Pilot deviated from assigned altitude due to losing control of the aircraft's altitude in heavy turb...

Attributes
ACN	271680
Time
Date	199405
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mrb
State Reference	WV
Altitude	msl bound lower : 7200 msl bound upper : 8300
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	M-20 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute airway : v143
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : instrument pilot : commercial
Experience	flight time last 90 days : 30 flight time total : 1536
ASRS Report	271680
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

I was cruising in a mooney tls at 165 KIAS at 6000 in IMC on an IFR flight plan from gai to mrb V143 gso. There was a frontal boundary. About 50 mi south of mrb, I began experiencing moderate turbulence. I asked for and was cleared to 8000. Shortly after reaching 8000 I hit an area of increasing turbulence -- up 300 ft, down to 8000 ft, then up 300 and then violently down 800 ft to 7200 ft. I extended the speed brakes and reduced power to slow towards the maneuvering speed of about 120 KIAS. Then I called center, reported 'more than moderate turbulence,' and announced I was unable to hold altitude plus or minus 300 ft. The controller responded: 'yes, you'll have that all the way down to lynchburg.' so I asked for and was cleared to 14000. I donned oxygen and climbed to 14000, where there was no further turbulence. I am unaware of my collision hazard created by the altitude deviation. I've got a stormscope, but not doppler radar. The lesson I learned is to slow down via speed brakes and power reduction when encountering moderate turbulence near a frontal zone. If it suddenly gets worse, far better to be at, or at least near, va.

Original NASA ASRS Text

Title: PLT DEVIATED FROM ASSIGNED ALT DUE TO LOSING CTL OF THE ACFT'S ALT IN HVY TURB.

Narrative: I WAS CRUISING IN A MOONEY TLS AT 165 KIAS AT 6000 IN IMC ON AN IFR FLT PLAN FROM GAI TO MRB V143 GSO. THERE WAS A FRONTAL BOUNDARY. ABOUT 50 MI S OF MRB, I BEGAN EXPERIENCING MODERATE TURB. I ASKED FOR AND WAS CLRED TO 8000. SHORTLY AFTER REACHING 8000 I HIT AN AREA OF INCREASING TURB -- UP 300 FT, DOWN TO 8000 FT, THEN UP 300 AND THEN VIOLENTLY DOWN 800 FT TO 7200 FT. I EXTENDED THE SPD BRAKES AND REDUCED PWR TO SLOW TOWARDS THE MANEUVERING SPD OF ABOUT 120 KIAS. THEN I CALLED CTR, RPTED 'MORE THAN MODERATE TURB,' AND ANNOUNCED I WAS UNABLE TO HOLD ALT PLUS OR MINUS 300 FT. THE CTLR RESPONDED: 'YES, YOU'LL HAVE THAT ALL THE WAY DOWN TO LYNCHBURG.' SO I ASKED FOR AND WAS CLRED TO 14000. I DONNED OXYGEN AND CLBED TO 14000, WHERE THERE WAS NO FURTHER TURB. I AM UNAWARE OF MY COLLISION HAZARD CREATED BY THE ALTDEV. I'VE GOT A STORMSCOPE, BUT NOT DOPPLER RADAR. THE LESSON I LEARNED IS TO SLOW DOWN VIA SPD BRAKES AND PWR REDUCTION WHEN ENCOUNTERING MODERATE TURB NEAR A FRONTAL ZONE. IF IT SUDDENLY GETS WORSE, FAR BETTER TO BE AT, OR AT LEAST NEAR, VA.

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.

Pilot deviated from assigned altitude due to losing control of the aircraft's altitude in heavy turbulence.