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A B737 first officer was told to maintain 250 KTS by C90. The first officer did not understand this instruction and violated his airspeed restr.
| Attributes | |
| ACN | 491070 |
| Time | |
| Date | 200011 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : ord.airport |
| State Reference | IL |
| Altitude | msl single value : 11300 |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : c90.tracon tower : ord.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure sid : n/s |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial pilot : multi engine |
| ASRS Report | 491070 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | non adherence : clearance non adherence : published procedure other anomaly |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued advisory |
| Consequence | faa : reviewed incident with flight crew other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
At 1000 ft afl on takeoff, I commanded VNAV. Tower, at about 3500 ft, told us 'maintain 250 KTS, contact departure.' since a big departure push was in progress, in my mind, I took the 250 (mistakenly) as 250 KTS as soon as possible. We contacted departure with current altitude and assigned altitude only. Departure assigned us 13000 ft. ATC subsequently instructed the aircraft in front of us 'best forward speed as soon as possible out of 10000 ft.' at 10000 ft, I accelerated toward the VNAV computed speed of about 334 KTS. Around 320 KTS and 11300 ft, ATC said 'maintain 250 KTS until advised.' I promptly brought the power back and pitched up to slow quickly, remembering the 'maintain 250 KTS' previously issued. It would have helped if we were originally instructed to 'maintain 250 KTS until advised' it paints a more concrete picture in my mind. I'm not ducking my responsibility on this, but 'until advised' would more quickly prompt me to change/command the flight guidance to not accelerate at 10000 ft (ie, VNAV speed intervention 250 KTS or level change with speed set at 250 KTS). Also, when we checked on to departure, we didn't state that we were assigned/restr to 250 KTS. So, a confirmation from ATC may have helped.
Original NASA ASRS Text
Title: A B737 FO WAS TOLD TO MAINTAIN 250 KTS BY C90. THE FO DID NOT UNDERSTAND THIS INSTRUCTION AND VIOLATED HIS AIRSPD RESTR.
Narrative: AT 1000 FT AFL ON TKOF, I COMMANDED VNAV. TWR, AT ABOUT 3500 FT, TOLD US 'MAINTAIN 250 KTS, CONTACT DEP.' SINCE A BIG DEP PUSH WAS IN PROGRESS, IN MY MIND, I TOOK THE 250 (MISTAKENLY) AS 250 KTS ASAP. WE CONTACTED DEP WITH CURRENT ALT AND ASSIGNED ALT ONLY. DEP ASSIGNED US 13000 FT. ATC SUBSEQUENTLY INSTRUCTED THE ACFT IN FRONT OF US 'BEST FORWARD SPD ASAP OUT OF 10000 FT.' AT 10000 FT, I ACCELERATED TOWARD THE VNAV COMPUTED SPD OF ABOUT 334 KTS. AROUND 320 KTS AND 11300 FT, ATC SAID 'MAINTAIN 250 KTS UNTIL ADVISED.' I PROMPTLY BROUGHT THE PWR BACK AND PITCHED UP TO SLOW QUICKLY, REMEMBERING THE 'MAINTAIN 250 KTS' PREVIOUSLY ISSUED. IT WOULD HAVE HELPED IF WE WERE ORIGINALLY INSTRUCTED TO 'MAINTAIN 250 KTS UNTIL ADVISED' IT PAINTS A MORE CONCRETE PICTURE IN MY MIND. I'M NOT DUCKING MY RESPONSIBILITY ON THIS, BUT 'UNTIL ADVISED' WOULD MORE QUICKLY PROMPT ME TO CHANGE/COMMAND THE FLT GUIDANCE TO NOT ACCELERATE AT 10000 FT (IE, VNAV SPD INTERVENTION 250 KTS OR LEVEL CHANGE WITH SPD SET AT 250 KTS). ALSO, WHEN WE CHKED ON TO DEP, WE DIDN'T STATE THAT WE WERE ASSIGNED/RESTR TO 250 KTS. SO, A CONFIRMATION FROM ATC MAY HAVE HELPED.
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.