A B757-200 in cruise at FL320 entered area of moderate turbulence. Captain's pitot static systems failed. Made 20 degree course change. Systems returned to normal. Suspect static port icing when passing through thunderstorm.

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Attributes
ACN	695401
Time
Date	200604
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : ggg.vortac
State Reference	TX
Altitude	msl single value : 32000
Environment
Flight Conditions	IMC
Weather Elements	Rain Thunderstorm Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	695401
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : weather
Independent Detector	aircraft equipment other aircraft equipment : eicas other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated flight crew : exited adverse environment flight crew : overcame equipment problem
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Weather
Primary Problem	Aircraft

Narrative:

At FL320 in cruise in IMC conditions. 80 mi range only light/moderate precipitation noted on radar. Entered area of moderate turbulence. Captain's airspeed decreased rapidly to 140 KTS. First officer's normal at 290 KTS. Autoplt tripped off. Rudder ratio EICAS message. Airspeed disagree EICAS message; no flight director. Hand flew (disconnected autothrottles and referenced first officer's airspeed indicator) and made an immediate 20 degree off course turn to the right to avoid buildup. Altitude maintained within 150 ft during the turbulence. Altitude; airspeed; rudder ratio; and as disagree went off and then came back on intermittently. Center notified of deviation. When in clear; aircraft returned to normal. Looking back to my left I could see a pretty significant buildup associated with a line of thunderstorms we had just exited. Definitely more intense than we were painting on the radar. Suspect ice buildup on captain's static port.

Original NASA ASRS Text

Title: A B757-200 IN CRUISE AT FL320 ENTERED AREA OF MODERATE TURBULENCE. CAPTAIN'S PITOT STATIC SYSTEMS FAILED. MADE 20 DEGREE COURSE CHANGE. SYSTEMS RETURNED TO NORMAL. SUSPECT STATIC PORT ICING WHEN PASSING THROUGH THUNDERSTORM.

Narrative: AT FL320 IN CRUISE IN IMC CONDITIONS. 80 MI RANGE ONLY LIGHT/MODERATE PRECIP NOTED ON RADAR. ENTERED AREA OF MODERATE TURB. CAPT'S AIRSPEED DECREASED RAPIDLY TO 140 KTS. FO'S NORMAL AT 290 KTS. AUTOPLT TRIPPED OFF. RUDDER RATIO EICAS MESSAGE. AIRSPEED DISAGREE EICAS MESSAGE; NO FLT DIRECTOR. HAND FLEW (DISCONNECTED AUTOTHROTTLES AND REFERENCED FO'S AIRSPEED INDICATOR) AND MADE AN IMMEDIATE 20 DEG OFF COURSE TURN TO THE RIGHT TO AVOID BUILDUP. ALT MAINTAINED WITHIN 150 FT DURING THE TURB. ALT; AIRSPEED; RUDDER RATIO; AND AS DISAGREE WENT OFF AND THEN CAME BACK ON INTERMITTENTLY. CTR NOTIFIED OF DEV. WHEN IN CLEAR; ACFT RETURNED TO NORMAL. LOOKING BACK TO MY LEFT I COULD SEE A PRETTY SIGNIFICANT BUILDUP ASSOCIATED WITH A LINE OF TSTMS WE HAD JUST EXITED. DEFINITELY MORE INTENSE THAN WE WERE PAINTING ON THE RADAR. SUSPECT ICE BUILDUP ON CAPT'S STATIC PORT.

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.