Near midair collision. Foreign airspace aircraft cleared through another's altitude.

Attributes
ACN	321173
Time
Date	199511
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : vyyy
State Reference	FO
Altitude	msl bound lower : 36500 msl bound upper : 39000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : vyyy
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 13500
ASRS Report	321174
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : nmac non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Miss Distance	horizontal : 600 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

In contact with yangon control at FL350. Requested FL390. Checked dwi and cleared to FL390 by yangon on 134.2. At approximately XXXX made visual contact with air carrier X. He was level at FL370 eastbound, we were climbing out of FL365 at about 1000 ft. He was to our right. We continued the climb without making any maneuver maintaining visual separation. Air carrier X mentioned that he had picked us out on his TCASII and that he was filing a near miss. We had not heard air carrier X on yangon 134.2 frequency since we had only been on the frequency for a few mins and he had not made a report. It appears he did not hear us given a clearance which climbed us through his level. He was as surprised as we were by this sudden encounter. I can only surmise that the clearance given to us by yangon control was a plain and simple mistake. I can see no other possible factors. I have not flown this sector more than half a dozen times, but this section of airway is always busy with aircraft climbing out of bangkok and aircraft wanting to start their descent into bangkok. It would certainly be safer I feel, if 1 control center covered say 250 NM from bangkok, we would at least have heard air carrier X. As it is, the frequency changeover occurs at a critical geographical position. Incidentally, he had contacted yangon center before entering myanmar airspace, although I don't believe this has any particular relevance.

Original NASA ASRS Text

Title: NMAC. FOREIGN AIRSPACE ACFT CLRED THROUGH ANOTHER'S ALT.

Narrative: IN CONTACT WITH YANGON CTL AT FL350. REQUESTED FL390. CHKED DWI AND CLRED TO FL390 BY YANGON ON 134.2. AT APPROX XXXX MADE VISUAL CONTACT WITH ACR X. HE WAS LEVEL AT FL370 EBOUND, WE WERE CLBING OUT OF FL365 AT ABOUT 1000 FT. HE WAS TO OUR R. WE CONTINUED THE CLB WITHOUT MAKING ANY MANEUVER MAINTAINING VISUAL SEPARATION. ACR X MENTIONED THAT HE HAD PICKED US OUT ON HIS TCASII AND THAT HE WAS FILING A NEAR MISS. WE HAD NOT HEARD ACR X ON YANGON 134.2 FREQ SINCE WE HAD ONLY BEEN ON THE FREQ FOR A FEW MINS AND HE HAD NOT MADE A RPT. IT APPEARS HE DID NOT HEAR US GIVEN A CLRNC WHICH CLBED US THROUGH HIS LEVEL. HE WAS AS SURPRISED AS WE WERE BY THIS SUDDEN ENCOUNTER. I CAN ONLY SURMISE THAT THE CLRNC GIVEN TO US BY YANGON CTL WAS A PLAIN AND SIMPLE MISTAKE. I CAN SEE NO OTHER POSSIBLE FACTORS. I HAVE NOT FLOWN THIS SECTOR MORE THAN HALF A DOZEN TIMES, BUT THIS SECTION OF AIRWAY IS ALWAYS BUSY WITH ACFT CLBING OUT OF BANGKOK AND ACFT WANTING TO START THEIR DSCNT INTO BANGKOK. IT WOULD CERTAINLY BE SAFER I FEEL, IF 1 CTL CTR COVERED SAY 250 NM FROM BANGKOK, WE WOULD AT LEAST HAVE HEARD ACR X. AS IT IS, THE FREQ CHANGEOVER OCCURS AT A CRITICAL GEOGRAPHICAL POS. INCIDENTALLY, HE HAD CONTACTED YANGON CTR BEFORE ENTERING MYANMAR AIRSPACE, ALTHOUGH I DON'T BELIEVE THIS HAS ANY PARTICULAR RELEVANCE.

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.