Pilot violated the speed restriction on the profile descent clearance.

Attributes
ACN	166750
Time
Date	199012
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : oak airport : sfo
State Reference	CA
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	arrival star : star enroute airway : oak
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 8
ASRS Report	166750
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance other anomaly
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Many controllers have noticed lately that aircraft crews misinterpret or deviate from speed instructions on stars into sfo airport. In the case of bsr 5 STAR (sfo runway 28 profile descent) the speed is published on the STAR. On the modesto two and golden gate two arrs, pilots are instructed to cross a fix at 11000' 'at two five zero KTS.' in several cases the air crews have reduced to less than the assigned 250 KT restriction. Upon query today medium large transport on runway 28 profile descent advised that they had slowed to 210 KTS, for 'gate problems'. The aim allows a +/- 10 KTS variance, but to reduce to 210 KTS west/O receiving clearance is a deviation of FARS. So many time we establish a sequence of arrs, relying on assigned/published speeds to maintain spacing. If the pilots slow to some (discretionary) speed below what is assigned and expected, we get into overtake situations causing additional delays for following aircraft. 'X at 11000' at 250 KTS' means at 250 KTS not '250 or less.'

Original NASA ASRS Text

Title: PLT VIOLATED THE SPEED RESTRICTION ON THE PROFILE DESCENT CLRNC.

Narrative: MANY CTLRS HAVE NOTICED LATELY THAT ACFT CREWS MISINTERPRET OR DEVIATE FROM SPD INSTRUCTIONS ON STARS INTO SFO ARPT. IN THE CASE OF BSR 5 STAR (SFO RWY 28 PROFILE DSNT) THE SPD IS PUBLISHED ON THE STAR. ON THE MODESTO TWO AND GOLDEN GATE TWO ARRS, PLTS ARE INSTRUCTED TO CROSS A FIX AT 11000' 'AT TWO FIVE ZERO KTS.' IN SEVERAL CASES THE AIR CREWS HAVE REDUCED TO LESS THAN THE ASSIGNED 250 KT RESTRICTION. UPON QUERY TODAY MLG ON RWY 28 PROFILE DSNT ADVISED THAT THEY HAD SLOWED TO 210 KTS, FOR 'GATE PROBS'. THE AIM ALLOWS A +/- 10 KTS VARIANCE, BUT TO REDUCE TO 210 KTS W/O RECEIVING CLRNC IS A DEV OF FARS. SO MANY TIME WE ESTABLISH A SEQUENCE OF ARRS, RELYING ON ASSIGNED/PUBLISHED SPDS TO MAINTAIN SPACING. IF THE PLTS SLOW TO SOME (DISCRETIONARY) SPD BELOW WHAT IS ASSIGNED AND EXPECTED, WE GET INTO OVERTAKE SITUATIONS CAUSING ADDITIONAL DELAYS FOR FOLLOWING ACFT. 'X AT 11000' AT 250 KTS' MEANS AT 250 KTS NOT '250 OR LESS.'

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.