My 2 cents
1 - fatigue
2 - poor schedule
causing
3 - several TOGA cancellations due to intermittent WOW and computer logic.
4 - Wrong throttle moved.
5 - Landing gear ordered prematurely up.
contributing factors during test flight:
- one engine turned off intentionally
- low altitude flight of 10 ft AGL
The part that interested me most was #3, and #5.
page 33
The pilot flying pressed the TOGA button on the right TQL to initiate a go-around
and, according to the cockpit voice recorder, called out “go-around.”
Almost simultaneously, at 05:23:28:70, the main landing gear touched the RW
and as a result of left main LG shock strut compression a/c avionics complex
received WOW (weight on wheels) signal.
In response to WOW signal and in accordance with AFCS logic and SC AWO
316 requirements, the left A/T disengaged automatically. At the moment of left
A/T disengagement, the left engine TQL was at 16.59°.
The pilot flying noticed at the primary flight display that the go-around mode had
not engaged. He also noticed that the flight director was not available.
After the AP disconnected, the pilot flying attempted go-around by pressing the
TOGA button on the right throttle immediately prior to the landing gear touching
the runway at 05:23:28.7. The FTI 52 recorded a short “pulse” of GA mode
engagement, which confirms that the signal from the TOGA button reached the
auto flight system and its attempt to engage the GA mode on this computational
step.
At 05:23:29.5, the left LG WOW status appeared. Therefore, in accordance with
the auto flight system logics, the A/T system was disconnected. GA engagement
was inhibited by an asynchronous acquiring of WOW status by the two auto flight
system master channel computers. The GA was not displayed in PFD. So, at
05:23:29.5 the following events had simultaneously occurred:
Actual landing touchdown, A/T disconnect and GA mode engagement inhibit.
The main landing gear only touched the runway at 05:23:28:70 for a brief
moment (0.4 seconds) and then the airplane started to climb again at
05:23:29:10.
page 34
At 05:23:30 the right engine’s SOV 53 closed as it had previously been set to
failure mode by the ATTCS panel and shut down using the ENG MASTER
SWITCH.
At this point the AP, the FD, the left A/T and the right A/T were all selected OFF,
as was the right engine. The left engine was delivering thrust at TQL 16.59°,
slightly higher than idle. Manual input from the operational engine (left engine)
was therefore required to perform the go-around.
The pilot flying started to perform go around in manual mode, by setting the right
(inoperative) engine TQL to TO/GA.
The pilot flying pitched the airplane up and the airplane started climbing.
According to the CVR, no POSITIVE CLIMB callout was made.The pilot flying
ordered landing gear retraction at 05:23:34. The landing gear was selected to up
at 05:23:36 by the pilot monitoring.
The left TQL remained at 16.59 deg, until the pilot flying discovered his mistake
two seconds before the airplane hit the runway and put the left TQL to TO/GA.
By then, the throttle input on the left engine was too late.
Last edited by alph2z; 31st Mar 2016 at 02:45.