For those who think stabilised approaches are a bad thing, an excerpt from the manufacturers memo regarding the Iberia A340 accident in Quito.
The CVR records confirm the crew intent was initially to follow the ILS until sufficient visual references were available, then to leave the Glide Slope to visually capture and follow the PAPI path and use the full runway for landing.
The approach was performed with both AP1&2 engaged in LOC and GLIDE track modes, A/THR engaged in managed speed mode. Till touchdown, A/THR maintained the VAPP. For final approach, the aircraft was configured to land (gear down, auto-brake set to HIGH, ground spoilers armed, flaps fully extended). Landing weight was 249t, Vapp 151 kt. Given the altitude and the tailwind, the True Air Speed was 181kt and the Ground Speed 189kt.
While AP 1+2 were engaged, the aircraft remained stabilized on the LOC and GLIDE.
Runway 35 was in sight just prior to minimum, DA(H) being 9850ft(652ft).
AP 1+2 were disconnected at the minimum. The PF applied nose-down stick inputs to reach the PAPI flight path. This resulted into an increased rate of descent above 1400ft/mn between 450ft and 150ft radio-altitude. The GPWS "SINK RATE" warning was triggered at 270ft radio-altitude, it was followed by transient nose-up inputs from the PF.
The "SINK RATE" warning was triggered again below 50ft AGL.
The touch-down occurred at about 200m after the full runway threshold (remaining distance was 2920 m).
The landing was extremely hard (more than 3g vertical acceleration, about 19ft/sec 1100ft/mn), which lead to:
- Breakage of the lower articulation link of both Main Landing Gear (MLG);
- Abrupt derotation of both bogie beams;
- Burst at impact of all 4 MLG front wheels;
- And damage of the wiring looms of RH and LH boogie proximity sensors that are
used to detect the GROUND condition hence allowing engine thrust reversers deployment.