An air carrier large transport got caught spacing itself with TCASII in the landing pattern.

Attributes
ACN	256917
Time
Date	199311
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ewr
State Reference	NJ
Altitude	msl bound lower : 1500 msl bound upper : 1500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tower : ewr
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 180 flight time total : 14000 flight time type : 8000
ASRS Report	256917
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	non adherence : clearance other anomaly other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Was flying approach at 17 KTS assigned. Was following aircraft about 4 mi ahead. Watching aircraft on TCASII noticed we were overtaking. Started slowing 3 mi before OM to maintain separation. Tower asked our airspeed. When we said we started to slow, we were reminded we were to hold 170 KTS to marker. Looking at this situation, we should have queried tower as to our separation opposed to trying to maintain our own with TCASII.

Original NASA ASRS Text

Title: AN ACR LGT GOT CAUGHT SPACING ITSELF WITH TCASII IN THE LNDG PATTERN.

Narrative: WAS FLYING APCH AT 17 KTS ASSIGNED. WAS FOLLOWING ACFT ABOUT 4 MI AHEAD. WATCHING ACFT ON TCASII NOTICED WE WERE OVERTAKING. STARTED SLOWING 3 MI BEFORE OM TO MAINTAIN SEPARATION. TWR ASKED OUR AIRSPD. WHEN WE SAID WE STARTED TO SLOW, WE WERE REMINDED WE WERE TO HOLD 170 KTS TO MARKER. LOOKING AT THIS SIT, WE SHOULD HAVE QUERIED TWR AS TO OUR SEPARATION OPPOSED TO TRYING TO MAINTAIN OUR OWN WITH TCASII.

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.