Controller judgement of traffic spacing air carrier X same altitude assigned had less than standard ...

Attributes
ACN	225920
Time
Date	199211
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gve
State Reference	VA
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar instruction : instructor
Qualification	controller : radar
Experience	controller non radar : 8 controller radar : 7
ASRS Report	225920
Person 2
Affiliation	government : faa
Function	controller : radar instruction : trainee
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance flight crew : took evasive action other
Consequence	faa : investigated
Miss Distance	horizontal : 25800 vertical : 700
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X swbound at FL310 requesting FL350. Air carrier Y eastbound at FL330 required by ATC operating procedures to descend to FL290. I felt there was sufficient time to sway altitudes of both aircraft before crossing. Air carrier Y assigned FL290 and asked to give best rate through FL310. Air carrier X assigned FL330 and asked to climb at best rate. After a min, no change was noticed in air carrier X's mode C. Air carrier X assigned FL290 and told to expedite. Air carrier Y was told to stop descent at FL310. Air carrier X was actually above FL320 at this time. Air carrier X's lag in starting in climb and gap in updating of radar displayed mode C misled me to think air carrier X was still level at FL310. Situation was resolved by TCASII. Supplemental information from acn 226340: air carrier X had requested climb from FL310 to FL350. We were subsequently cleared to FL330 and started a climb to 330. Suddenly, a different controller (a male instead of female voice) asked us to expedite a descent to FL290, which we started to comply with by descending. Then we received TCASII alert of traffic 1-2 O'clock eastbound 1000 ft below us. The controller again asked us to expedite descent to FL290. After his last request, we received a TCASII RA to stop descent with the lights in the ivsi indicated a 2000 FPM climb, which we, without hesitation, complied with. The captain also commenced a left turn. I visually saw the intruder aircraft pass off of our right side in the clouds, at a TCASII altitude of 100-200 ft. We advised the controller we were following a TCASII RA and climbing through 32000 ft. He asked us to maintain FL330, which we did after the TCASII RA announced clear of conflict. The cause from our vantage point appeared to be lack of coordination with a controller change. We requested the altitude change with one controller (a female voice) and received the clearance to 330 from another voice (male). We also received the descent and expedite clearance from the new voice. Perhaps one didn't adequately brief the other as to the situation? Thank goodness for TCASII. The system worked in this situation.

Original NASA ASRS Text

Title: CTLR JUDGEMENT OF TFC SPACING ACR X SAME ALT ASSIGNED HAD LTSS FROM ACR Y. ACR X TCASII RA CLB EVASIVE ACTION TAKEN.

Narrative: ACR X SWBOUND AT FL310 REQUESTING FL350. ACR Y EBOUND AT FL330 REQUIRED BY ATC OPERATING PROCS TO DSND TO FL290. I FELT THERE WAS SUFFICIENT TIME TO SWAY ALTS OF BOTH ACFT BEFORE XING. ACR Y ASSIGNED FL290 AND ASKED TO GIVE BEST RATE THROUGH FL310. ACR X ASSIGNED FL330 AND ASKED TO CLB AT BEST RATE. AFTER A MIN, NO CHANGE WAS NOTICED IN ACR X'S MODE C. ACR X ASSIGNED FL290 AND TOLD TO EXPEDITE. ACR Y WAS TOLD TO STOP DSCNT AT FL310. ACR X WAS ACTUALLY ABOVE FL320 AT THIS TIME. ACR X'S LAG IN STARTING IN CLB AND GAP IN UPDATING OF RADAR DISPLAYED MODE C MISLED ME TO THINK ACR X WAS STILL LEVEL AT FL310. SITUATION WAS RESOLVED BY TCASII. SUPPLEMENTAL INFO FROM ACN 226340: ACR X HAD REQUESTED CLB FROM FL310 TO FL350. WE WERE SUBSEQUENTLY CLRED TO FL330 AND STARTED A CLB TO 330. SUDDENLY, A DIFFERENT CTLR (A MALE INSTEAD OF FEMALE VOICE) ASKED US TO EXPEDITE A DSCNT TO FL290, WHICH WE STARTED TO COMPLY WITH BY DSNDING. THEN WE RECEIVED TCASII ALERT OF TFC 1-2 O'CLOCK EBOUND 1000 FT BELOW US. THE CTLR AGAIN ASKED US TO EXPEDITE DSCNT TO FL290. AFTER HIS LAST REQUEST, WE RECEIVED A TCASII RA TO STOP DSCNT WITH THE LIGHTS IN THE IVSI INDICATED A 2000 FPM CLB, WHICH WE, WITHOUT HESITATION, COMPLIED WITH. THE CAPT ALSO COMMENCED A L TURN. I VISUALLY SAW THE INTRUDER ACFT PASS OFF OF OUR R SIDE IN THE CLOUDS, AT A TCASII ALT OF 100-200 FT. WE ADVISED THE CTLR WE WERE FOLLOWING A TCASII RA AND CLBING THROUGH 32000 FT. HE ASKED US TO MAINTAIN FL330, WHICH WE DID AFTER THE TCASII RA ANNOUNCED CLR OF CONFLICT. THE CAUSE FROM OUR VANTAGE POINT APPEARED TO BE LACK OF COORD WITH A CTLR CHANGE. WE REQUESTED THE ALT CHANGE WITH ONE CTLR (A FEMALE VOICE) AND RECEIVED THE CLRNC TO 330 FROM ANOTHER VOICE (MALE). WE ALSO RECEIVED THE DSCNT AND EXPEDITE CLRNC FROM THE NEW VOICE. PERHAPS ONE DIDN'T ADEQUATELY BRIEF THE OTHER AS TO THE SITUATION? THANK GOODNESS FOR TCASII. THE SYS WORKED IN THIS SITUATION.

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.

Controller judgement of traffic spacing air carrier X same altitude assigned had less than standard separation from air carrier Y. Air carrier X TCASII RA climb evasive action taken.