Air carrier heavy transport encounters rain at FL330 and -26 degrees centigrade RAT.

Attributes
ACN	145902
Time
Date	199005
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : obh
State Reference	NE
Altitude	msl bound lower : 32200 msl bound upper : 33000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp tracon : oak
Operator	common carrier : air carrier
Make Model Name	Heavy Transport, Low Wing, 4 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : zmp
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : private pilot : commercial pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 2500
ASRS Report	145902
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : overcame equipment problem flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

In cruise at FL330, autoplt inoperative, no radar echos, encountered light to moderate turbulence. Ram air temperature was -26 degrees. Encountered moderate to heavy rain! Engine and wing anti-ice had been previously turned on when small amount of ice was detected. Airspeed suddenly dropped about 30 KTS at which time power was called for by PF and was applied. Airspeed loss of an additional 80 KTS was noted!, and I then pressed nose down to regain speed. In 4-10 seconds airspeed was regained back to about 290 KTS, but altitude was lost to about FL320-322. The aircraft attitude was never nose up and no control was ever lost. The crew concurred that the icing was severe enough that the pitot tubes were blocked! Then, after the 5-10 seconds melted free. In general attitude was flown which prevented a drastic pushover to regain speed during which the high speed limits would have been exceeded. I have never seen an operating pitot ice over this was in my 27 yrs of flying. The pitots both had ice on them for at least 15 mins after this occurrence. At FL330 with airspeed indicating 140, it is hard to overcome one's 'speed is life' training! I'm sure glad I did not jam the nose down!

Original NASA ASRS Text

Title: ACR HVT ENCOUNTERS RAIN AT FL330 AND -26 DEGREES CENTIGRADE RAT.

Narrative: IN CRUISE AT FL330, AUTOPLT INOP, NO RADAR ECHOS, ENCOUNTERED LIGHT TO MODERATE TURB. RAM AIR TEMP WAS -26 DEGS. ENCOUNTERED MODERATE TO HEAVY RAIN! ENG AND WING ANTI-ICE HAD BEEN PREVIOUSLY TURNED ON WHEN SMALL AMOUNT OF ICE WAS DETECTED. AIRSPD SUDDENLY DROPPED ABOUT 30 KTS AT WHICH TIME PWR WAS CALLED FOR BY PF AND WAS APPLIED. AIRSPD LOSS OF AN ADDITIONAL 80 KTS WAS NOTED!, AND I THEN PRESSED NOSE DOWN TO REGAIN SPD. IN 4-10 SECS AIRSPD WAS REGAINED BACK TO ABOUT 290 KTS, BUT ALT WAS LOST TO ABOUT FL320-322. THE ACFT ATTITUDE WAS NEVER NOSE UP AND NO CONTROL WAS EVER LOST. THE CREW CONCURRED THAT THE ICING WAS SEVERE ENOUGH THAT THE PITOT TUBES WERE BLOCKED! THEN, AFTER THE 5-10 SECS MELTED FREE. IN GENERAL ATTITUDE WAS FLOWN WHICH PREVENTED A DRASTIC PUSHOVER TO REGAIN SPD DURING WHICH THE HIGH SPD LIMITS WOULD HAVE BEEN EXCEEDED. I HAVE NEVER SEEN AN OPERATING PITOT ICE OVER THIS WAS IN MY 27 YRS OF FLYING. THE PITOTS BOTH HAD ICE ON THEM FOR AT LEAST 15 MINS AFTER THIS OCCURRENCE. AT FL330 WITH AIRSPD INDICATING 140, IT IS HARD TO OVERCOME ONE'S 'SPD IS LIFE' TRNING! I'M SURE GLAD I DID NOT JAM THE NOSE DOWN!

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.