GA small aircraft altitude deviation excursion from clearance altitude and deviation from clearance ...

Attributes
ACN	91250
Time
Date	198806
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tph
State Reference	NV
Altitude	msl bound lower : 12600 msl bound upper : 13400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 75 flight time total : 200
ASRS Report	91250
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : unable none taken : anomaly accepted
Consequence	faa : investigated faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I have been notified that an investigation is being initialed concerning 2 matters associated with this flight. One is of no concern. However, 2 others are collectively referred to as 'deviations from far's.' I was flying under VFR conditions from sac to las, when I encountered moderate to severe up and down drafts over the sierras. I made an attempt to make a PIREP. I could not hold altitude to within 100' of my assigned altitude. I felt that it was safer for me to concentrate on level attitude and maintain altitude to within about 400', which was possible. Later I encountered an additional impediment--2 thunderheads directly in my path. I notified center of this and requested deviation to the right of course. They instructed me to climb to 15000'. I was not able to comply as I was at maximum power and climb airspeed and losing 200-500 FPM. As I got within about 1 mi of the cumulus clouds I deviated to the right of course and asked for vectors for the nearest clear airport. Upon landing in tph I was informed that I had numerous deviations from far's and would have to answer to FAA. I feel the deviations were needed due to conditions and I acted in the interest of safety for myself and the plane.

Original NASA ASRS Text

Title: GA SMA ALT DEVIATION EXCURSION FROM CLRNC ALT AND DEVIATION FROM CLRNC ROUTE.

Narrative: I HAVE BEEN NOTIFIED THAT AN INVESTIGATION IS BEING INITIALED CONCERNING 2 MATTERS ASSOCIATED WITH THIS FLT. ONE IS OF NO CONCERN. HOWEVER, 2 OTHERS ARE COLLECTIVELY REFERRED TO AS 'DEVIATIONS FROM FAR'S.' I WAS FLYING UNDER VFR CONDITIONS FROM SAC TO LAS, WHEN I ENCOUNTERED MODERATE TO SEVERE UP AND DOWN DRAFTS OVER THE SIERRAS. I MADE AN ATTEMPT TO MAKE A PIREP. I COULD NOT HOLD ALT TO WITHIN 100' OF MY ASSIGNED ALT. I FELT THAT IT WAS SAFER FOR ME TO CONCENTRATE ON LEVEL ATTITUDE AND MAINTAIN ALT TO WITHIN ABOUT 400', WHICH WAS POSSIBLE. LATER I ENCOUNTERED AN ADDITIONAL IMPEDIMENT--2 THUNDERHEADS DIRECTLY IN MY PATH. I NOTIFIED CENTER OF THIS AND REQUESTED DEVIATION TO THE RIGHT OF COURSE. THEY INSTRUCTED ME TO CLB TO 15000'. I WAS NOT ABLE TO COMPLY AS I WAS AT MAX PWR AND CLB AIRSPD AND LOSING 200-500 FPM. AS I GOT WITHIN ABOUT 1 MI OF THE CUMULUS CLOUDS I DEVIATED TO THE RIGHT OF COURSE AND ASKED FOR VECTORS FOR THE NEAREST CLEAR ARPT. UPON LNDG IN TPH I WAS INFORMED THAT I HAD NUMEROUS DEVIATIONS FROM FAR'S AND WOULD HAVE TO ANSWER TO FAA. I FEEL THE DEVIATIONS WERE NEEDED DUE TO CONDITIONS AND I ACTED IN THE INTEREST OF SAFETY FOR MYSELF AND THE PLANE.

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

GA small aircraft altitude deviation excursion from clearance altitude and deviation from clearance route.