A B737 pushback crew began push before brakes were released; resulting in broken shear pins in the t...

Attributes
ACN	795440
Time
Date	200807
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : pushback
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	795440
Events
Anomaly	non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

When given clearance to push from gate; I told the ground crew 'cleared to push; brakes released.' I used the wrong sequence. The plane was immediately pushed and I had not released brakes. The tow bar broke the shear pins. A nosewheel steering inspection was performed and no damage was seen. A new tow bar was used and we pushed out.

Original NASA ASRS Text

Title: A B737 PUSHBACK CREW BEGAN PUSH BEFORE BRAKES WERE RELEASED; RESULTING IN BROKEN SHEAR PINS IN THE TOW BAR.

Narrative: WHEN GIVEN CLRNC TO PUSH FROM GATE; I TOLD THE GND CREW 'CLRED TO PUSH; BRAKES RELEASED.' I USED THE WRONG SEQUENCE. THE PLANE WAS IMMEDIATELY PUSHED AND I HAD NOT RELEASED BRAKES. THE TOW BAR BROKE THE SHEAR PINS. A NOSEWHEEL STEERING INSPECTION WAS PERFORMED AND NO DAMAGE WAS SEEN. A NEW TOW BAR WAS USED AND WE PUSHED OUT.

Data retrieved from NASA's ASRS site as of May 2009 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.

A B737 pushback crew began push before brakes were released; resulting in broken shear pins in the tow bar.