Speed deviation when clearance misinterped.

Attributes
ACN	479209
Time
Date	200007
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lax.airport
State Reference	CA
Altitude	msl bound lower : 12000 msl bound upper : 17000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : vacating altitude
Route In Use	departure sid : gorman 2
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
ASRS Report	479209
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	479210
Events
Anomaly	non adherence : clearance other anomaly
Independent Detector	other controllerb
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Departing lax runway heading, we were assigned a hard airspeed of 250 KIAS. After receiving numerous vectors and step climb altitudes, we were given a vector to rejoin the departure radial to gmn. We misinterped our clearance to include clearance to accelerate above 10000 ft MSL. Passing 17000 ft, the ZLA controller asked what our airspeed was. We replied 290 KIAS. We were instructed to maintain 290 KIAS and were reminded that we had previously been assigned 250 KIAS by socal departure control. Supplemental information from acn 479210: I thought I heard 'resume normal speed.' out of 10000 ft, I started to accelerate. I did not hear the first officer's acknowledgement or check in, so no warning bells were ringing for me on the speed. I honestly thought we had been given normal speed. I should not have assumed that the first officer had heard the same thing I did and when I didn't hear his readback I should have asked for clarification just to make sure.

Original NASA ASRS Text

Title: SPD DEV WHEN CLRNC MISINTERPED.

Narrative: DEPARTING LAX RWY HDG, WE WERE ASSIGNED A HARD AIRSPD OF 250 KIAS. AFTER RECEIVING NUMEROUS VECTORS AND STEP CLB ALTS, WE WERE GIVEN A VECTOR TO REJOIN THE DEP RADIAL TO GMN. WE MISINTERPED OUR CLRNC TO INCLUDE CLRNC TO ACCELERATE ABOVE 10000 FT MSL. PASSING 17000 FT, THE ZLA CTLR ASKED WHAT OUR AIRSPD WAS. WE REPLIED 290 KIAS. WE WERE INSTRUCTED TO MAINTAIN 290 KIAS AND WERE REMINDED THAT WE HAD PREVIOUSLY BEEN ASSIGNED 250 KIAS BY SOCAL DEP CTL. SUPPLEMENTAL INFO FROM ACN 479210: I THOUGHT I HEARD 'RESUME NORMAL SPD.' OUT OF 10000 FT, I STARTED TO ACCELERATE. I DID NOT HEAR THE FO'S ACKNOWLEDGEMENT OR CHK IN, SO NO WARNING BELLS WERE RINGING FOR ME ON THE SPD. I HONESTLY THOUGHT WE HAD BEEN GIVEN NORMAL SPD. I SHOULD NOT HAVE ASSUMED THAT THE FO HAD HEARD THE SAME THING I DID AND WHEN I DIDN'T HEAR HIS READBACK I SHOULD HAVE ASKED FOR CLARIFICATION JUST TO MAKE SURE.

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.