Q400 Flight Crew reports being cleared out of their cruise altitude 150 NM from their destination. When the ZOA Controller is queried as to the reason for the early descent evasive answers are provided.
Synopsis
Q400 Flight Crew reports being cleared out of their cruise altitude 150 NM from their destination. When the ZOA Controller is queried as to the reason for the early descent evasive answers are provided.
Narrative
First descent from FL240 down to FL220 given when well east of RNO. Second descent from FL220 down to 16;000 FT given while near RNO. I asked ZOA Center if the descent was for traffic. ZOA Center replied; 'I'm not in the habit of explaining my instructions to pilots.' I replied that we were still a long ways from our destination and that flying at the lower altitudes increases our fuel burn but that we are descending from FL220 down to 16;000 FT. A few minutes later at approximately FL190 ZOA Center says he does not see us turning. I advise that we were not assigned a new heading. ZOA Controller says he told us to turn left 20 degrees. We comply. Both First Officer and Captain do not recall a new heading assignment being given nor did I read one back during the initial descent clearance. ZOA Center then tells us to expedite descent due to traffic. No traffic was ever pointed out to us and the only TCAS target displayed was at our 2:00 o'clock position; 18 miles and 1;400 FT below our altitude. ZOA Controller then advised us of 'possible pilot deviation' and gave us a phone number to call. I think the ATC Controller did not like me asking if the descent was for traffic I guess. I was just trying to be kept in the loop and be advised of any conflicting traffic in the area.
Second reporter narrative
ATC instructed us to descend to 16;000 and we were 150 NM from SJC. The Captain asked if the descent was do to traffic (after reading back the new altitude) because it seems far out from our destination (fuel cost). The Controller answered 'sort of' and stated he didn't like to be questioned about 'every clearance' he gives. I started descending at 1;200 FT per minute. The conversation between the Captain and the Controller continued but not smoothly. (Controller not answering or saying 'standby') Then the Controller stated 'you are not descending .... expedite your descend' . I increased my descent to 1;800 FT per minute. We never got a TA or RA nor noticed any traffic within 15 NM of us. When the Captain tried to inquirer about the conflict; the Controller stated that there was 'a possible conflict' and gave the pilot not flying a phone number. The rest of the flight went smoothly.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.