Small aircraft encounters strong winds with vertical action. Unable to hold altitude.

Attributes
ACN	289740
Time
Date	199411
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ths
State Reference	PA
Altitude	msl bound lower : 5500 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct enroute airway : zny
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 40 flight time total : 350 flight time type : 200
ASRS Report	289740
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	inflight encounter other other anomaly
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

While flying level at 6000 ft VMC, I encountered wind conditions stronger than forecast, over mountainous terrain. A heavy downdraft was then encountered and the sudden loss of 500 ft of altitude followed. I was able to then hold altitude at 5500 ft by setting the plane in a full power climb confign but was unable to climb. Within a few mins I canceled IFR and returned to home base and landed VFR.

Original NASA ASRS Text

Title: SMA ENCOUNTERS STRONG WINDS WITH VERT ACTION. UNABLE TO HOLD ALT.

Narrative: WHILE FLYING LEVEL AT 6000 FT VMC, I ENCOUNTERED WIND CONDITIONS STRONGER THAN FORECAST, OVER MOUNTAINOUS TERRAIN. A HVY DOWNDRAFT WAS THEN ENCOUNTERED AND THE SUDDEN LOSS OF 500 FT OF ALT FOLLOWED. I WAS ABLE TO THEN HOLD ALT AT 5500 FT BY SETTING THE PLANE IN A FULL PWR CLB CONFIGN BUT WAS UNABLE TO CLB. WITHIN A FEW MINS I CANCELED IFR AND RETURNED TO HOME BASE AND LANDED VFR.

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.