MD88 crew experiences prestall buffet at FL350.

Attributes
ACN	435673
Time
Date	199904
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : rod.vortac
State Reference	OH
Altitude	msl bound lower : 33000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc tower : san.tower
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 9500 flight time type : 3500
ASRS Report	435673
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 100 flight time total : 7500 flight time type : 700
ASRS Report	435498
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment
Supplementary
Problem Areas	Aircraft ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were level at FL310 heading 225 degrees talking to ZID. Center cleared us to climb to FL350, to be there in 4 mins or less. FMS cruise page indicated FL350 was a good cruise altitude. We traded speed for altitude to make the altitude clearance, with the time restr. Reaching FL350 our speed was approximately 240 KTS. We started experiencing slight airframe buffeting and assumed at first that it was just clear air turbulence. Then the airspeed began to decrease and would not recover with full power set. The first officer was flying the aircraft. He disconnected the autoplt and began a descent at my command as we realized this was approach to a stall buffet. I asked center for clearance to FL330, but ATC said to maintain FL350. I told him we were unable and had to descend. ATC assigned us FL330 and a left turn to 180 degrees.

Original NASA ASRS Text

Title: MD88 CREW EXPERIENCES PRESTALL BUFFET AT FL350.

Narrative: WE WERE LEVEL AT FL310 HDG 225 DEGS TALKING TO ZID. CTR CLRED US TO CLB TO FL350, TO BE THERE IN 4 MINS OR LESS. FMS CRUISE PAGE INDICATED FL350 WAS A GOOD CRUISE ALT. WE TRADED SPD FOR ALT TO MAKE THE ALT CLRNC, WITH THE TIME RESTR. REACHING FL350 OUR SPD WAS APPROX 240 KTS. WE STARTED EXPERIENCING SLIGHT AIRFRAME BUFFETING AND ASSUMED AT FIRST THAT IT WAS JUST CLR AIR TURB. THEN THE AIRSPD BEGAN TO DECREASE AND WOULD NOT RECOVER WITH FULL PWR SET. THE FO WAS FLYING THE ACFT. HE DISCONNECTED THE AUTOPLT AND BEGAN A DSCNT AT MY COMMAND AS WE REALIZED THIS WAS APCH TO A STALL BUFFET. I ASKED CTR FOR CLRNC TO FL330, BUT ATC SAID TO MAINTAIN FL350. I TOLD HIM WE WERE UNABLE AND HAD TO DSND. ATC ASSIGNED US FL330 AND A L TURN TO 180 DEGS.

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.