Air carrier widebody transport takeoff in WX reported below airport takeoff minimums.

Attributes
ACN	103335
Time
Date	198901
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sea
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sea
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000 flight time type : 3000
ASRS Report	103335
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : far
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:

Takeoff RVR had gone down to 400'. We waited for takeoff RVR to increase to 600. Regulations read 3 RVR must read 600'. However if 1 RVR is inoperative you can takeoff as long as approach and rollout read 600'. All 3 were working at the time, though we felt a takeoff was possible because approach and rollout read 600'. This regulation is very ambiguous. Upon reading the regulation again, we felt we should have waited, although we were within limits

Original NASA ASRS Text

Title: ACR WDB TKOF IN WX REPORTED BELOW ARPT TKOF MINIMUMS.

Narrative: TKOF RVR HAD GONE DOWN TO 400'. WE WAITED FOR TKOF RVR TO INCREASE TO 600. REGS READ 3 RVR MUST READ 600'. HOWEVER IF 1 RVR IS INOP YOU CAN TKOF AS LONG AS APCH AND ROLLOUT READ 600'. ALL 3 WERE WORKING AT THE TIME, THOUGH WE FELT A TKOF WAS POSSIBLE BECAUSE APCH AND ROLLOUT READ 600'. THIS REG IS VERY AMBIGUOUS. UPON READING THE REG AGAIN, WE FELT WE SHOULD HAVE WAITED, ALTHOUGH WE WERE WITHIN LIMITS

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.