619902 |
| Time | |
| Date | 200406 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : gpt.airport |
| State Reference | MS |
| Altitude | msl bound lower : 12 msl bound upper : 4000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : gpt.tower |
| Operator | general aviation : personal |
| Make Model Name | Cardinal 177/177RG |
| Operating Under FAR Part | Part 91 |
| Flight Phase | climbout : initial climbout : takeoff cruise : level ground : takeoff roll ground : preflight ground : holding |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument pilot : cfi pilot : commercial pilot : multi engine |
| Experience | flight time last 90 days : 15 flight time total : 2500 flight time type : 300 |
| ASRS Report | 619902 |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : published procedure |
| Independent Detector | aircraft equipment other aircraft equipment : tachometer other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
In 40 yrs of flying, I'd not learned that enhanced performance (excessive RPM drop) of carburetor heat at run-up, may indicate that only 1 magneto is operating. Following magneto check, application of carburetor heat produced a notably greater than normal RPM drop -- about 50 RPM as opposed to the 25 RPM normally experienced in this aircraft. Upon takeoff, acceleration was reduced, climb was significantly reduced, and cruise was about 15 mph slow -- though all engine instruments were good. After cruise was established I noticed the engine was operating on only the left magneto. Switching to 'both' regained normal performance. The lesson learned: enhanced performance of carburetor heat at the ground check may indicate operation on only 1 magneto. Rechk the magnetos.
Original NASA ASRS Text
Title: PLT OF C177 FAILS TO DETECT HE LEFT THE MAGNETO SWITCH IN THE 'L' VICE 'BOTH' POS DURING ENG RUN-UP. SIGNIFICANTLY REDUCED PERFORMANCE RESULTED UNTIL HE DISCOVERED THE PROB.
Narrative: IN 40 YRS OF FLYING, I'D NOT LEARNED THAT ENHANCED PERFORMANCE (EXCESSIVE RPM DROP) OF CARB HEAT AT RUN-UP, MAY INDICATE THAT ONLY 1 MAGNETO IS OPERATING. FOLLOWING MAGNETO CHK, APPLICATION OF CARB HEAT PRODUCED A NOTABLY GREATER THAN NORMAL RPM DROP -- ABOUT 50 RPM AS OPPOSED TO THE 25 RPM NORMALLY EXPERIENCED IN THIS ACFT. UPON TKOF, ACCELERATION WAS REDUCED, CLB WAS SIGNIFICANTLY REDUCED, AND CRUISE WAS ABOUT 15 MPH SLOW -- THOUGH ALL ENG INSTS WERE GOOD. AFTER CRUISE WAS ESTABLISHED I NOTICED THE ENG WAS OPERATING ON ONLY THE L MAGNETO. SWITCHING TO 'BOTH' REGAINED NORMAL PERFORMANCE. THE LESSON LEARNED: ENHANCED PERFORMANCE OF CARB HEAT AT THE GND CHK MAY INDICATE OP ON ONLY 1 MAGNETO. RECHK THE MAGNETOS.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.