B757 crew had TCASII RA in muph class a airspace.

Attributes
ACN	459170
Time
Date	199912
Day	Wed
Local Time Of Day	1201 To 1800
Place
State Reference	FO
Altitude	msl bound lower : 27600 msl bound upper : 28000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute : other oceanic
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Route In Use	enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	459170
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
Events
Anomaly	conflict : airborne critical inflight encounter : weather non adherence : required legal separation
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb other other : 3
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were proceeding north and air carrier abc was proceeding south. We observed air carrier abc descending to FL290 on the 40 mi range in normal tilt. At about 20 mi, havana cleared air carrier abc to descend. As air carrier abc began to descend, we did likewise. TCASII almost immediately issued a descend RA. The command was 1500 FPM. Air carrier abc almost immediately stopped descent, and told havana they had received a TCASII RA to climb. At about FL276 we received a clear of conflict message. We confirmed the event with air carrier abc on frequency 130.55. There was a cirrus layer at FL290, so neither air carrier abc nor us had visual contact. TCASII saved a near miss or worse.

Original NASA ASRS Text

Title: B757 CREW HAD TCASII RA IN MUPH CLASS A AIRSPACE.

Narrative: WE WERE PROCEEDING N AND ACR ABC WAS PROCEEDING S. WE OBSERVED ACR ABC DSNDING TO FL290 ON THE 40 MI RANGE IN NORMAL TILT. AT ABOUT 20 MI, HAVANA CLRED ACR ABC TO DSND. AS ACR ABC BEGAN TO DSND, WE DID LIKEWISE. TCASII ALMOST IMMEDIATELY ISSUED A DSND RA. THE COMMAND WAS 1500 FPM. ACR ABC ALMOST IMMEDIATELY STOPPED DSCNT, AND TOLD HAVANA THEY HAD RECEIVED A TCASII RA TO CLB. AT ABOUT FL276 WE RECEIVED A CLR OF CONFLICT MESSAGE. WE CONFIRMED THE EVENT WITH ACR ABC ON FREQ 130.55. THERE WAS A CIRRUS LAYER AT FL290, SO NEITHER ACR ABC NOR US HAD VISUAL CONTACT. TCASII SAVED A NEAR MISS OR WORSE.

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.