Widebody transport takeoff below min RVR.

Attributes
ACN	195627
Time
Date	199111
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : jfk
State Reference	NY
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : atp
Experience	flight time last 90 days : 190 flight time total : 6700 flight time type : 400
ASRS Report	195627
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer pilot : instrument pilot : commercial
Experience	flight time last 90 days : 130 flight time total : 12000 flight time type : 130
ASRS Report	195292
Events
Anomaly	non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

As we approached the takeoff end of runway 4R at jfk the local controller told us to taxi into position and hold, shortly after he advised us that touchdown RVR for 4R was 0, rollout 1000 ft. I asked the captain twice 'how can we takeoff if the visibility is reported as 0?' he replied that the RVR was probably in error as he could see adequately down the runway (or something to that effect). I counted almost 4 sets of runway lights while we were in position which would have been the equivalent of approximately 750 ft, exceeding the min of 600 ft. We proceeded with the takeoff. After further discussion we realized that the deciding factor is the reported visibility and not what we could see. However, both of us still believe that what we did was not an unsafe operation, also there may be a problem with the TDZ transmissometers at 4R at jfk.

Original NASA ASRS Text

Title: WDB TKOF BELOW MIN RVR.

Narrative: AS WE APCHED THE TKOF END OF RWY 4R AT JFK THE LCL CTLR TOLD US TO TAXI INTO POS AND HOLD, SHORTLY AFTER HE ADVISED US THAT TOUCHDOWN RVR FOR 4R WAS 0, ROLLOUT 1000 FT. I ASKED THE CAPT TWICE 'HOW CAN WE TKOF IF THE VISIBILITY IS RPTED AS 0?' HE REPLIED THAT THE RVR WAS PROBABLY IN ERROR AS HE COULD SEE ADEQUATELY DOWN THE RWY (OR SOMETHING TO THAT EFFECT). I COUNTED ALMOST 4 SETS OF RWY LIGHTS WHILE WE WERE IN POS WHICH WOULD HAVE BEEN THE EQUIVALENT OF APPROX 750 FT, EXCEEDING THE MIN OF 600 FT. WE PROCEEDED WITH THE TKOF. AFTER FURTHER DISCUSSION WE REALIZED THAT THE DECIDING FACTOR IS THE RPTED VISIBILITY AND NOT WHAT WE COULD SEE. HOWEVER, BOTH OF US STILL BELIEVE THAT WHAT WE DID WAS NOT AN UNSAFE OP, ALSO THERE MAY BE A PROBLEM WITH THE TDZ TRANSMISSOMETERS AT 4R AT JFK.

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.