An air carrier MD80 pilot reports compressor stalls at FL350. The reporter was unable to maintain altitude while deviating around thunderstorms. WX factors embedded thunderstorm producing moderate turbulence and moderate rain.

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Attributes
ACN	347261
Time
Date	199609
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hln
State Reference	MT
Altitude	msl bound lower : 31000 msl bound upper : 35000
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zlc tower : las
Operator	common carrier : air carrier
Make Model Name	MD-83
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	347261
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : far non adherence : clearance other anomaly other
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Aircraft at FL350, weight: 126500 pounds, MD83. Saw embedded thunderstorm on radar 45 mi ahead. Asked for and received deviation south of course (upwind side) at about 25 mi. During turn in VMC, aircraft had unusual buzzing sound. Approximately .770 mach. Shortly afterward, still in VMC, autoplt would not hold altitude. At 150 ft low, I disconnected the autoplt. Speed decayed rapidly to about .70 mach. Asked and received clearance to FL310. Began descent in continuous moderate turbulence. Asked first officer to watch engine instruments as I was increasing power to maintain speed during descent. Encountered light to moderate rain. Engine anti-ice was turned on. Deadheading copilot called and reported compressor stalls had occurred on left engine. Level at FL310 in VMC conditions, all engine parameters reported normal. First officer reported no engine instruments looked abnormal at any time. Called and reported incident to dispatch, and also wrote up stalls in logbook upon arrival at sea. Walked around aircraft and inspected engines with mechanic. Nothing abnormal to report at this time.

Original NASA ASRS Text

Title: AN ACR MD80 PLT RPTS COMPRESSOR STALLS AT FL350. THE RPTR WAS UNABLE TO MAINTAIN ALT WHILE DEVIATING AROUND TSTMS. WX FACTORS EMBEDDED TSTM PRODUCING MODERATE TURB AND MODERATE RAIN.

Narrative: ACFT AT FL350, WT: 126500 LBS, MD83. SAW EMBEDDED TSTM ON RADAR 45 MI AHEAD. ASKED FOR AND RECEIVED DEV S OF COURSE (UPWIND SIDE) AT ABOUT 25 MI. DURING TURN IN VMC, ACFT HAD UNUSUAL BUZZING SOUND. APPROX .770 MACH. SHORTLY AFTERWARD, STILL IN VMC, AUTOPLT WOULD NOT HOLD ALT. AT 150 FT LOW, I DISCONNECTED THE AUTOPLT. SPD DECAYED RAPIDLY TO ABOUT .70 MACH. ASKED AND RECEIVED CLRNC TO FL310. BEGAN DSCNT IN CONTINUOUS MODERATE TURB. ASKED FO TO WATCH ENG INSTS AS I WAS INCREASING PWR TO MAINTAIN SPD DURING DSCNT. ENCOUNTERED LIGHT TO MODERATE RAIN. ENG ANTI-ICE WAS TURNED ON. DEADHEADING COPLT CALLED AND RPTED COMPRESSOR STALLS HAD OCCURRED ON L ENG. LEVEL AT FL310 IN VMC CONDITIONS, ALL ENG PARAMETERS RPTED NORMAL. FO RPTED NO ENG INSTS LOOKED ABNORMAL AT ANY TIME. CALLED AND RPTED INCIDENT TO DISPATCH, AND ALSO WROTE UP STALLS IN LOGBOOK UPON ARR AT SEA. WALKED AROUND ACFT AND INSPECTED ENGS WITH MECH. NOTHING ABNORMAL TO RPT AT THIS TIME.

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.