The flight was the second Metro III type-conversion training
flight for the co-pilot. Earlier that night, he had completed a
48-minute flight.
During the briefing prior to the second flight, the
check-and-training pilot indicated that he would give the co-pilot
a V1 cut during the takeoff. The co-pilot questioned the legality
of conducting the procedure at night. The check-and-training pilot
indicated that it was not illegal because the company operations
manual had been amended to permit the procedure. The crew then
proceeded to brief the instrument approach which was to be flown
following the V1 cut. There was no detailed discussion concerning
the technique for flying a V1 cut.
The co-pilot conducted the takeoff. Four seconds after the
aircraft became airborne, the check-and-training pilot retarded the
left engine power lever to flight-idle. The landing gear was
selected up 11 seconds later. After a further 20 seconds, the
aircraft struck the crown of a tree and then the ground about 350 m
beyond the upwind end of the runway and 210 m left of the extended
centreline. It caught fire and was destroyed. The co-pilot and
another trainee on board the aircraft were killed while the
check-and-training pilot received serious injuries.
The investigation found that the performance of the aircraft was
adversely affected by:
- the control inputs of the co-pilot; and
- the period the landing gear remained extended after the
simulated engine failure.
The check-and-training pilot had flown night V1 cut procedures
in a Metro III flight simulator, but had not flown the procedure in
the aircraft at night. He did not terminate the exercise, despite
indications that the aircraft was not maintaining V2 and that it
was descending. There were few external visual cues available to
the crew in the prevailing dark-night conditions. This affected
their ability to maintain awareness of the aircraft's position and
performance as the flight progressed.
A number of organisational factors were identified which
influenced the aviation environment in which the flight operated.
These included, on the part of the operating company:
- an inadequate Metro III endorsement training syllabus in the
company operations manual; - inadequate assessment of the risks involved in night V1 cuts;
and - assigning the check-and-training pilot a task for which he did
not possess adequate experience, knowledge, or skills.
Organisational factors involving the regulator included:
- a lack of enabling legislation prohibiting low-level night
asymmetric operations; - deficient requirements for co-pilot conversion training;
- inadequate advice given to the operator concerning night
asymmetric operations and the carriage of additional trainees on
training flights; - deficient training and approval process for check-and-training
pilots; and - insufficient quality control of the company operations
manual.
The investigation also determined that there was incomplete
understanding within the company, the regulating authority, and
some sections of the aviation industry of the possible effects of
engine flight-idle torque on aircraft performance. Inadequate
information on the matter in the aircraft flight manual contributed
to this.