Narrative:

Assigned FL370; northbound on airway A590 about 180 NM south of gurag intersection. The captain was pilot flying. We received a TCAS warning; 'traffic; traffic; descend; descend.' the traffic on TCAS was at our 0900 [o'clock] position (aircraft left) about 20 miles; at same altitude. I visually confirmed conflicting traffic in sight (captain did not see traffic). Captain did TCAS resolution maneuver; and descended. I monitored the descent on TCAS; and observed the conflicting traffic climbing; both on TCAS; and visually. We cleared traffic by 2;200 feet (per TCAS). We climbed back up to FL370; and when level; observed that conflicting traffic (now behind; and to our right) had also returned to FL370.we established contact with conflicting traffic on frequency 123.45. It was a KC135 tanker and he advised his cleared altitude was also FL370. Contacted manila radio on HF 8903 to pass along to manila control of our resolution advisory maneuver; and to also confirm our cleared altitude. Manila radio replied our confirmed altitude was FL370.

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Original NASA ASRS Text

Title: B747 First Officer experiences a TCAS RA at FL370 on A590 north bound with a KC135 converging from the west at the same altitude. Evasive action is taken by both aircraft. Both aircraft were apparently at their correct altitude as assigned by Manila Control.

Narrative: Assigned FL370; northbound on Airway A590 about 180 NM south of GURAG Intersection. The Captain was pilot flying. We received a TCAS warning; 'TRAFFIC; TRAFFIC; DESCEND; DESCEND.' The traffic on TCAS was at our 0900 [o'clock] position (aircraft left) about 20 miles; at same altitude. I visually confirmed conflicting traffic in sight (Captain did not see traffic). Captain did TCAS resolution maneuver; and descended. I monitored the descent on TCAS; and observed the conflicting traffic climbing; both on TCAS; and visually. We cleared traffic by 2;200 feet (per TCAS). We climbed back up to FL370; and when level; observed that conflicting traffic (now behind; and to our right) had also returned to FL370.We established contact with conflicting traffic on frequency 123.45. It was a KC135 tanker and he advised his cleared altitude was also FL370. Contacted Manila Radio on HF 8903 to pass along to Manila Control of our resolution advisory maneuver; and to also confirm our cleared altitude. Manila Radio replied our confirmed altitude was FL370.

Data retrieved from NASA's ASRS site 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.