Rough running engine on BE36 results in precautionary landing and discovery of an unattached turbo p...

Narrative:

On a flight the pilot had requested and received flight following. While flying at 5500 ft; approximately 30 mins into the flight the aircraft engine suddenly started to surge violently. The pilot immediately switched fuel tanks; went to full rich on the mixture; throttling back; lowered the RPM; and turned the electrical fuel pump on and off; all of which didn't stop the surging. The pilot called TRACON and declared an emergency. TRACON told him that the ZZZ airport was 7 mi and 11 O'clock position. The pilot obtained visual contact with the airport and turned and headed that direction. TRACON said the wind was calm and they were using runway xx. By this time the aircraft was down to 3500 ft and the surge had stopped. The pilot told TRACON what was going on to ZZZ; as there is no service at ZZZ. However; the surge returned and the pilot told TRACON that he was going to land on runway xy as there wasn't any wind or traffic. The landing was normal and as TRACON couldn't hear the pilot on the ground another airborne pilot relayed the message that the aircraft was down safely. The pilot taxied to the ramp and shut down the engine; got out and inspected the aircraft and found no leaks or damage. Lifting the left cowl the pilot found a brown hose completely disconnected. The pilot called his aircraft mechanic by cell phone and from the description of the hose and the location of the connecting fitting the aircraft mechanic concluded that this was the upper deck hose for the turbo pressure regulator. Using a pair of channel locks that were in the aircraft the pilot was able to reattach and tighten the hose on the fitting which is down stream of the turbo. After starting the engine and per the pilot's aircraft mechanic instructions he ran the engine to full power for about 10 seconds; to verify that everything appeared normal. After taking off the pilot again contacted TRACON for flight following. TRACON asked what had caused the surge problem and the pilot told them about the disconnected hose and stated that everything was operating normally. Approximately 25 mins later the aircraft made a normal landing at ZZZ2.

Original NASA ASRS Text

Title: ROUGH RUNNING ENGINE ON BE36 RESULTS IN PRECAUTIONARY LANDING AND DISCOVERY OF AN UNATTACHED TURBO PRESSURE REGULATOR HOSE. ON SITE REPAIR ACCOMPLISHED.

Narrative: ON A FLT THE PLT HAD REQUESTED AND RECEIVED FLT FOLLOWING. WHILE FLYING AT 5500 FT; APPROX 30 MINS INTO THE FLT THE ACFT ENG SUDDENLY STARTED TO SURGE VIOLENTLY. THE PLT IMMEDIATELY SWITCHED FUEL TANKS; WENT TO FULL RICH ON THE MIXTURE; THROTTLING BACK; LOWERED THE RPM; AND TURNED THE ELECTRICAL FUEL PUMP ON AND OFF; ALL OF WHICH DIDN'T STOP THE SURGING. THE PLT CALLED TRACON AND DECLARED AN EMER. TRACON TOLD HIM THAT THE ZZZ ARPT WAS 7 MI AND 11 O'CLOCK POS. THE PLT OBTAINED VISUAL CONTACT WITH THE ARPT AND TURNED AND HEADED THAT DIRECTION. TRACON SAID THE WIND WAS CALM AND THEY WERE USING RWY XX. BY THIS TIME THE ACFT WAS DOWN TO 3500 FT AND THE SURGE HAD STOPPED. THE PLT TOLD TRACON WHAT WAS GOING ON TO ZZZ; AS THERE IS NO SVC AT ZZZ. HOWEVER; THE SURGE RETURNED AND THE PLT TOLD TRACON THAT HE WAS GOING TO LAND ON RWY XY AS THERE WASN'T ANY WIND OR TFC. THE LNDG WAS NORMAL AND AS TRACON COULDN'T HEAR THE PLT ON THE GND ANOTHER AIRBORNE PLT RELAYED THE MESSAGE THAT THE ACFT WAS DOWN SAFELY. THE PLT TAXIED TO THE RAMP AND SHUT DOWN THE ENG; GOT OUT AND INSPECTED THE ACFT AND FOUND NO LEAKS OR DAMAGE. LIFTING THE L COWL THE PLT FOUND A BROWN HOSE COMPLETELY DISCONNECTED. THE PLT CALLED HIS ACFT MECH BY CELL PHONE AND FROM THE DESCRIPTION OF THE HOSE AND THE LOCATION OF THE CONNECTING FITTING THE ACFT MECH CONCLUDED THAT THIS WAS THE UPPER DECK HOSE FOR THE TURBO PRESSURE REGULATOR. USING A PAIR OF CHANNEL LOCKS THAT WERE IN THE ACFT THE PLT WAS ABLE TO REATTACH AND TIGHTEN THE HOSE ON THE FITTING WHICH IS DOWN STREAM OF THE TURBO. AFTER STARTING THE ENG AND PER THE PLT'S ACFT MECH INSTRUCTIONS HE RAN THE ENG TO FULL PWR FOR ABOUT 10 SECONDS; TO VERIFY THAT EVERYTHING APPEARED NORMAL. AFTER TAKING OFF THE PLT AGAIN CONTACTED TRACON FOR FLT FOLLOWING. TRACON ASKED WHAT HAD CAUSED THE SURGE PROB AND THE PLT TOLD THEM ABOUT THE DISCONNECTED HOSE AND STATED THAT EVERYTHING WAS OPERATING NORMALLY. APPROX 25 MINS LATER THE ACFT MADE A NORMAL LNDG AT ZZZ2.

Data retrieved from NASA's ASRS site as of January 2009 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.

Attributes
ACN	755568
Time
Date	20070911
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 5500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	general aviation : personal
Make Model Name	Bonanza 36
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 6 flight time total : 3774 flight time type : 3417
ASRS Report	755568
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed as precaution flight crew : declared emergency
Consequence	other
Supplementary
Problem Areas	Maintenance Human Performance Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Rough running engine on BE36 results in precautionary landing and discovery of an unattached turbo pressure regulator hose. On site repair accomplished.