ikramerica From United States of America, joined May 2005, 21715 posts, RR: 59
Reply 1, posted (5 years 1 month 1 week 5 days 17 hours ago) and read 2747 times:
Good that they are being proactive here despite no actual overuns, injuries or fatalities. Wish the governing authority for auto safety were as insistent that Toyota install new software before people died, not after 50 deaths.
We focus so much on air safety in this country when most people who die in vehicle accidents die in cars and on bicycles, both on a shear volume basis and a "per 100k miles traveled" basis.
Of all the things to worry about... the Wookie has no pants.
UA777222 From United States of America, joined Dec 2003, 3348 posts, RR: 11
Reply 2, posted (5 years 1 month 1 week 5 days 14 hours ago) and read 2026 times:
The FAA have released Airworthiness Directive AD_2010_06_09 requiring operators of Boeing 777-200, -200LR,-300,-300ER and Boeing 777F to install new software into all three flight director computers (left, center, right) within 90 days following April 1st in order to prevent inadvertent engagement of the autopilot on the ground during the takeoff run and in order to fix too low a climb gradient during takeoffs with one engine inoperative.
The FAA reported, that there had been 9 occurrences of rejected takeoffs above decision speed (V1) following inadvertent activation of the autopilot during the ground roll since 1995 (for example see: Incident: ANZ B772 at Tokyo on Jan 31st 2010, rejected takeoff and Incident: Air France B773 at Lagos on Jan 12th 2010, rejected takeoff). This activation of the autopilot results in higher than usual control forces necessary to rotate the aircraft (editorial note: leading crews to believe the airplane won't fly and reject takeoff during rotation of the aircraft). This scenario increases the risk of runway overruns.
At the same time Boeing company discovered during simulator tests, that the autoflight software maintains a climb gradient that is "less than optimal for obstacle clearance during a one-engine takeoff (performance-limited) situation". This scenario could lead to failure of clearing obstacles during a performance limited takeoff.
Both scenarios could lead to potentially catastrophic results, the FAA reasons to justify the immediate release of the Airworthiness Directive and require compliance within 90 days.