Narrative:

Taxiing out to runway 8 in den; we agreed to taxi out on 1 engine to save fuel on the long taxi. About halfway to the runway; captain asked for the 'second engine start' checklist; which states: yellow pump -- off; engine #2 -- start; anti-ice -- on/off; off steering and brakes; engine #2 generator -- on; APU generator/bleed -- on/off; ECAM status-- check. After engine #2 started; I immediately began the APU shutdown sequence; which is normal after engine #2 start for 2 engine taxi-out. When the callout for 'off steering and brakes' call was made; the captain advised me to wait because he was having to make constant steering and brake inputs to maintain aircraft control. Shortly thereafter; the aircraft electrical system performed a 'hard xfer' of electrical power; resulting in a momentary loss of steering and an abrupt uncommanded braking input. Thanks to an exceptionally sharp captain; aircraft control was quickly regained without further incident. After regaining control; we decided that the best course of action would be to park the aircraft in a run-up area; figure out what happened; and determine whether or not the aircraft was malfunctioning. Maintenance was consulted using radio communication. After discussion; it was easily determined that the cause of the hard power xfer and resulting uncommanded inputs were the result of the APU being shut down out of sequence. It states very clearly in fom volume 1 that the items on the second engine start checklist are to be performed in order and as a read-do checklist. This is also clearly stated at the top of the checklist itself. The only explanation I can give as to why I committed this error is that I have become very comfortable in the aircraft. The aircraft was functioning normally prior to takeoff. We also talked to the flight attendants about it prior to departure who told us that everyone; including themselves; were already in their seats; and no one had been injured; but that the sudden braking had shaken a few of them up. I can guarantee you that this is 1 crew member who will not repeat this error. After the incident; I reviewed the checklist as well as volume 1 and have idented my obvious error. The only way I can think of to help reduce the likelihood of an occurrence would may be to include this anecdote in future training to emphasize following the second engine start checklist in order; as a read/do. Items on checklist completed out of order.

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Original NASA ASRS Text

Title: A319 CREW EXPERIENCES MOMENTARY BRAKE AND STEERING ANOMALIES DURING TAXI; AFTER SECOND ENGINE START.

Narrative: TAXIING OUT TO RWY 8 IN DEN; WE AGREED TO TAXI OUT ON 1 ENG TO SAVE FUEL ON THE LONG TAXI. ABOUT HALFWAY TO THE RWY; CAPT ASKED FOR THE 'SECOND ENG START' CHKLIST; WHICH STATES: YELLOW PUMP -- OFF; ENG #2 -- START; ANTI-ICE -- ON/OFF; OFF STEERING AND BRAKES; ENG #2 GENERATOR -- ON; APU GENERATOR/BLEED -- ON/OFF; ECAM STATUS-- CHK. AFTER ENG #2 STARTED; I IMMEDIATELY BEGAN THE APU SHUTDOWN SEQUENCE; WHICH IS NORMAL AFTER ENG #2 START FOR 2 ENG TAXI-OUT. WHEN THE CALLOUT FOR 'OFF STEERING AND BRAKES' CALL WAS MADE; THE CAPT ADVISED ME TO WAIT BECAUSE HE WAS HAVING TO MAKE CONSTANT STEERING AND BRAKE INPUTS TO MAINTAIN ACFT CTL. SHORTLY THEREAFTER; THE ACFT ELECTRICAL SYS PERFORMED A 'HARD XFER' OF ELECTRICAL PWR; RESULTING IN A MOMENTARY LOSS OF STEERING AND AN ABRUPT UNCOMMANDED BRAKING INPUT. THANKS TO AN EXCEPTIONALLY SHARP CAPT; ACFT CTL WAS QUICKLY REGAINED WITHOUT FURTHER INCIDENT. AFTER REGAINING CTL; WE DECIDED THAT THE BEST COURSE OF ACTION WOULD BE TO PARK THE ACFT IN A RUN-UP AREA; FIGURE OUT WHAT HAPPENED; AND DETERMINE WHETHER OR NOT THE ACFT WAS MALFUNCTIONING. MAINT WAS CONSULTED USING RADIO COM. AFTER DISCUSSION; IT WAS EASILY DETERMINED THAT THE CAUSE OF THE HARD PWR XFER AND RESULTING UNCOMMANDED INPUTS WERE THE RESULT OF THE APU BEING SHUT DOWN OUT OF SEQUENCE. IT STATES VERY CLRLY IN FOM VOLUME 1 THAT THE ITEMS ON THE SECOND ENG START CHKLIST ARE TO BE PERFORMED IN ORDER AND AS A READ-DO CHKLIST. THIS IS ALSO CLRLY STATED AT THE TOP OF THE CHKLIST ITSELF. THE ONLY EXPLANATION I CAN GIVE AS TO WHY I COMMITTED THIS ERROR IS THAT I HAVE BECOME VERY COMFORTABLE IN THE ACFT. THE ACFT WAS FUNCTIONING NORMALLY PRIOR TO TKOF. WE ALSO TALKED TO THE FLT ATTENDANTS ABOUT IT PRIOR TO DEP WHO TOLD US THAT EVERYONE; INCLUDING THEMSELVES; WERE ALREADY IN THEIR SEATS; AND NO ONE HAD BEEN INJURED; BUT THAT THE SUDDEN BRAKING HAD SHAKEN A FEW OF THEM UP. I CAN GUARANTEE YOU THAT THIS IS 1 CREW MEMBER WHO WILL NOT REPEAT THIS ERROR. AFTER THE INCIDENT; I REVIEWED THE CHKLIST AS WELL AS VOLUME 1 AND HAVE IDENTED MY OBVIOUS ERROR. THE ONLY WAY I CAN THINK OF TO HELP REDUCE THE LIKELIHOOD OF AN OCCURRENCE WOULD MAY BE TO INCLUDE THIS ANECDOTE IN FUTURE TRAINING TO EMPHASIZE FOLLOWING THE SECOND ENG START CHKLIST IN ORDER; AS A READ/DO. ITEMS ON CHKLIST COMPLETED OUT OF ORDER.

Data retrieved from NASA's ASRS site as of January 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.