757 has speed deviation on descent.

Attributes
ACN	304380
Time
Date	199505
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dfw
State Reference	TX
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	304380
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
Events
Anomaly	non adherence : clearance other anomaly
Independent Detector	other controllera
Resolutory Action	other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On vectors to runway 18R at dfw assigned airspeed was 210 KTS. ATC asked if we would be able to get down. I answered yes, incorrectly assuming that I would be free to get down any way that I could, and reduced to a flap speed that accelerated our descent. Shortly after this ATC asked our speed, which was by now below 210 KTS, and mentioned that they had not authority/authorized a speed reduction. ATC asked us to increase to 180 KTS until the marker, then contact the tower, etc. It was my error to reduce without their concurrence.

Original NASA ASRS Text

Title: 757 HAS SPD DEV ON DSCNT.

Narrative: ON VECTORS TO RWY 18R AT DFW ASSIGNED AIRSPD WAS 210 KTS. ATC ASKED IF WE WOULD BE ABLE TO GET DOWN. I ANSWERED YES, INCORRECTLY ASSUMING THAT I WOULD BE FREE TO GET DOWN ANY WAY THAT I COULD, AND REDUCED TO A FLAP SPD THAT ACCELERATED OUR DSCNT. SHORTLY AFTER THIS ATC ASKED OUR SPD, WHICH WAS BY NOW BELOW 210 KTS, AND MENTIONED THAT THEY HAD NOT AUTH A SPD REDUCTION. ATC ASKED US TO INCREASE TO 180 KTS UNTIL THE MARKER, THEN CONTACT THE TWR, ETC. IT WAS MY ERROR TO REDUCE WITHOUT THEIR CONCURRENCE.

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.