JS41 crew slowed approach speed below ATC assigned speed before passing the final fix at iad.

Attributes
ACN	520009
Time
Date	200107
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iad.airport
State Reference	VA
Altitude	msl bound lower : 2000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad.tracon artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	Jetstream 41
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer only : 10r
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : atp
Experience	flight time last 90 days : 195 flight time total : 3400 flight time type : 1000
ASRS Report	520009
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer observation : company check pilot
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	inflight encounter : weather non adherence : clearance non adherence : company policies non adherence : far non adherence : published procedure other anomaly other anomaly other
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance controller : issued alert flight crew : executed go around
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were assigned a speed of 180 KIAS. Approach speed was approximately 125 KIAS. We were on the localizer at about 4000 ft MSL when cleared for the approach. Since we were high, we intercepted the GS outside the LOM. First officer elected to follow GS rather than have descended earlier to 1900 ft outside of LOM (the published minimum altitude for that segment of the approach. The first officer then misinterped his location/failed to remember and comply with the speed restr. We slowed to approach speed 1 or 2 mi outside of tille. ATC questioned our airspeed as we passed over tille. They then slowed following traffic and passed us to dulles tower. Tower vectored us off final for a go around. I assume that following traffic got too close behind us. I, obviously, failed to monitor the first officer's flying closely enough. First officer was hand flying, as autoplt was deferred. This increased workload and added to distraction that kept me from more closely monitoring the approach.

Original NASA ASRS Text

Title: JS41 CREW SLOWED APCH SPD BELOW ATC ASSIGNED SPD BEFORE PASSING THE FINAL FIX AT IAD.

Narrative: WE WERE ASSIGNED A SPD OF 180 KIAS. APCH SPD WAS APPROX 125 KIAS. WE WERE ON THE LOC AT ABOUT 4000 FT MSL WHEN CLRED FOR THE APCH. SINCE WE WERE HIGH, WE INTERCEPTED THE GS OUTSIDE THE LOM. FO ELECTED TO FOLLOW GS RATHER THAN HAVE DSNDED EARLIER TO 1900 FT OUTSIDE OF LOM (THE PUBLISHED MINIMUM ALT FOR THAT SEGMENT OF THE APCH. THE FO THEN MISINTERPED HIS LOCATION/FAILED TO REMEMBER AND COMPLY WITH THE SPD RESTR. WE SLOWED TO APCH SPD 1 OR 2 MI OUTSIDE OF TILLE. ATC QUESTIONED OUR AIRSPD AS WE PASSED OVER TILLE. THEY THEN SLOWED FOLLOWING TFC AND PASSED US TO DULLES TWR. TWR VECTORED US OFF FINAL FOR A GAR. I ASSUME THAT FOLLOWING TFC GOT TOO CLOSE BEHIND US. I, OBVIOUSLY, FAILED TO MONITOR THE FO'S FLYING CLOSELY ENOUGH. FO WAS HAND FLYING, AS AUTOPLT WAS DEFERRED. THIS INCREASED WORKLOAD AND ADDED TO DISTR THAT KEPT ME FROM MORE CLOSELY MONITORING THE APCH.

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.