Loss of separation between 2 same direction aircraft in descent. Pilot or operational error implied.

Attributes
ACN	140492
Time
Date	199003
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : dpk
State Reference	NY
Altitude	msl bound lower : 15000 msl bound upper : 19000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny artcc : zbw
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent 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 : 200 flight time total : 14500 flight time type : 1500
ASRS Report	140492
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 80 flight time total : 8500 flight time type : 500
ASRS Report	140406
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : clearance other anomaly other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 28800 vertical : 300
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation Operational Error other

Narrative:

I was the PF a widebody transport. We were cleared to descend to 15000'. Mins later, after a handoff from ZNY to ZBW, the controller asked, 'what altitude are you cleared to.' the copilot replied 18000', then corrected himself at said 15000'. We were at 18300' at this time. We were given a turn to 090 degree heading and told to climb back to 19000', but that was quickly changed to 18500'. After about 1 min we were again cleared to 15000'. I think this was a case of controller inexperience. He allowed our aircraft to overrun the aircraft ahead. We were flying at 320 KTS, told to slow to 250 KTS. This takes several mi--an experienced controller would know how many. Supplemental information from acn 140406: captain was slowing aircraft with speed brakes in descent to 15000'. My headset and vol control were turned up sufficiently loud. I do not feel miscom was part of the problem. 2 hours after landing in a phone call to ZBW, they said it appeared to be a computer problem. He said sep was 4.8 mi. He did not seem concerned with any altitude problem.

Original NASA ASRS Text

Title: LOSS OF SEPARATION BETWEEN 2 SAME DIRECTION ACFT IN DESCENT. PLT OR OPERATIONAL ERROR IMPLIED.

Narrative: I WAS THE PF A WDB. WE WERE CLRED TO DSND TO 15000'. MINS LATER, AFTER A HDOF FROM ZNY TO ZBW, THE CTLR ASKED, 'WHAT ALT ARE YOU CLRED TO.' THE COPLT REPLIED 18000', THEN CORRECTED HIMSELF AT SAID 15000'. WE WERE AT 18300' AT THIS TIME. WE WERE GIVEN A TURN TO 090 DEG HDG AND TOLD TO CLB BACK TO 19000', BUT THAT WAS QUICKLY CHANGED TO 18500'. AFTER ABOUT 1 MIN WE WERE AGAIN CLRED TO 15000'. I THINK THIS WAS A CASE OF CTLR INEXPERIENCE. HE ALLOWED OUR ACFT TO OVERRUN THE ACFT AHEAD. WE WERE FLYING AT 320 KTS, TOLD TO SLOW TO 250 KTS. THIS TAKES SEVERAL MI--AN EXPERIENCED CTLR WOULD KNOW HOW MANY. SUPPLEMENTAL INFO FROM ACN 140406: CAPT WAS SLOWING ACFT WITH SPEED BRAKES IN DSCNT TO 15000'. MY HEADSET AND VOL CTL WERE TURNED UP SUFFICIENTLY LOUD. I DO NOT FEEL MISCOM WAS PART OF THE PROB. 2 HRS AFTER LNDG IN A PHONE CALL TO ZBW, THEY SAID IT APPEARED TO BE A COMPUTER PROB. HE SAID SEP WAS 4.8 MI. HE DID NOT SEEM CONCERNED WITH ANY ALT PROB.

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.