Narrative:

This flight was from bur-den with WX deviations all the way. Near mtj we were cleared direct to skeed intersection on the powder 3 arrival to den. This was 5-10 degrees left turn. The WX that direction did not look quite as good, but we were willing to try it. After a few mins on that course, it became apparent that this heading was unacceptable due to cell buildups in front of us and above us that we were not painting the WX cell on radar, but were clearly visible. After 3 or more unanswered calls to ZDV to request a right deviation, we had to turn about 25 degrees right to avoid WX. About the time we finished the turn, I got a hold of center and let him know we turned. He seemed incredulous and upset that we had turned without his permission, however we had no choice. We resumed course after 20-30 mi, but zigzagging all the way to den. 2 problems were at work here: due to limitations of communication system our requests went unheard for a critical length of time. (We were apparently stepped on by other xmissions. There seems to be a real breakdown in communications between controllers when it comes to the big picture. Quite often you will be advised by ATC to deviate one way, only to find out you've stepped into a mine field of WX in the next controller's sector down line (whether that be 100 mi or 1000 mi away). A similar problem exists with WX reroutes (swap routes, eg). By the time you get to the new route, the original route is clear and the new route now has WX problems. I would have to attribute this situation to the controller's lack of good WX data available and a lack of knowledge of the nature of thunderstorm life cycle and movement. We are often dependent on ATC for long range planning around WX, as airborne radar can be difficult to use beyond 100 mi or so, especially if there is little moisture present. Supplemental information from acn 443376: the captain told me to make a slight turn to the right to avoid the WX. About then, ATC called and asked us what we were doing, accusing us of turning into traffic (we saw him on TCASII approximately 15 mi away). ATC argued we were about to create an emergency situation, to which the captain said if we needed to declare an emergency we would, but we weren't going to fly 100 plus passenger and crew through a thunderstorm. This 'discussion' on the radio was not very professional, and tensions on both ends might have been alleviated if ATC had been more willing to work with us and having less of an accusatory attitude.

Google
 

Original NASA ASRS Text

Title: AN ACR FLC FLYING B737 TO DEN ENCOUNTERS WX ENRTE AND IS UNABLE TO COMPLY WITH ATC INSTRUCTIONS.

Narrative: THIS FLT WAS FROM BUR-DEN WITH WX DEVS ALL THE WAY. NEAR MTJ WE WERE CLRED DIRECT TO SKEED INTXN ON THE POWDER 3 ARR TO DEN. THIS WAS 5-10 DEGS L TURN. THE WX THAT DIRECTION DID NOT LOOK QUITE AS GOOD, BUT WE WERE WILLING TO TRY IT. AFTER A FEW MINS ON THAT COURSE, IT BECAME APPARENT THAT THIS HEADING WAS UNACCEPTABLE DUE TO CELL BUILDUPS IN FRONT OF US AND ABOVE US THAT WE WERE NOT PAINTING THE WX CELL ON RADAR, BUT WERE CLRLY VISIBLE. AFTER 3 OR MORE UNANSWERED CALLS TO ZDV TO REQUEST A R DEV, WE HAD TO TURN ABOUT 25 DEGS R TO AVOID WX. ABOUT THE TIME WE FINISHED THE TURN, I GOT A HOLD OF CTR AND LET HIM KNOW WE TURNED. HE SEEMED INCREDULOUS AND UPSET THAT WE HAD TURNED WITHOUT HIS PERMISSION, HOWEVER WE HAD NO CHOICE. WE RESUMED COURSE AFTER 20-30 MI, BUT ZIGZAGGING ALL THE WAY TO DEN. 2 PROBS WERE AT WORK HERE: DUE TO LIMITATIONS OF COM SYS OUR REQUESTS WENT UNHEARD FOR A CRITICAL LENGTH OF TIME. (WE WERE APPARENTLY STEPPED ON BY OTHER XMISSIONS. THERE SEEMS TO BE A REAL BREAKDOWN IN COMS BTWN CTLRS WHEN IT COMES TO THE BIG PICTURE. QUITE OFTEN YOU WILL BE ADVISED BY ATC TO DEVIATE ONE WAY, ONLY TO FIND OUT YOU'VE STEPPED INTO A MINE FIELD OF WX IN THE NEXT CTLR'S SECTOR DOWN LINE (WHETHER THAT BE 100 MI OR 1000 MI AWAY). A SIMILAR PROB EXISTS WITH WX REROUTES (SWAP ROUTES, EG). BY THE TIME YOU GET TO THE NEW RTE, THE ORIGINAL RTE IS CLR AND THE NEW RTE NOW HAS WX PROBS. I WOULD HAVE TO ATTRIBUTE THIS SIT TO THE CTLR'S LACK OF GOOD WX DATA AVAILABLE AND A LACK OF KNOWLEDGE OF THE NATURE OF TSTM LIFE CYCLE AND MOVEMENT. WE ARE OFTEN DEPENDENT ON ATC FOR LONG RANGE PLANNING AROUND WX, AS AIRBORNE RADAR CAN BE DIFFICULT TO USE BEYOND 100 MI OR SO, ESPECIALLY IF THERE IS LITTLE MOISTURE PRESENT. SUPPLEMENTAL INFO FROM ACN 443376: THE CAPT TOLD ME TO MAKE A SLIGHT TURN TO THE R TO AVOID THE WX. ABOUT THEN, ATC CALLED AND ASKED US WHAT WE WERE DOING, ACCUSING US OF TURNING INTO TFC (WE SAW HIM ON TCASII APPROX 15 MI AWAY). ATC ARGUED WE WERE ABOUT TO CREATE AN EMER SIT, TO WHICH THE CAPT SAID IF WE NEEDED TO DECLARE AN EMER WE WOULD, BUT WE WEREN'T GOING TO FLY 100 PLUS PAX AND CREW THROUGH A TSTM. THIS 'DISCUSSION' ON THE RADIO WAS NOT VERY PROFESSIONAL, AND TENSIONS ON BOTH ENDS MIGHT HAVE BEEN ALLEVIATED IF ATC HAD BEEN MORE WILLING TO WORK WITH US AND HAVING LESS OF AN ACCUSATORY ATTITUDE.

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.