Cessna P210 pilot has vacuum system fail and aircraft has altitude excursion.

Attributes
ACN	698988
Time
Date	200605
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ztl.artcc
State Reference	GA
Altitude	msl single value : 13000
Environment
Flight Conditions	Mixed
Weather Elements	Thunderstorm Windshear Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc
Operator	general aviation : corporate
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C 210D
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : ztl.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : level
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 300 flight time total : 9000 flight time type : 750
ASRS Report	698988
Person 2
Affiliation	government : faa
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment other aircraft equipment : attitude indicator other flight crewa
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude flight crew : overcame equipment problem
Consequence	faa : reviewed incident with flight crew other
Miss Distance	horizontal : 0 vertical : 600
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

En route from bna airport to jqf airport; near the time stated above in cruise with the autoplt engaged; I was given permission for heading deviations 'as needed' for navigation around active thunderstorm cells. During the time I was circumnaving a cumulo nimbus cell; the aircraft entered an extreme nose down pitch altitude; excessive back pressure was applied and the autoplt disengaged. After the autoplt was disengaged; I was able to regain pitch control and retrim the aircraft from its full nose down setting. As I was returning to 13000 ft; I noticed false indications from the attitude indicator and no suction. The attitude indicator is the only primary instrument on this aircraft operated from vacuum and the 'fcs' receives pitch information from the attitude indicator. The directional gyro is slaved. Leveling back at 13000 ft I advised ZTL that I had a vacuum failure and needed to stay clear of the clouds as much as possible. I was told that there was crossing traffic at 12000 ft and that a pilot deviation of 400 ft had occurred and to call them. The flight was continued partial panel to jqf airport. Maintenance personnel were contacted to troubleshoot the duel vacuum system. Both vacuum pumps were found to be sheared at the shaft and the vacuum out indicators were inoperative. Repairs were made and the aircraft returned to service with a note on the shut down checklist to check the vacuum out indicators after engine shutdown.

Original NASA ASRS Text

Title: CESSNA P210 PLT HAS VACUUM SYS FAIL AND ACFT HAS ALT EXCURSION.

Narrative: ENRTE FROM BNA ARPT TO JQF ARPT; NEAR THE TIME STATED ABOVE IN CRUISE WITH THE AUTOPLT ENGAGED; I WAS GIVEN PERMISSION FOR HDG DEVS 'AS NEEDED' FOR NAV AROUND ACTIVE TSTM CELLS. DURING THE TIME I WAS CIRCUMNAVING A CUMULO NIMBUS CELL; THE ACFT ENTERED AN EXTREME NOSE DOWN PITCH ALT; EXCESSIVE BACK PRESSURE WAS APPLIED AND THE AUTOPLT DISENGAGED. AFTER THE AUTOPLT WAS DISENGAGED; I WAS ABLE TO REGAIN PITCH CTL AND RETRIM THE ACFT FROM ITS FULL NOSE DOWN SETTING. AS I WAS RETURNING TO 13000 FT; I NOTICED FALSE INDICATIONS FROM THE ATTITUDE INDICATOR AND NO SUCTION. THE ATTITUDE INDICATOR IS THE ONLY PRIMARY INST ON THIS ACFT OPERATED FROM VACUUM AND THE 'FCS' RECEIVES PITCH INFO FROM THE ATTITUDE INDICATOR. THE DIRECTIONAL GYRO IS SLAVED. LEVELING BACK AT 13000 FT I ADVISED ZTL THAT I HAD A VACUUM FAILURE AND NEEDED TO STAY CLR OF THE CLOUDS AS MUCH AS POSSIBLE. I WAS TOLD THAT THERE WAS XING TFC AT 12000 FT AND THAT A PLTDEV OF 400 FT HAD OCCURRED AND TO CALL THEM. THE FLT WAS CONTINUED PARTIAL PANEL TO JQF ARPT. MAINT PERSONNEL WERE CONTACTED TO TROUBLESHOOT THE DUEL VACUUM SYS. BOTH VACUUM PUMPS WERE FOUND TO BE SHEARED AT THE SHAFT AND THE VACUUM OUT INDICATORS WERE INOP. REPAIRS WERE MADE AND THE ACFT RETURNED TO SVC WITH A NOTE ON THE SHUT DOWN CHKLIST TO CHK THE VACUUM OUT INDICATORS AFTER ENG SHUTDOWN.

Data retrieved from NASA's ASRS site as of January 2009 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.