 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Pilot of a beech baron, BE58, descended from assigned altitude due to both engines 'surging' and losing power. Reporter failed to advise ATC at once due to frequency congestion.
| Attributes | |
| ACN | 377580 |
| Time | |
| Date | 199708 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : m39 |
| State Reference | AR |
| Altitude | msl bound lower : 9500 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | Marginal |
| Light | Daylight |
| Aircraft 1 | |
| Operator | general aviation : corporate |
| Make Model Name | Baron 58/58TC |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise other descent other |
| Route In Use | enroute airway : zme |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | other other : other pilot : atp pilot : instrument pilot : commercial |
| Experience | flight time last 90 days : 200 flight time total : 1990 flight time type : 70 |
| ASRS Report | 375580 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | aircraft : equipment problem dissipated controller : issued new clearance flight crew : exited adverse environment |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Departed off M39 at XA00Z. I picked up my IFR clearance once airborne and was cleared to osh as filed to 7000 ft. While climbing I asked for 11000 ft to pick up a little better ground speed. I was then cleared to 11000 ft. I reached 11000 ft and started the normal power reduction. I started with reducing the RPM's from 2500 (climb power) to 2300 (cruise power). The manifold pressure was full forward and left full forward (about 21 inches). When I started to lean out the engines (14 gal/side), the engines started to surge in and out with power. I immediately pushed the mixtures back to full rich. The engines continued to surge so I switched the auxiliary fuel boost pumps to high. The surges were frequent enough and violent enough that I could not maintain a safe airspeed. As the airspeed bled off, I immediately started a descent to establish a safe airspeed. The control frequency was congested, however, as soon as I could break in I informed ZME on 119.25 that I was descending. Memphis asked why I was leaving my assigned altitude of 11000 ft and what altitude I was presently at. I stated that my engines were surging and that I needed to descend to maintain a safe airspeed, and that I was presently passing through 9500 ft. However, I was really at 10500 ft (I was paying too much attention to the RPM's and the manifold pressure and did not look at the altimeter close enough). Center immediately cleared me to 9000 ft and asked if I needed an airport to land at. I stated that I would like to continue my descent and that the engines were starting to run smoothly again. Once leveled off at 9000 ft, I asked center for 7000 ft. Center again cleared me to 7000 ft. While descending the engines sounded and felt good. I again manipulated the controls to the cruise confign and continued to oshkosh, wi, without further incident. Upon reviewing this situation with our director of operations and our director of maintenance, I learned that I had the mixtures too rich at 11000 ft. I also learned that in the future I need to lean out the engines more at higher altitudes and that turning on the boost pumps probably made the engines surge more. I also reviewed the pilot operations handbook published for the beechcraft barron 58 and learned that I was leaning the fuel to mixture in accordance with the airplane manual.
Original NASA ASRS Text
Title: PLT OF A BEECH BARON, BE58, DSNDED FROM ASSIGNED ALT DUE TO BOTH ENGS 'SURGING' AND LOSING PWR. RPTR FAILED TO ADVISE ATC AT ONCE DUE TO FREQ CONGESTION.
Narrative: DEPARTED OFF M39 AT XA00Z. I PICKED UP MY IFR CLRNC ONCE AIRBORNE AND WAS CLRED TO OSH AS FILED TO 7000 FT. WHILE CLBING I ASKED FOR 11000 FT TO PICK UP A LITTLE BETTER GND SPD. I WAS THEN CLRED TO 11000 FT. I REACHED 11000 FT AND STARTED THE NORMAL PWR REDUCTION. I STARTED WITH REDUCING THE RPM'S FROM 2500 (CLB PWR) TO 2300 (CRUISE PWR). THE MANIFOLD PRESSURE WAS FULL FORWARD AND L FULL FORWARD (ABOUT 21 INCHES). WHEN I STARTED TO LEAN OUT THE ENGS (14 GAL/SIDE), THE ENGS STARTED TO SURGE IN AND OUT WITH PWR. I IMMEDIATELY PUSHED THE MIXTURES BACK TO FULL RICH. THE ENGS CONTINUED TO SURGE SO I SWITCHED THE AUX FUEL BOOST PUMPS TO HIGH. THE SURGES WERE FREQUENT ENOUGH AND VIOLENT ENOUGH THAT I COULD NOT MAINTAIN A SAFE AIRSPD. AS THE AIRSPD BLED OFF, I IMMEDIATELY STARTED A DSCNT TO ESTABLISH A SAFE AIRSPD. THE CTL FREQ WAS CONGESTED, HOWEVER, AS SOON AS I COULD BREAK IN I INFORMED ZME ON 119.25 THAT I WAS DSNDING. MEMPHIS ASKED WHY I WAS LEAVING MY ASSIGNED ALT OF 11000 FT AND WHAT ALT I WAS PRESENTLY AT. I STATED THAT MY ENGS WERE SURGING AND THAT I NEEDED TO DSND TO MAINTAIN A SAFE AIRSPD, AND THAT I WAS PRESENTLY PASSING THROUGH 9500 FT. HOWEVER, I WAS REALLY AT 10500 FT (I WAS PAYING TOO MUCH ATTN TO THE RPM'S AND THE MANIFOLD PRESSURE AND DID NOT LOOK AT THE ALTIMETER CLOSE ENOUGH). CTR IMMEDIATELY CLRED ME TO 9000 FT AND ASKED IF I NEEDED AN ARPT TO LAND AT. I STATED THAT I WOULD LIKE TO CONTINUE MY DSCNT AND THAT THE ENGS WERE STARTING TO RUN SMOOTHLY AGAIN. ONCE LEVELED OFF AT 9000 FT, I ASKED CTR FOR 7000 FT. CTR AGAIN CLRED ME TO 7000 FT. WHILE DSNDING THE ENGS SOUNDED AND FELT GOOD. I AGAIN MANIPULATED THE CTLS TO THE CRUISE CONFIGN AND CONTINUED TO OSHKOSH, WI, WITHOUT FURTHER INCIDENT. UPON REVIEWING THIS SIT WITH OUR DIRECTOR OF OPS AND OUR DIRECTOR OF MAINT, I LEARNED THAT I HAD THE MIXTURES TOO RICH AT 11000 FT. I ALSO LEARNED THAT IN THE FUTURE I NEED TO LEAN OUT THE ENGS MORE AT HIGHER ALTS AND THAT TURNING ON THE BOOST PUMPS PROBABLY MADE THE ENGS SURGE MORE. I ALSO REVIEWED THE PLT OPS HANDBOOK PUBLISHED FOR THE BEECHCRAFT BARRON 58 AND LEARNED THAT I WAS LEANING THE FUEL TO MIXTURE IN ACCORDANCE WITH THE AIRPLANE MANUAL.
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.