Medium large transport has TCASII RA for traffic opposite direction same altitude.

Attributes
ACN	257729
Time
Date	199311
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ekn
State Reference	WV
Altitude	msl bound lower : 24000 msl bound upper : 25000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 7500 flight time type : 1500
ASRS Report	257729
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 2500 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were cruising at FL250 and working with ZDC on frequency 134.62 en route rdu-pit. Washington was apparently late in handing us off to washington on 133.02. As we switched over to 133.02 we heard the controller asking us if we were on the frequency. We responded 'yes, they just switched us over and we are checking in at FL250.' he responded, 'roger,' and nothing more. After 5 mins or so, received a 'traffic' warning on the TCASII. After checking TCASII we noticed, 11 O'clock converging traffic at our same altitude. Still no response from ATC. Inside of 10 mi, received an RA warning on TCASII followed shortly by a 'descend' command. At about the same time, ZDC asked us if we were at FL240 -- we responded 'negative,' level at FL250 assigned.' we continued initiating a 2500-3000 FPM descent to FL240 as ATC then started issuing climb instructions to the converging traffic and descend instructions to us. He was talking so fast he could hardly spit the words out! As we leveled at FL240, we then saw the traffic pass overhead. The whole event took 15-20 seconds -- no more. I then requested an explanation from ATC -- who said that he issued us a clearance to FL240, and that a company aircraft must have answered for us. We responded that we checked in at FL250, and never received a clearance to FL240, nor did we ever respond to any such clearance. He then responded, 'roger, his mistake.' he then switched us to another frequency. Had it not been for TCASII this could have evolved into a very serious situation. It alerted us to the potentially dangerous traffic.

Original NASA ASRS Text

Title: MLG HAS TCASII RA FOR TFC OPPOSITE DIRECTION SAME ALT.

Narrative: WE WERE CRUISING AT FL250 AND WORKING WITH ZDC ON FREQ 134.62 ENRTE RDU-PIT. WASHINGTON WAS APPARENTLY LATE IN HANDING US OFF TO WASHINGTON ON 133.02. AS WE SWITCHED OVER TO 133.02 WE HEARD THE CTLR ASKING US IF WE WERE ON THE FREQ. WE RESPONDED 'YES, THEY JUST SWITCHED US OVER AND WE ARE CHKING IN AT FL250.' HE RESPONDED, 'ROGER,' AND NOTHING MORE. AFTER 5 MINS OR SO, RECEIVED A 'TFC' WARNING ON THE TCASII. AFTER CHKING TCASII WE NOTICED, 11 O'CLOCK CONVERGING TFC AT OUR SAME ALT. STILL NO RESPONSE FROM ATC. INSIDE OF 10 MI, RECEIVED AN RA WARNING ON TCASII FOLLOWED SHORTLY BY A 'DSND' COMMAND. AT ABOUT THE SAME TIME, ZDC ASKED US IF WE WERE AT FL240 -- WE RESPONDED 'NEGATIVE,' LEVEL AT FL250 ASSIGNED.' WE CONTINUED INITIATING A 2500-3000 FPM DSCNT TO FL240 AS ATC THEN STARTED ISSUING CLB INSTRUCTIONS TO THE CONVERGING TFC AND DSND INSTRUCTIONS TO US. HE WAS TALKING SO FAST HE COULD HARDLY SPIT THE WORDS OUT! AS WE LEVELED AT FL240, WE THEN SAW THE TFC PASS OVERHEAD. THE WHOLE EVENT TOOK 15-20 SECONDS -- NO MORE. I THEN REQUESTED AN EXPLANATION FROM ATC -- WHO SAID THAT HE ISSUED US A CLRNC TO FL240, AND THAT A COMPANY ACFT MUST HAVE ANSWERED FOR US. WE RESPONDED THAT WE CHKED IN AT FL250, AND NEVER RECEIVED A CLRNC TO FL240, NOR DID WE EVER RESPOND TO ANY SUCH CLRNC. HE THEN RESPONDED, 'ROGER, HIS MISTAKE.' HE THEN SWITCHED US TO ANOTHER FREQ. HAD IT NOT BEEN FOR TCASII THIS COULD HAVE EVOLVED INTO A VERY SERIOUS SIT. IT ALERTED US TO THE POTENTIALLY DANGEROUS TFC.

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.