B767 crew had illegal takeoff at sfo because performance decrement for MEL'ed inoperative anti-skid ...

Attributes
ACN	529963
Time
Date	200111
Day	Sat
Place
Locale Reference	airport : sf0.airport
State Reference	CA
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	529963
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical maintenance problem : non compliance with mel non adherence : far non adherence : published procedure non adherence : company policies
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted other
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft Company
Primary Problem	Company

Narrative:

MEL discrepancy. Maintenance placarded anti-skid inoperative we ran through the requirements and I calculated that the V1 reduction for the runway planned put us 2 or 3 KTS below minimum V1 making us illegal. I called dispatch and she ran through the procedure but she started with a higher runway limit weight that was based on air conditioning off and got a V1 slightly above the min V1 making departure legal. After takeoff I ran my own calculations based on the higer runway limit. Air conditioning off and got a V1 slightly above the minimum V1 making the departure legal. Her calculations seemed good so we departed based on the higher runway limit, air-conditioning off and still came up a couple KTS below being legal. On arrival I called her and she realized she had done the calculations for flaps 5 degrees takeoff instead of the required flaps 15 degrees, the calculations required make it easy for mistakes like the one the dispatcher made and I also should not have assumed that her higher starting runway limit was the reason for the differences in our outcome without rechking it myself.

Original NASA ASRS Text

Title: B767 CREW HAD ILLEGAL TKOF AT SFO BECAUSE PERFORMANCE DECREMENT FOR MEL'ED INOP ANTI-SKID WAS INCORRECTLY APPLIED.

Narrative: MEL DISCREPANCY. MAINT PLACARDED ANTI-SKID INOP WE RAN THROUGH THE REQUIREMENTS AND I CALCULATED THAT THE V1 REDUCTION FOR THE RWY PLANNED PUT US 2 OR 3 KTS BELOW MINIMUM V1 MAKING US ILLEGAL. I CALLED DISPATCH AND SHE RAN THROUGH THE PROC BUT SHE STARTED WITH A HIGHER RWY LIMIT WT THAT WAS BASED ON AIR CONDITIONING OFF AND GOT A V1 SLIGHTLY ABOVE THE MIN V1 MAKING DEP LEGAL. AFTER TKOF I RAN MY OWN CALCULATIONS BASED ON THE HIGER RWY LIMIT. AIR CONDITIONING OFF AND GOT A V1 SLIGHTLY ABOVE THE MINIMUM V1 MAKING THE DEP LEGAL. HER CALCULATIONS SEEMED GOOD SO WE DEPARTED BASED ON THE HIGHER RWY LIMIT, AIR-CONDITIONING OFF AND STILL CAME UP A COUPLE KTS BELOW BEING LEGAL. ON ARR I CALLED HER AND SHE REALIZED SHE HAD DONE THE CALCULATIONS FOR FLAPS 5 DEGS TKOF INSTEAD OF THE REQUIRED FLAPS 15 DEGS, THE CALCULATIONS REQUIRED MAKE IT EASY FOR MISTAKES LIKE THE ONE THE DISPATCHER MADE AND I ALSO SHOULD NOT HAVE ASSUMED THAT HER HIGHER STARTING RWY LIMIT WAS THE REASON FOR THE DIFFERENCES IN OUR OUTCOME WITHOUT RECHKING IT MYSELF.

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.

B767 crew had illegal takeoff at sfo because performance decrement for MEL'ed inoperative anti-skid was incorrectly applied.