Archives For TOW

qantas-vh-vzr-737-838-640x353

Deconstructing a tail strike incident

On August 1 last year, a Qantas 737-838 (VH-VZR) suffered a tail-strike while taking off from Sydney airport, and this week the ATSB released it’s report on the incident. The ATSB narrative is essentially that when working out the plane’s Takeoff Weight (TOW) on a notepad, the captain forgot to carry the ‘1’ which resulted in an erroneous weight of 66,400kg rather than 76,400kg. Subsequently the co-pilot made a transposition error when carrying out the same calculation on the Qantas iPad resident on-board performance tool (OPT), in this case transposing 6 for 7 in the fuel weight resulting in entering 66,400kg into the OPT. A cross check of the OPT calculated Vref40 speed value against that calculated by the FMC (which uses the aircraft Zero Fuel Weight (ZFW) input rather than TOW to calculate Vref40) would have picked the error up, but the crew mis-interpreted the check and so it was not performed correctly. Continue Reading…