Speed deviation in departure procedure by B-767.

Attributes
ACN	271032
Time
Date	199405
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : jfk
State Reference	NY
Altitude	msl bound lower : 7000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : takeoff climbout : intermediate altitude climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 220 flight time total : 21000 flight time type : 3700
ASRS Report	271032
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical non adherence : far other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

On takeoff at jfk at the 80 KT speed check, both captain and first officer airspeed on the pfd's (primary flight displays) agreed. At V1/vr callout captain's airspeed was 15 KTS lower than first officer's. A slow rotation was accomplished and cleanup was done using the lower airspeed to insure a safe margin above stall. During the initial climb, after cleanup and trouble- shooting the problem, the airspeed exceeded the 250 KT below 10000 ft limit. A malfunctioning #1 air data computer (air data computer) was found to be the cause of the airspeed discrepancy. This was the first revenue flight after a major 'C' check had been performed on the aircraft at tulsa. Departure control was advised of the problem while it was occurring. On checking the maintenance performed on the aircraft after the incident, it was determined that a faulty captain's pitot system was inputing bad information to the #1 air data computer.

Original NASA ASRS Text

Title: SPD DEV IN DEP PROC BY B-767.

Narrative: ON TKOF AT JFK AT THE 80 KT SPD CHK, BOTH CAPT AND FO AIRSPD ON THE PFD'S (PRIMARY FLT DISPLAYS) AGREED. AT V1/VR CALLOUT CAPT'S AIRSPD WAS 15 KTS LOWER THAN FO'S. A SLOW ROTATION WAS ACCOMPLISHED AND CLEANUP WAS DONE USING THE LOWER AIRSPD TO INSURE A SAFE MARGIN ABOVE STALL. DURING THE INITIAL CLB, AFTER CLEANUP AND TROUBLE- SHOOTING THE PROB, THE AIRSPD EXCEEDED THE 250 KT BELOW 10000 FT LIMIT. A MALFUNCTIONING #1 ADC (AIR DATA COMPUTER) WAS FOUND TO BE THE CAUSE OF THE AIRSPD DISCREPANCY. THIS WAS THE FIRST REVENUE FLT AFTER A MAJOR 'C' CHK HAD BEEN PERFORMED ON THE ACFT AT TULSA. DEP CTL WAS ADVISED OF THE PROB WHILE IT WAS OCCURRING. ON CHKING THE MAINT PERFORMED ON THE ACFT AFTER THE INCIDENT, IT WAS DETERMINED THAT A FAULTY CAPT'S PITOT SYS WAS INPUTING BAD INFO TO THE #1 ADC.

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.