GA small aircraft made a takeoff on a training flight with clogged pitot static system.

Attributes
ACN	117282
Time
Date	198907
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : 2b4
State Reference	RI
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : takeoff ground : preflight landing other
Flight Plan	None
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 1800 flight time type : 10
ASRS Report	117282
Person 2
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : student
Events
Anomaly	aircraft equipment problem : critical non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft was parked on the grass, which had been cut the day before. Small aircraft was owned by the student who is usually meticulous about the preflight. As we rotated I noticed student staring at the airspeed indicator. I looked over and it read 160 KTS. There was a questionable amount of runway left, so I took the aircraft and made an uneventful landing on the 3000' strip. (I had no brakes on my side so I felt it better to take if around and land.) we went to the far end of the ramp and shut down. Both the pitot tube and drain hole were clogged with grass. We blew the grass out, however, it still read 160 KTS on the airspeed indicator. I should mention during climbout the airspeed indicator pegged on red line (around 200). In retrospect, I can't believe I didn't think to make a special check of the pitot static system as we walked on the fresh cut grass. I'm sure this experience was worth a thousand words about the importance of preflting properly, and I learned not to take anything for granted. I still can't figure out why the airspeed indicator didn't go back to 0 after we blew the grass out.

Original NASA ASRS Text

Title: GA SMA MADE A TKOF ON A TRAINING FLT WITH CLOGGED PITOT STATIC SYSTEM.

Narrative: ACFT WAS PARKED ON THE GRASS, WHICH HAD BEEN CUT THE DAY BEFORE. SMA WAS OWNED BY THE STUDENT WHO IS USUALLY METICULOUS ABOUT THE PREFLT. AS WE ROTATED I NOTICED STUDENT STARING AT THE AIRSPEED INDICATOR. I LOOKED OVER AND IT READ 160 KTS. THERE WAS A QUESTIONABLE AMOUNT OF RWY LEFT, SO I TOOK THE ACFT AND MADE AN UNEVENTFUL LNDG ON THE 3000' STRIP. (I HAD NO BRAKES ON MY SIDE SO I FELT IT BETTER TO TAKE IF AROUND AND LAND.) WE WENT TO THE FAR END OF THE RAMP AND SHUT DOWN. BOTH THE PITOT TUBE AND DRAIN HOLE WERE CLOGGED WITH GRASS. WE BLEW THE GRASS OUT, HOWEVER, IT STILL READ 160 KTS ON THE AIRSPEED INDICATOR. I SHOULD MENTION DURING CLIMBOUT THE AIRSPEED INDICATOR PEGGED ON RED LINE (AROUND 200). IN RETROSPECT, I CAN'T BELIEVE I DIDN'T THINK TO MAKE A SPECIAL CHECK OF THE PITOT STATIC SYSTEM AS WE WALKED ON THE FRESH CUT GRASS. I'M SURE THIS EXPERIENCE WAS WORTH A THOUSAND WORDS ABOUT THE IMPORTANCE OF PREFLTING PROPERLY, AND I LEARNED NOT TO TAKE ANYTHING FOR GRANTED. I STILL CAN'T FIGURE OUT WHY THE AIRSPEED INDICATOR DIDN'T GO BACK TO 0 AFTER WE BLEW THE GRASS OUT.

Data retrieved from NASA's ASRS site as of August 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.