PRELIMINARY REPORT ON ACCIDENT INVOLVING ASSOCIATED AIRLINE EMBRAER 120 AIRCRAFT REGISTERED 5N-BJY WHICH OCCURRED AT MMA ON THURSDAY 3RD OCTOBER, 2013. The following information has been
determined from preliminary readout and
analysis of flight 361’s flight recorders. Flight
361 was equipped with both a COCKPIT VOICE
RECORDER and a FLIGHT DATA RECORDER. Both
recorders were replayed at the Accident Investigation Bureau’s recently acquired flight
recorder laboratory located in Abuja.
International flight recorder experts from
Canada who designed the laboratory assisted
the investigation team with the readout and
analysis process along with representatives from the aircraft manufacturer and aircraft
operator, Associated Airlines. We are
conducting the investigation in accordance
with the provisions of International Civil
Aviation Organization (ICAO) Annex 13, of
which Nigeria is a member State. The flight data recorder or FDR contained
approximately 47 hours of data in solid state
memory. The recorder downloaded without
issue. There were approximately 50
parameters recorded. A few parameters were
not working properly however we do not think, in this particular case, that it will hamper
the overall investigation. The cockpit voice recorder or CVR was an older
generation magnetic tape based device. The
CVR’s magnetic tape recording was removed
from the unit and replayed on an open reel 4
track tape deck specially adapted for replaying
CVR’s of this type. The CVR contained 32 and one half minutes of audio which included the
internal conversation of the two pilots, radio
calls and the overall aural environment in the
cockpit on the cockpit area microphone. The
CVR was of good quality and the team is in the
process of generating a complete transcript of all relevant information. The AIB plans to
release the transcript as part of its final report of
the accident however the actual recording is,
under international protocol, sensitive and
therefore privileged information and will not be
released at any time. The following represents information that has
been determined from our preliminary
assessment of both flight recorders: The crew discussed some concerns about the
aircraft prior to departure but at this time we
are not prepared to elaborate on those
concerns as there remains a lot of work to
complete on the CVR analysis in order to
determine the specific nature of the crew’s concerns. Associated 361 was cleared for take-off on
runway one eight left at Lagos international
airport. The wind was calm and weather is not
considered a factor in this accident.
Approximately 4 seconds after engine power
was advanced to commence the take-off roll, the crew received an automated warning from
the onboard computer voice which consisted
of three chimes followed by “Take-off Flaps…
Take-off Flaps”. This is a configuration
warning that suggests that the flaps were not
in the correct position for take-off and there is some evidence that the crew may have chosen
not to use flaps for the take-off. The warning
did not appear to come as any surprise to the
crew and they continued normally with the
take-off. This warning continues throughout
the take-off roll. As we are in the process of verifying the accuracy of the flight data, we
have not yet been able to confirm the actual
flap setting however we expect to determine
this in the fullness of time. It was determined from the CVR that the pilot
flying was the Captain and the pilot monitoring
and assisting was the First Officer. The ‘set power‘ call was made by the Captain
and the ‘power is set’ call was confirmed by the
First Officer as expected in normal operations.
Approximately 3 seconds after the ‘power is
set’ call, the First Officer noted that the aircraft
was moving slowly. Approximately 7 seconds after the ‘power is set’ call, the internal Aircraft
Voice warning system could be heard stating
‘Take off Flaps, Auto Feather’. Auto feather
refers to the pitch of the propeller blades. In
the feather position, the propeller does not
produce any thrust. The FDR contains several engine related parameters which the AIB is
studying. At this time, we can state that the
Right engine appears to be producing
considerably less thrust than the Left engine.
The left engine appeared to be working
normally. The aircraft automated voice continued to repeat ‘Take-off Flaps, Auto
Feather’. The physical examination of the wreckage
revealed that the right engine propeller was in
the feather position and the engine fire handle
was pulled/activated. The standard ‘eighty knots’ call was made by
the First Officer. The first evidence that the crew
indicated that there was a problem with the
take-off roll was immediately following the
‘eighty knots’ call. The First Officer asked if the
take-off should be abortedapproximately 12 seconds after the ‘eighty knots’ callout. Our
investigation team estimates the airspeed to be
approximately 95 knots. Airspeed was one of
the parameters that, while working in the
cockpit, appeared not to be working on the
Flight Data Recorder. We were able to estimate the speed based on the radar data that we
synchronized to the FDR and CVR but it is very
approximate because of this. In response to
the First Officer’s question to abort, the Captain
indicated that they should continue and they
continued the take-off roll. The crew did not make a ‘V1’ call or a Vr’ call. V1 is the speed at
which a decision to abort or continue a take-off
is made. Vr is the speed at which it is planned to
rotate the aircraft. Normally the non-flying pilot
calls both the V1 and the Vr speeds. When Vr is
called the flying pilot pulls back on the control column and the aircraft is rotated (pitched up)
to climb away from the runway. During the
rotation, the First Officer stated ‘gently’, which
we believe reflects concern that the aircraft is
not performing normally and therefore needs
to be rotated very gently so as not to aerodynamically stall the aircraft. The First Officer indicated that the aircraft was
not climbing and advised the Captain who was
flying not to stall the aircraft. Higher climb
angles can cause an aerodynamic stall. If the
aircraft is not producing enough overall thrust,
it is difficult or impossible to climb without the risk of an aerodynamic stall. Immediately after lift-off, the aircraft slowly
veered off the runway heading to the right and
was not climbing properly. This aircraft
behavior appears to have resulted in the Air
Traffic Controller asking Flight 361 if operation
was normal. Flight 361 never responded. Less than 10 seconds after rotation of the
aircraft to climb away from the runway, the stall
warning sounded in the cockpit and continued
to the end of the recording. The flight data
shows characteristics consistent with an
aerodynamic stall. 31 seconds after the stall warning was heard,
the aircraft impacted the ground in a nose
down near 90 degree right bank. The investigation is focussing on the following: 1) Mechanical and electronic engine control
issues related to the Right engine and Right
engine propeller systems. 2) Aural warnings related to auto-feather and
the flap settings required for takeoff. 3) Take-off configuration issues with respect
to flap settings. 4) Crew decision making and training with
respect to proceeding with the flight despite
concerns regarding the aircraft’s suitability for
flight. 5) When and how the number 2 engine fire
handle was pulled. 6) Standard operating procedures with
respect to continuing the take-off roll despite
continuous automated voice warnings of both
‘take-off flaps’ and ‘auto feather’ when there
was ample time to abort the take-off. 7) The airline management’s safety culture
fostered throughout the airline. We are in the process of developing a
comprehensive computer reconstruction of the
flight which will help our team understand the
sequence of events and will ultimately help us
communicate our findings to the aviation
community and the general public. At this time we have no urgent safety
recommendations. We will not wait for the final
report to issue safety recommendations should any issue arise that we feel needs immediate attention. thenationonlineng.net/new/full-preliminary-report-on-lagos-plane-crash/

Poor human judgement, the pilot is not alive to suffer for his negligience, he has paid the supreme price. May the soul of the departed rest in peace