Discovered first officer's airspeed unreliable at V1. Flight continued to destination.

Attributes
ACN	94911
Time
Date	198809
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : msy
State Reference	LA
Altitude	agl bound lower : 0 agl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : msy
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 2000
ASRS Report	94911
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Takeoff acceleration correspondingly rapid. Runway 28 used. Takeoff roll normal and all 3 airspeed indicators checked at 100 KIAS. At V1 on captain's side (captain's takeoff) the first officer's indicator read approximately 10 KTS low. Standby airspeed indicator checked and ground speed indicator checked. Due to rapid acceleration, takeoff continued using all captain's information. By this time it was obvious the first officer's airspeed indicator was unreliable (fluctuating airspeed, slow build up, intermittent flags, etc). At approximately 1000' first officer's static selector switched to alternate. No change and returned to normal. No changes. VHF/navigation switches all selected to both left, no change, then returned to normal, no change. At 3000' I queried ATC and their ground speed readout agreed with the information on my (captain's) side. I rechked en route and terminal WX reports and they indicated that the en route and terminal WX presented no obstacle to successful flight. The captain's standby static source-checked ok. Circuit breaker tests indicated that the #2 CADC appeared to be the culprit. I decided to continue the flight. Periodic checks with ATC confirmed that the captain's airspeed indicators were functioning properly. The flight to jan was routine and uneventful.

Original NASA ASRS Text

Title: DISCOVERED FO'S AIRSPEED UNRELIABLE AT V1. FLT CONTINUED TO DESTINATION.

Narrative: TKOF ACCELERATION CORRESPONDINGLY RAPID. RWY 28 USED. TKOF ROLL NORMAL AND ALL 3 AIRSPD INDICATORS CHKED AT 100 KIAS. AT V1 ON CAPT'S SIDE (CAPT'S TKOF) THE F/O'S INDICATOR READ APPROX 10 KTS LOW. STANDBY AIRSPD INDICATOR CHKED AND GND SPD INDICATOR CHKED. DUE TO RAPID ACCELERATION, TKOF CONTINUED USING ALL CAPT'S INFO. BY THIS TIME IT WAS OBVIOUS THE F/O'S AIRSPD INDICATOR WAS UNRELIABLE (FLUCTUATING AIRSPD, SLOW BUILD UP, INTERMITTENT FLAGS, ETC). AT APPROX 1000' F/O'S STATIC SELECTOR SWITCHED TO ALTERNATE. NO CHANGE AND RETURNED TO NORMAL. NO CHANGES. VHF/NAV SWITCHES ALL SELECTED TO BOTH LEFT, NO CHANGE, THEN RETURNED TO NORMAL, NO CHANGE. AT 3000' I QUERIED ATC AND THEIR GND SPD READOUT AGREED WITH THE INFO ON MY (CAPT'S) SIDE. I RECHKED ENRTE AND TERMINAL WX RPTS AND THEY INDICATED THAT THE ENRTE AND TERMINAL WX PRESENTED NO OBSTACLE TO SUCCESSFUL FLT. THE CAPT'S STANDBY STATIC SOURCE-CHKED OK. CB TESTS INDICATED THAT THE #2 CADC APPEARED TO BE THE CULPRIT. I DECIDED TO CONTINUE THE FLT. PERIODIC CHKS WITH ATC CONFIRMED THAT THE CAPT'S AIRSPD INDICATORS WERE FUNCTIONING PROPERLY. THE FLT TO JAN WAS ROUTINE AND UNEVENTFUL.

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.