Powerline markings and aerodrome information.
The aircraft, a PA 38-112 Tomahawk, was on final approach for a
landing at Torquay (Vic.) ALA when it struck powerlines. The
aircraft suffered significant damage from the powerlines and
further damage from the impact with the ground. The pilot and his
passenger (also a pilot) were not harmed.
AERODROME MARKINGS: The Torquay airport operator had placed
displaced landing threshold markers some way into the landing strip
of runway 18 to establish a safe approach gradient over the
powerlines. These markers were painted white, as were the runway
edge markers, which extended the full length of the runway surface.
The colouring of the airfield surface, at the end of a hot dry
summer, did not provide adequate contrast to allow the pilot to see
the white landing threshold markers against the dry grassed surface
of the runway. The aerodrome was marked correctly, however, the
local dry conditions contributed to the accident by preventing easy
identification of the displaced threshold.
AERODROME INFORMATION: The Aircraft Owners and Pilots Association
(AOPA) Airports Directory contains information supplied by the
aerodrome operator on a survey form supplied by AOPA. That survey
form does not follow the example on page 55 of the Airservices
Australia publication, the Enroute Supplement Australia, in that it
does not list any examples of hazards that need to be considered.
An airport owner may not consider relevant or cover all the hazards
associated with the aerodrome unless there was just such a list to
refer to. The information published for Torquay did not mention
powerlines or any displaced landing thresholds.
Before departing for Torquay the pilot had studied the AOPA
airfield directory and phoned the operator for approval to land. He
also asked about local conditions and was informed of parachute
operations that day. The pilot did not ask, nor was he told about
any powerlines or displaced thresholds. The pilot and his passenger
were familiar with the runway layout having flown over the
aerodrome previously, however neither had landed at the aerodrome.
Approaching Torquay they had heard another aircraft broadcast that
it was landing on runway 18 so they joined crosswind for that
runway, noting as they flew overhead the worn take-off threshold
area adjacent to the fence.
The pilot followed the correct procedure by telephoning the airport
prior to departure, however when questioned later by the
investigator, the operator advised that he had not brought the
power line or the displaced threshold to the attention of the
pilot. Also, the operator later advised that the correct details
and a diagram could be found in the other private airfield
directory, the Country Airstrips Guide. He did not check which
guide the pilot was using.
The Enroute Supplement lists items to be covered by pilots before a
safe operation can be conducted into an unfamiliar aerodrome.
Listed below are the specific obstacles, hazards and special
procedures used as examples in ERSA, along with further items that
may need to be considered (this list is by no means meant to be
Obstacles: - Powerlines, trees, buildings, terrain, roads,
railways, fences, windmills, towers and masts etc.
Hazards:- Turbulence, updraughts, downdraughts, livestock, birds,
wildlife, long dry/wet grass, effect of recent rain (e.g. washouts
or soft spots), ditches, drains, earth mounds, tree stumps,
vehicles, anthills, animal burrows, non-standard markings, rough
areas and obstacles hidden by long grass etc.
Special Procedures:- Circuit direction, noise sensitive areas (eg
cattle yards or homes), sport aviation and displaced thresholds
- Powerlines in the vicinity of some aerodromes and landing areas
are not adequately marked.
- Under some conditions, aerodrome colouring can make runway
markers difficult to distinguish, particularly if the pilot is
unaware of displaced thresholds.
- A pilot that does not have access to detailed information
regarding local conditions may not be able to conduct safe
operations into an unfamiliar aerodrome.