An MD88 encounters wake turbulence at FL340 that induced a buffet; roll and loss of altitude.

Attributes
ACN	806689
Time
Date	200809
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : fmy.airport
State Reference	FL
Altitude	msl single value : 34000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma.artcc
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : multi engine pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 160 flight time total : 14000 flight time type : 3257
ASRS Report	806689
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : wake turbulence
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control
Supplementary
Problem Areas	Environmental Factor
Primary Problem	Environmental Factor

Narrative:

While turning to fix; leveling off with throttles coming back; aircraft hit wake turbulence rolled to right; aircraft buffeted; autoplt did its best to control it and I didn't turn it off. Aircraft settled 200-300 ft low and corrected back to altitude. Did not get any stall warning during event; but was shown (by this event) that MD88 is not a solid performer at high altitude. Our policy now is to fly slow to save gas; ie; .74 mach instead of .76 mach; which gives a lot less margin in wake turbulence at altitude.

Original NASA ASRS Text

Title: AN MD88 ENCOUNTERS WAKE TURB AT FL340 THAT INDUCED A BUFFET; ROLL AND LOSS OF ALTITUDE.

Narrative: WHILE TURNING TO FIX; LEVELING OFF WITH THROTTLES COMING BACK; ACFT HIT WAKE TURB ROLLED TO RIGHT; ACFT BUFFETED; AUTOPLT DID ITS BEST TO CONTROL IT AND I DIDN'T TURN IT OFF. ACFT SETTLED 200-300 FT LOW AND CORRECTED BACK TO ALT. DID NOT GET ANY STALL WARNING DURING EVENT; BUT WAS SHOWN (BY THIS EVENT) THAT MD88 IS NOT A SOLID PERFORMER AT HIGH ALT. OUR POLICY NOW IS TO FLY SLOW TO SAVE GAS; IE; .74 MACH INSTEAD OF .76 MACH; WHICH GIVES A LOT LESS MARGIN IN WAKE TURB AT ALT.

Data retrieved from NASA's ASRS site as of May 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.