- The aircraft was significantly heavier than the pilot had
calculated. - The strip length available was insufficient for the intended
operation. - The takeoff procedure utilised by the pilot was incorrect.
- The pilot retracted the flaps at too low an airspeed.
- The aircraft's speed deteriorated to the point where a forced
landing was inevitable. - The pilot was forced to land on unsuitable terrain.
The accident
The investigation disclosed that although there was a minor
anomaly in one magneto, the engine was capable of delivering full
power. Accordingly, it is likely that the aircraft was flown off
the strip with full power available and applied, although it cannot
be discounted that there may have been a minor power reduction at
some stage due to the loose blade terminal in one magneto. However,
the power loss was almost certainly perceived rather than actual,
such perception being created by the aircraft sinking after the
flaps were raised at an airspeed lower than specified. The pilot
did not confirm a power loss from engine instrument
indications.
The pilot's natural tendency would be to maintain the nose up
climb attitude or raise the nose to try to maintain a climb. This
would have caused the speed to further reduce as was evidenced by
the pilot reporting that the airspeed dropped to 60 knots. When
this occurred the pilot lowered the nose to maintain airspeed and
controlled the flight path to avoid obstacles.The aircraft
continued to descend to a point where he had to reduce power and
flare the aircraft for the inevitable forced landing. The aircraft
landed heavily, most probably in a stalled condition.
Human factors
This accident therefore had very little to do with the pilots
ability to physically handle the aircraft. It instead involves a
corporate culture that allowed poor aircraft and crew selection,
inadequate flight preparation, incorrect briefing, and real or
perceived peer pressures on the pilot, to combine to place the
pilot into a situation from where an accident was essentially
inevitable. In other words, a human factors accident.
Human factors is about people in their living and working
situations; about their relationships with machines, with
procedures, and with the environment about them; and also about
their relationships with other people. (ICAO Circular
216-AN/131).
In applying certain techniques to the investigations of the
human factors involved in aircraft accidents, BASI uses the Reason
accident causation model, and, in the report into the 1993 Piper
Chieftain accident in Young NSW(BASI Investigation Report 9302743),
defined the common elements in an organisational accident as:
- latent failures which arise from deficiencies in managerial
policies and actions within one or more organisations. Often these
organisational factors are not immediately apparent and may lie
dormant for a considerable time. - local factors, being conditions which can affect the active
failures. These include such things as task and environmental
conditions. - active failures, being errors or violations which have an
immediate adverse effect. These unsafe acts are typically
associated with operational personnel. - inadequate or absent defences which fail to identify and
protect against technical and human failings arising from the three
previous elements.
Latent failures
Latent failures can be weaknesses or inadequacies within the
management of organisations which are not immediately apparent.
They can remain dormant for extended periods. These organisational
factors can impact upon the workplace to create an environment or a
corporate culture which increases the probability of errors or
violations, and weakens the systems defences which are designed to
minimise the consequences of unsafe acts. These latent failures
become apparent when they combine with local triggering events and
circumstances such as active failures, resulting in a breakdown of
the system.
In relation to this accident the organisational failures
included:
- inadequate management by the chief flying instructor who:
- scheduled an operating pilot with low total and no recent
experience on the type, - did not conduct a comprehensive briefing both prior to the
exercise and prior to the take off on the accident flight. - gave a briefing prior to the accident flight that did not
reflect the manufacturers requirements.
- scheduled an operating pilot with low total and no recent
- On a broader scale:
- the company did not provide adequate management of its human
resources. - the selection procedures for determining who should operate
which flight were inadequate.
- the company did not provide adequate management of its human
Active failures
Active failures are unsafe acts which most generally involve the
actions of operational personnel. Such failures can be divided into
two distinct groups; errors and violations. Errors may be of two
basic kinds and involve attentional slips or memory lapses, and
mistakes. Violations may be deliberate deviations from a regulated
practice or prescribed procedure.
The significant unsafe act in this occurrence was that the pilot
made a mistake by raising the flaps at too low an airspeed.
Local factors
These include such things as task and environmental conditions.
A significant local factors in this accident was that the chief
flying instructor was part of the ownership and management of the
company. Accordingly the authority gradient between the chief
flying instructor and pilot was very steep and the pilot would be
unlikely to doubt the judgement of a respected peer who had been
instrumental in his training and employment. Other local factors
were:
- the chief flying instructor did not adequately assess the
knowledge and skills of the pilot relative to this particular
operation - the pilot was neither experienced nor current on type.
- the pilot did not use the proper procedure to account for the
weight of his passengers. - the pilot did not mentally prepare himself for this flight
- the aircraft used for the operation was inappropriate for the
task in that the strip at Taggerty was too short for the
combination of aircraft type, its load, and the takeoff procedures
being employed.
The inadequate or absent defences included:
- the company's requirements for pilot currency on type were
inadequate - the pilot's training did not prepare him for this set of
circumstances - the assessment of the pilot's skills during licence renewals
and endorsements were inadequate - the company did not ensure its pilots were complying with the
statutory requirements for weight calculation.
CONCLUSIONS
Findings
- The aircraft had one minor anomaly in one magneto but was
otherwise serviceable for the flight. - The company selected an inappropriate aircraft and an
inadequately prepared pilot to undertake the task. - The pilot was neither experienced nor current on the type.
- The pilot used an incorrect procedure for calculating the
weight and the performance of the aircraft. - The briefings given to the pilot by the chief flying instructor
were inadequate. - Because of the steep authority gradient the pilot was unlikely
to doubt the decisions of the company and the chief flying
instructor.
A Piper Lance and a Piper Cherokee from the same company
departed early in the morning from their base at Albury NSW for
Mount Beauty Vic. At Mt Beauty they were to both pick up a full
complement of passengers for a flight to Taggerty Vic. and to
return later to Mt Beauty. Five of the passengers boarded the Piper
Lance at Mt Beauty and their flight to Taggerty was uneventful.
The aircraft were on the ground at Taggerty for approximately
six hours. Prior to departure from Taggerty the Piper Lance pilot
was briefed by the pilot of the Cherokee, who was the company's
chief flying instructor to select 10 degrees of flap (one notch) in
order to conduct a short field take off. Five passengers boarded
the Piper Lance. The pilot started the engine and taxied after the
Cherokee to the southern end of the 790 metre, grass strip. After
the Cherokee had departed he lined up on the strip, ran the engine
up to full power, checked static RPM and manifold pressure were
satisfactory, then released the brakes.
The pilot said that the aircraft accelerated to 70 knots and
lifted off normally. He said he established a positive rate of
climb at about 80 knots and selected the landing gear and flaps up.
As he was raising the flaps the engine appeared to become sluggish,
climb rate vanished and airspeed reduced. The pilot had to lower
the nose to keep the aircraft flying above the stall speed. The
pilot turned to the left to manoeuvre round a large tree as the
aircraft continued to lose height. The aircraft impacted into a
soggy field some 500 metres from the departure end of the strip. At
impact the aircraft was in a nose high attitude, with the left wing
down and had a high rate of descent. Both main landing gears were
pushed upwards and then dislodged and the nose gear was folded back
into the nose wheel well. The aircraft slid to a stop and the
passengers were able to evacuate suffering only minor injuries. One
passenger went back into the aircraft to assist the pilot to
evacuate.
The passengers advised that the aircraft seemed to accelerate
slowly and lifted off right at the end of the airstrip. They
reported that a warning horn was heard shortly after the aircraft
became airborne and stayed on until the aircraft crashed.
The aircraft
The investigation found that the aircraft was properly
certificated, had been maintained and serviced correctly, held
sufficient fuel for the flight, and had no pre-existing defects
recorded on the maintenance release. At impact the landing gears
were down and the flaps were up. There were no anomalies found with
the airframe and other aircraft systems.
The engine
The engine was examined and, after some minor impact damage had
been repaired, was test run and found to be capable of delivering
full power. One anomaly was found during the post accident
examination and engine run. A blade terminal within the left
magneto was a loose fit and showed signs of minor electrical
arcing.
The pilot
The 23 year old pilot had been involved with the company since
his teenage years. He had completed all of his training with the
company and was currently employed by them, mostly flying twin
engined aircraft. He did not normally fly the Piper Lance, had only
flown a total of 20 hours in the aircraft and, prior to this
day,last flew it for half an hour, 14 weeks prior to this
accident.
Flight preparation
The Piper Lance was not normally used for this operation; it was
replacing a twin engined aircraft which was unserviceable. The
pilot was advised late the previous night by the chief flying
instructor that he was required for the flight, replacing the
normal pilot who had suddenly become unavailable. Due to the late
notification and the early start out of Albury the pilot did not
get time to study the flight manual, nor did he receive a
comprehensive briefing from the chief flying instructor who was
flying the Piper Cherokee aircraft. The chief flying instructor was
part of the ownership and management of the company.
The pilot estimated the take off weight of the aircraft by using
a standard weight of 80 kilograms for each occupant. The statutory
requirements pertaining to takeoff weight calculations require
that, for aircraft carrying seven passengers or less, the actual
weight of each passenger shall be used. The pilot advised that he
had been aware of this requirement during his training some years
before but had forgotten it, and he did not recall it being
mentioned as a part of any licence renewal or aircraft endorsement
checks. By using the standard weight computation the pilot
calculated the takeoff weight to be 1555 kg which included 100 kg
for fuel. After the accident the fuel load was found to be 115 kg.
By utilizing the actual fuel and passenger weights, the takeoff
weight was calculated to be 1629 kg. This made the aircraft 74 kg
heavier than the pilot thought and just 4 kg below its maximum
permitted gross weight of 1633 kg for takeoff. With this loading
the aircraft was outside of the allowable center of gravity
envelope.
The pilot had used the incorrectly calculated lesser takeoff
weight for his estimation of the takeoff distance required. On that
basis he had calculated that he needed 720 metres and therefore the
790 metre strip was adequate. By utilising the correct weights, and
the actual wind and temperature at the time of the accident, the
strip length required was calculated to be 920 metres. This strip
length is what is required for the aircraft to accelerate, lift off
and climb to a height of 50 feet.
The aircraft's Pilots Operating Handbook, which was located in
the glove box of the aircraft after the accident, details two
procedures that can be used for takeoff from short or soft fields.
The first of these is designated the Short Field, Obstacle
Clearance takeoff and requires, for a heavy aircraft:
- the flaps to be set at 25 degrees, the second notch,
- the aircraft to be rotated at 53 knots
- after lift off, gear is selected UP at 58 knots, and
- flaps to be slowly retracted after 87 knots is attained,
and - accelerate to 92 kts, the best flaps up rate of climb
speed.
The second procedure is the Soft Field takeoff with the same
requirements except that the aircraft is to be accelerated to 92
kts before the flaps are slowly retracted.