C182 pilot unable to maintain assigned altitude.

Attributes
ACN	436971
Time
Date	199905
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : trm.vortac
State Reference	CA
Altitude	msl single value : 9000
Environment
Flight Conditions	VMC
Weather Elements	Windshear Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc tower : sfo.tower
Operator	general aviation : personal
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	cruise : level
Route In Use	enroute airway : v208.airway
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zla.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot oversight : pic
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 60 flight time total : 3000 flight time type : 2800
ASRS Report	436971
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : turbulence non adherence : clearance non adherence : far
Independent Detector	atc equipment other atc equipment : radar other controllera other flight crewa
Resolutory Action	controller : issued alert flight crew : returned to original clearance
Consequence	faa : assigned or threatened penalties
Factors
Maintenance	performance deficiency : repair
Supplementary
Problem Areas	Aircraft Weather Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Recent repair of altimeter (2 weeks ago) for 500 ft deviation and no apparent problem thereafter on 5 hour IFR trips. Assigned 9000 ft by center. Turbulence, shear, updrafts/downdrafts 800 FPM. +40-50 KT tailwind and new altimeter from ZLA required a 250 ft climb. Received psp ATIS and used their altimeter setting. Required further climb in an attempt to maintain 9000 ft, but encountered turbulence updraft and it also appeared to be that I was too low because I could not see beyond or over the top of the mountain ridges. I requested a block altitude 9000-10000 ft but was denied. I tried to maintain 9000 ft but windshear, TAS changed from 130 KTS to 100 KTS and updrafts, then I heard ZLA say 'you are 500 ft high, near XXXX aircraft at 10000 ft.' I did not see the plane or was advised to deviate or change my heading, which probably would have been appropriate if there was a conflict.

Original NASA ASRS Text

Title: C182 PLT UNABLE TO MAINTAIN ASSIGNED ALT.

Narrative: RECENT REPAIR OF ALTIMETER (2 WKS AGO) FOR 500 FT DEV AND NO APPARENT PROB THEREAFTER ON 5 HR IFR TRIPS. ASSIGNED 9000 FT BY CTR. TURB, SHEAR, UPDRAFTS/DOWNDRAFTS 800 FPM. +40-50 KT TAILWIND AND NEW ALTIMETER FROM ZLA REQUIRED A 250 FT CLB. RECEIVED PSP ATIS AND USED THEIR ALTIMETER SETTING. REQUIRED FURTHER CLB IN AN ATTEMPT TO MAINTAIN 9000 FT, BUT ENCOUNTERED TURB UPDRAFT AND IT ALSO APPEARED TO BE THAT I WAS TOO LOW BECAUSE I COULD NOT SEE BEYOND OR OVER THE TOP OF THE MOUNTAIN RIDGES. I REQUESTED A BLOCK ALT 9000-10000 FT BUT WAS DENIED. I TRIED TO MAINTAIN 9000 FT BUT WINDSHEAR, TAS CHANGED FROM 130 KTS TO 100 KTS AND UPDRAFTS, THEN I HEARD ZLA SAY 'YOU ARE 500 FT HIGH, NEAR XXXX ACFT AT 10000 FT.' I DID NOT SEE THE PLANE OR WAS ADVISED TO DEVIATE OR CHANGE MY HDG, WHICH PROBABLY WOULD HAVE BEEN APPROPRIATE IF THERE WAS A CONFLICT.

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.