An IFR C210 private pilot gets embroiled with a thunderstorm while IMC at 5000 ft, losing control an...

Attributes
ACN	580991
Time
Date	200305
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : ear.vor
State Reference	NE
Altitude	msl bound lower : 4000 msl bound upper : 5000
Environment
Flight Conditions	IMC
Weather Elements	Turbulence Rain Thunderstorm
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc tower : hpn.tower
Operator	general aviation : personal
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C, 210D
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 25 flight time total : 1560 flight time type : 1100
ASRS Report	580991
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : published procedure non adherence : clearance other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : regained aircraft control
Supplementary
Problem Areas	Weather ATC Facility ATC Human Performance Flight Crew Human Performance
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

I was flying IFR from longview, tx, to oneil, northeast. I had checked with flight service shortly before and was told there were no convective sigmets along my route and no convective activity detected. I had asked for a deviation west of the route to skirt some buildups, that I could see. Upon turning back toward my course I went back into IMC. Approximately 10 mins later I encountered what appeared to be a storm cell with heavy turbulence and rain. I asked for a vector around the worst of it and center responded they couldn't help as they couldn't see any precipitation. I then asked to leave the frequency and check with flight service. They said to fly straight north and I should fly out of it in a few mi. During this time I could not maintain altitude. I slowed the aircraft to maneuvering speed and lost almost 1000 ft. My assigned altitude was 5000 ft. As soon as I went back to center I reported this to them. Shortly after this I came out the north side of the cell into sporadic VFR conditions and climbed back up to 5000 ft. I was then handed off to another controller and he gave me a new altimeter setting of 29.90 which I repeated back to him as it was much different from my previous setting. Shortly after this he reported me to be 600 ft low. I again repeated my altimeter setting of 29.90 and he said it should be 29.41. I reset the altimeter and climbed back to the proper altitude of 5000 ft. My recommendation to help prevent a recurrence is to equipment center with WX radar. This would help rather than trying to go back and forth between center and flight service when WX conditions are changing rapidly. Also about 1 min before I encountered the storm cell, center issued a convective SIGMET that included the area I was flying in but it was issued too late to be of any help to me. If there is any way to speed up the process of issuing these convective sigmets when the WX is changing that may also help. Also I believe that when I read back the new altimeter setting of 29.90 that if this were not the correct setting the center controller should have repeated the proper altimeter setting back to me.

Original NASA ASRS Text

Title: AN IFR C210 PVT PLT GETS EMBROILED WITH A TSTM WHILE IMC AT 5000 FT, LOSING CTL AND ALT TO 4000 FT BEFORE EXITING THE CELL.

Narrative: I WAS FLYING IFR FROM LONGVIEW, TX, TO ONEIL, NE. I HAD CHKED WITH FLT SVC SHORTLY BEFORE AND WAS TOLD THERE WERE NO CONVECTIVE SIGMETS ALONG MY RTE AND NO CONVECTIVE ACTIVITY DETECTED. I HAD ASKED FOR A DEV W OF THE RTE TO SKIRT SOME BUILDUPS, THAT I COULD SEE. UPON TURNING BACK TOWARD MY COURSE I WENT BACK INTO IMC. APPROX 10 MINS LATER I ENCOUNTERED WHAT APPEARED TO BE A STORM CELL WITH HVY TURB AND RAIN. I ASKED FOR A VECTOR AROUND THE WORST OF IT AND CTR RESPONDED THEY COULDN'T HELP AS THEY COULDN'T SEE ANY PRECIPITATION. I THEN ASKED TO LEAVE THE FREQ AND CHK WITH FLT SVC. THEY SAID TO FLY STRAIGHT N AND I SHOULD FLY OUT OF IT IN A FEW MI. DURING THIS TIME I COULD NOT MAINTAIN ALT. I SLOWED THE ACFT TO MANEUVERING SPD AND LOST ALMOST 1000 FT. MY ASSIGNED ALT WAS 5000 FT. AS SOON AS I WENT BACK TO CTR I RPTED THIS TO THEM. SHORTLY AFTER THIS I CAME OUT THE N SIDE OF THE CELL INTO SPORADIC VFR CONDITIONS AND CLBED BACK UP TO 5000 FT. I WAS THEN HANDED OFF TO ANOTHER CTLR AND HE GAVE ME A NEW ALTIMETER SETTING OF 29.90 WHICH I REPEATED BACK TO HIM AS IT WAS MUCH DIFFERENT FROM MY PREVIOUS SETTING. SHORTLY AFTER THIS HE RPTED ME TO BE 600 FT LOW. I AGAIN REPEATED MY ALTIMETER SETTING OF 29.90 AND HE SAID IT SHOULD BE 29.41. I RESET THE ALTIMETER AND CLBED BACK TO THE PROPER ALT OF 5000 FT. MY RECOMMENDATION TO HELP PREVENT A RECURRENCE IS TO EQUIP CTR WITH WX RADAR. THIS WOULD HELP RATHER THAN TRYING TO GO BACK AND FORTH BTWN CTR AND FLT SVC WHEN WX CONDITIONS ARE CHANGING RAPIDLY. ALSO ABOUT 1 MIN BEFORE I ENCOUNTERED THE STORM CELL, CTR ISSUED A CONVECTIVE SIGMET THAT INCLUDED THE AREA I WAS FLYING IN BUT IT WAS ISSUED TOO LATE TO BE OF ANY HELP TO ME. IF THERE IS ANY WAY TO SPD UP THE PROCESS OF ISSUING THESE CONVECTIVE SIGMETS WHEN THE WX IS CHANGING THAT MAY ALSO HELP. ALSO I BELIEVE THAT WHEN I READ BACK THE NEW ALTIMETER SETTING OF 29.90 THAT IF THIS WERE NOT THE CORRECT SETTING THE CTR CTLR SHOULD HAVE REPEATED THE PROPER ALTIMETER SETTING BACK TO ME.

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.

An IFR C210 private pilot gets embroiled with a thunderstorm while IMC at 5000 ft, losing control and altitude to 4000 ft before exiting the cell.