Narrative:

VMC in cruise at FL370; we received a TCAS RA to climb. No caution [TA] preceded event. TCAS showed a target immediately below our aircraft at 36;900 ft with an up arrow indicating aircraft was climbing. We followed TCAS commands to avoid aircraft and climbed and notified ATC. We received one 'increase climb' call out during the event. The target stayed 100 ft below our aircraft until 37;900 ft and then disappeared. We leveled off at 38;500 ft and asked ATC if they had any targets in our area. Cleveland center did not show any targets and we descended back down to FL370. Event took about 10-15 seconds. Maintenance control was advised and a mechanic briefed upon arrival.

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Original NASA ASRS Text

Title: A B757-200 flight crew followed TCAS RA 'climb' commands from their cruise at FL370 through FL385 where the 'traffic' disappeared.

Narrative: VMC in cruise at FL370; we received a TCAS RA to climb. No caution [TA] preceded event. TCAS showed a target immediately below our aircraft at 36;900 FT with an up arrow indicating aircraft was climbing. We followed TCAS commands to avoid aircraft and climbed and notified ATC. We received one 'increase climb' call out during the event. The target stayed 100 FT below our aircraft until 37;900 FT and then disappeared. We leveled off at 38;500 FT and asked ATC if they had any targets in our area. Cleveland Center did not show any targets and we descended back down to FL370. Event took about 10-15 seconds. Maintenance Control was advised and a Mechanic briefed upon arrival.

Data retrieved from NASA's ASRS site as of April 2012 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.