Narrative:

This event involved myself; first officer; another air carrier's crew; and ZZZ tower. It occurred on the morning of nov/xa/08. Ourselves and another flight were the first aircraft to depart that morning. It had been snowing since approximately XA00 that morning. The runway was freshly plowed; brushed; and to our understanding had .25 inches of snow contaminant. I had the dispatcher rework our takeoff performance from level 1 to level 2. After a lengthy delay awaiting deicing; due to the fact that our deice truck was broken and we had to use another air carrier's equipment; we taxied out behind them for runway 2. Txwys were covered in snow; but plowed; and braking action was good. As we taxied out; tower informed us that the initial mu readings for runway 2 were 19 touchdown; 23 mid; and 19 rollout; but they would have new readings shortly. As we approached the end of the runway 2; #2 behind the other air carrier; tower informed us that new mu readings were 19 touchdown; 23 mid; and 33 rollout. First officer and myself discussed the improving trend on the rollout mu; where maximum braking would be required during an aborted takeoff; not the 19 reading at touchdown. Realizing that braking action per our poh starts to deteriorate below mu 40; but was probably fair to poor. As there is no correlation between friction reports and braking action reports; this was our best guess. Also; we discussed the need for extra vigilance between 80 KTS and our V1 should any problems arise due to the conditions. After the new readings were issued; the other flight refused to take off. We accepted the takeoff clearance and other aircraft was taxied down the runway to the first turnoff to return for takeoff. While the other flight was taxiing down the runway; the crew keyed the microphone and asked to speak with us on the tower frequency. I acknowledged by saying 'go ahead.' the other air carrier crew asked us if we were approved to take off with braking action 'nil.' I responded by saying that we understood the rollout mu to be 33. He responded by saying we understand 19; and then he replied something like 'ok;' as in disbelief. We thought he might be confused since there is no correlation between friction reports and braking action reports; and that 19 was touchdown and not rollout. The takeoff was uneventful; and runway markings were clearly visible on the runway. The event occurred due to atmospheric conditions and confusion between the other crew and ourselves. And our belief that the other crew was incorrectly identing the current operational conditions. We were not on the frequency the entire time; so we may have missed conversations between them and the tower. I feel like our guidance is vague concerning criteria to takeoff in these conditions. My understanding is -- if braking action is poor; it is advised that the takeoff be delayed and takeoff is prohibited if wet snow is .59 inches; or 3.00 inches of dry snow. Without another PIREP on braking action; we had to use previous experience; aircraft weight; wind conditions (which were directly down the runway) and our interpolation of the mu readings. I would like to be notified if we have better criteria for making these decisions as I have looked extensively through our manuals and can find nothing more.

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Original NASA ASRS Text

Title: A CRJ-700 CREW QUESTIONS THE VAGUENESS OF MU RUNWAY FRICTION REPORTS. A TAKEOFF WITH MU READINGS OF 19 TOUCH DOWN; 23 MID; AND 33 ROLLOUT WAS CONDUCTED. THE CREW LATER INQUIRED ABOUT BETTER TAKEOFF GUIDANCE WITH REDUCED FRICTION CONDITIONS.

Narrative: THIS EVENT INVOLVED MYSELF; FO; ANOTHER ACR'S CREW; AND ZZZ TWR. IT OCCURRED ON THE MORNING OF NOV/XA/08. OURSELVES AND ANOTHER FLT WERE THE FIRST ACFT TO DEPART THAT MORNING. IT HAD BEEN SNOWING SINCE APPROX XA00 THAT MORNING. THE RWY WAS FRESHLY PLOWED; BRUSHED; AND TO OUR UNDERSTANDING HAD .25 INCHES OF SNOW CONTAMINANT. I HAD THE DISPATCHER REWORK OUR TKOF PERFORMANCE FROM LEVEL 1 TO LEVEL 2. AFTER A LENGTHY DELAY AWAITING DEICING; DUE TO THE FACT THAT OUR DEICE TRUCK WAS BROKEN AND WE HAD TO USE ANOTHER ACR'S EQUIP; WE TAXIED OUT BEHIND THEM FOR RWY 2. TXWYS WERE COVERED IN SNOW; BUT PLOWED; AND BRAKING ACTION WAS GOOD. AS WE TAXIED OUT; TWR INFORMED US THAT THE INITIAL MU READINGS FOR RWY 2 WERE 19 TOUCHDOWN; 23 MID; AND 19 ROLLOUT; BUT THEY WOULD HAVE NEW READINGS SHORTLY. AS WE APCHED THE END OF THE RWY 2; #2 BEHIND THE OTHER ACR; TWR INFORMED US THAT NEW MU READINGS WERE 19 TOUCHDOWN; 23 MID; AND 33 ROLLOUT. FO AND MYSELF DISCUSSED THE IMPROVING TREND ON THE ROLLOUT MU; WHERE MAX BRAKING WOULD BE REQUIRED DURING AN ABORTED TKOF; NOT THE 19 READING AT TOUCHDOWN. REALIZING THAT BRAKING ACTION PER OUR POH STARTS TO DETERIORATE BELOW MU 40; BUT WAS PROBABLY FAIR TO POOR. AS THERE IS NO CORRELATION BTWN FRICTION RPTS AND BRAKING ACTION RPTS; THIS WAS OUR BEST GUESS. ALSO; WE DISCUSSED THE NEED FOR EXTRA VIGILANCE BTWN 80 KTS AND OUR V1 SHOULD ANY PROBS ARISE DUE TO THE CONDITIONS. AFTER THE NEW READINGS WERE ISSUED; THE OTHER FLT REFUSED TO TAKE OFF. WE ACCEPTED THE TKOF CLRNC AND OTHER ACFT WAS TAXIED DOWN THE RWY TO THE FIRST TURNOFF TO RETURN FOR TKOF. WHILE THE OTHER FLT WAS TAXIING DOWN THE RWY; THE CREW KEYED THE MIKE AND ASKED TO SPEAK WITH US ON THE TWR FREQ. I ACKNOWLEDGED BY SAYING 'GO AHEAD.' THE OTHER ACR CREW ASKED US IF WE WERE APPROVED TO TAKE OFF WITH BRAKING ACTION 'NIL.' I RESPONDED BY SAYING THAT WE UNDERSTOOD THE ROLLOUT MU TO BE 33. HE RESPONDED BY SAYING WE UNDERSTAND 19; AND THEN HE REPLIED SOMETHING LIKE 'OK;' AS IN DISBELIEF. WE THOUGHT HE MIGHT BE CONFUSED SINCE THERE IS NO CORRELATION BTWN FRICTION RPTS AND BRAKING ACTION RPTS; AND THAT 19 WAS TOUCHDOWN AND NOT ROLLOUT. THE TKOF WAS UNEVENTFUL; AND RWY MARKINGS WERE CLEARLY VISIBLE ON THE RWY. THE EVENT OCCURRED DUE TO ATMOSPHERIC CONDITIONS AND CONFUSION BTWN THE OTHER CREW AND OURSELVES. AND OUR BELIEF THAT THE OTHER CREW WAS INCORRECTLY IDENTING THE CURRENT OPERATIONAL CONDITIONS. WE WERE NOT ON THE FREQ THE ENTIRE TIME; SO WE MAY HAVE MISSED CONVERSATIONS BTWN THEM AND THE TWR. I FEEL LIKE OUR GUIDANCE IS VAGUE CONCERNING CRITERIA TO TKOF IN THESE CONDITIONS. MY UNDERSTANDING IS -- IF BRAKING ACTION IS POOR; IT IS ADVISED THAT THE TKOF BE DELAYED AND TKOF IS PROHIBITED IF WET SNOW IS .59 INCHES; OR 3.00 INCHES OF DRY SNOW. WITHOUT ANOTHER PIREP ON BRAKING ACTION; WE HAD TO USE PREVIOUS EXPERIENCE; ACFT WT; WIND CONDITIONS (WHICH WERE DIRECTLY DOWN THE RWY) AND OUR INTERPOLATION OF THE MU READINGS. I WOULD LIKE TO BE NOTIFIED IF WE HAVE BETTER CRITERIA FOR MAKING THESE DECISIONS AS I HAVE LOOKED EXTENSIVELY THROUGH OUR MANUALS AND CAN FIND NOTHING MORE.

Data retrieved from NASA's ASRS site as of May 2009 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.