Less than standard separation occurred between two aircraft on converging courses.

Attributes
ACN	169371
Time
Date	199101
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sby
State Reference	MD
Altitude	msl bound lower : 15000 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : bna
Operator	common carrier : air carrier
Make Model Name	Medium Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Fighter
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 : 180 flight time total : 13000 flight time type : 1600
ASRS Report	169371
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 1800
ASRS Report	169373
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 1000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

On flight from phl to mco about 30 mi north of salisbury, we were cleared from 15000' to 17000'. We were using the VNAV feature of the autoplt. As we climbed through about 16300' with the 'altitude acq' feature already leveling the aircraft for our 17000' level off. Dca center called and said 'stop your climb at 16000'.' I immediately snapped off the autoplt and autothrottle, pulled the throttles way back and eased the aircraft over, but, the aircraft still got to about 16500' before it started down. During this maneuver, we told the controller that we were already well through 16000', and he then said, ok, go on up to 17000'. At that point I spotted a military fighter jet C about my 9 O'clock position and about 5 mi away. The problem was he appeared to be on a collision course for us and if we climbed back up to 17000'. It looked as if it would have been extremely hazardous for us. So, I elected to stay visly below with the power back prepared to dive, if that became necessary. The fighter turned out to be an fgt. It spotted us at some point and started a hard right turn to pass above and behind us, which we did. As we got a good look, we saw the slanted twin tails of the fgt. At some point after he had cleared us back to 17000' while we were staying down, the controller also cleared us to FL200 with an expedite through FL180. This was impossible for us to do also with any safety at all. Asking us to stop at 16000' after we had already passed it tells me that apparently the controller's information was not keeping up with real time happenings. Also, even after the fgt had passed behind us and was well off to our right rear the controller asked if we had the traffic at 9 O'clock at least 5-10 seconds after he had actually been at our 9 O'clock. Also I suppose the fgt speed could have been maybe twice ours. It's possible that he didn't descend rapidly enough to allow for the required sep, thus creating the crisis.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION OCCURRED BETWEEN TWO ACFT ON CONVERGING COURSES.

Narrative: ON FLT FROM PHL TO MCO ABOUT 30 MI N OF SALISBURY, WE WERE CLRED FROM 15000' TO 17000'. WE WERE USING THE VNAV FEATURE OF THE AUTOPLT. AS WE CLBED THROUGH ABOUT 16300' WITH THE 'ALT ACQ' FEATURE ALREADY LEVELING THE ACFT FOR OUR 17000' LEVEL OFF. DCA CTR CALLED AND SAID 'STOP YOUR CLB AT 16000'.' I IMMEDIATELY SNAPPED OFF THE AUTOPLT AND AUTOTHROTTLE, PULLED THE THROTTLES WAY BACK AND EASED THE ACFT OVER, BUT, THE ACFT STILL GOT TO ABOUT 16500' BEFORE IT STARTED DOWN. DURING THIS MANEUVER, WE TOLD THE CTLR THAT WE WERE ALREADY WELL THROUGH 16000', AND HE THEN SAID, OK, GO ON UP TO 17000'. AT THAT POINT I SPOTTED A MIL FIGHTER JET C ABOUT MY 9 O'CLOCK POS AND ABOUT 5 MI AWAY. THE PROB WAS HE APPEARED TO BE ON A COLLISION COURSE FOR US AND IF WE CLBED BACK UP TO 17000'. IT LOOKED AS IF IT WOULD HAVE BEEN EXTREMELY HAZARDOUS FOR US. SO, I ELECTED TO STAY VISLY BELOW WITH THE PWR BACK PREPARED TO DIVE, IF THAT BECAME NECESSARY. THE FIGHTER TURNED OUT TO BE AN FGT. IT SPOTTED US AT SOME POINT AND STARTED A HARD R TURN TO PASS ABOVE AND BEHIND US, WHICH WE DID. AS WE GOT A GOOD LOOK, WE SAW THE SLANTED TWIN TAILS OF THE FGT. AT SOME POINT AFTER HE HAD CLRED US BACK TO 17000' WHILE WE WERE STAYING DOWN, THE CTLR ALSO CLRED US TO FL200 WITH AN EXPEDITE THROUGH FL180. THIS WAS IMPOSSIBLE FOR US TO DO ALSO WITH ANY SAFETY AT ALL. ASKING US TO STOP AT 16000' AFTER WE HAD ALREADY PASSED IT TELLS ME THAT APPARENTLY THE CTLR'S INFO WAS NOT KEEPING UP WITH REAL TIME HAPPENINGS. ALSO, EVEN AFTER THE FGT HAD PASSED BEHIND US AND WAS WELL OFF TO OUR R REAR THE CTLR ASKED IF WE HAD THE TFC AT 9 O'CLOCK AT LEAST 5-10 SECS AFTER HE HAD ACTUALLY BEEN AT OUR 9 O'CLOCK. ALSO I SUPPOSE THE FGT SPD COULD HAVE BEEN MAYBE TWICE OURS. IT'S POSSIBLE THAT HE DIDN'T DSND RAPIDLY ENOUGH TO ALLOW FOR THE REQUIRED SEP, THUS CREATING THE CRISIS.

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.