Flight crew questions takeoff when only one RVR reported.

Attributes
ACN	100791
Time
Date	198812
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : iah
State Reference	TX
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : takeoff ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 120 flight time total : 12000 flight time type : 6000
ASRS Report	100791
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 120 flight time total : 4000 flight time type : 400
ASRS Report	100698
Events
Anomaly	other anomaly other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were ready for takeoff at iah, the WX was reported 3/8 mi visibility and RVR for departure runway was 1400'. The controller asked if we could takeoff with this visibility; we assumed both RVR readouts were 1400' since nothing to the contrary was said. We made a normal takeoff with no problems. My concern is are we to expect two (or three) RVR readouts given only if they are different and assume they are the same if only one is given? Callback conversation with reporter revealed following information. Reporter advised he has just received an update of the company operations specifications with some clarification of the far governing takeoff RVR. Advised analyst was unable to find any specific reference to the second reading on mid or rollout RVR if not reported but when he was active it was the policy if all RVR were known to be operating and mid or rollout was not reported it was because they were at least equal to or better than T/D RVR. After they departed all other aircraft waiting takeoff departed, like someone needed to break the ice.

Original NASA ASRS Text

Title: FLT CREW QUESTIONS TKOF WHEN ONLY ONE RVR REPORTED.

Narrative: WE WERE READY FOR TKOF AT IAH, THE WX WAS RPTED 3/8 MI VISIBILITY AND RVR FOR DEP RWY WAS 1400'. THE CTLR ASKED IF WE COULD TKOF WITH THIS VISIBILITY; WE ASSUMED BOTH RVR READOUTS WERE 1400' SINCE NOTHING TO THE CONTRARY WAS SAID. WE MADE A NORMAL TKOF WITH NO PROBS. MY CONCERN IS ARE WE TO EXPECT TWO (OR THREE) RVR READOUTS GIVEN ONLY IF THEY ARE DIFFERENT AND ASSUME THEY ARE THE SAME IF ONLY ONE IS GIVEN? CALLBACK CONVERSATION WITH RPTR REVEALED FOLLOWING INFO. RPTR ADVISED HE HAS JUST RECEIVED AN UPDATE OF THE COMPANY OPERATIONS SPECIFICATIONS WITH SOME CLARIFICATION OF THE FAR GOVERNING TKOF RVR. ADVISED ANALYST WAS UNABLE TO FIND ANY SPECIFIC REFERENCE TO THE SECOND READING ON MID OR ROLLOUT RVR IF NOT RPTED BUT WHEN HE WAS ACTIVE IT WAS THE POLICY IF ALL RVR WERE KNOWN TO BE OPERATING AND MID OR ROLLOUT WAS NOT RPTED IT WAS BECAUSE THEY WERE AT LEAST EQUAL TO OR BETTER THAN T/D RVR. AFTER THEY DEPARTED ALL OTHER ACFT WAITING TKOF DEPARTED, LIKE SOMEONE NEEDED TO BREAK THE ICE.

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.