http://www.saflyermag.comfirst light the following morning. It was
strewn over a hundred meters along the
Mogul River. Chris and the farmer had been
killed on impact. Wire was wrapped tightly
in a bundle around the tail rotor gearbox
and drive shaft, and the tail rotor blades had
been sheered. Chris had no doubt been
relaxed after a hard day’s flying, and in the
failing light had not seen the wire cable
strung across the river.
Low level flying that is conducted
anywhere from a few feet above ground to
somewhere between the big trees is not for
everyone. But this is the domain of many
professionals, from crop dusting, fire-
fighting, and game work to EMS operations.
During such tasks the concentration
required by the pilot is intense and there is
a possibility that the helicopter may collide
with obstacles. It’s a wonder that there are
not more accidents.
I think that while we are actually
‘working’ in such hostile environments, our
awareness is heightened and we tend to
hyper-focus. All too often low level flying
accidents as a result of a collision with
wires occur off duty, ferrying or simply
while relaxing on the way back to base.
The danger is common to all of us who fly
low. Collisions with wires do not constitute
a SPECIAL RISK for SPECIAL PILOTS.
Many pilots and aircraft need to have the
dust brushed off them prior to their working
season. But there are several groups of
pilots that could use some extra special
care.
Because of their unique operating
environments, fire-fighting, helicopter, and
agriculture pilots deserve special attention
when getting ready for a new operating
season, especially if they haven’t flown
much over the summer holidays. Some
pilots are lucky, as they live or work in areas
of the country where they can maintain their
currency year round, but for those pilots
who have to lie low over the off season, the
following should serve as a reminder that
low level helicopter flying requires a high
level of proficiency.
A recent US Air Force study examined
pilots’ visual scan patterns during a
simulated high-speed, low-level flight
and how their scan rates related to flight
performance. As helicopters become faster
and more agile, pilots are required and
tempted to navigate at low altitudes while
traveling at high speeds. A pilot’s ability to
interpret information from a combination of
visual sources determines, not only mission
success, but also aircraft and crew survival.
In a fixed-base helicopter simulator
modelled after the US Navy’s MH-60S,
17 active-duty Navy helicopter pilots with
varying total flight times flew through a
simulated southern Californian desert
course. Pilots’ scan rate and fixation
locations were monitored using an eye-
tracking system while they flew through
the course. Flight parameters, including
altitude, were recorded using the simulator’s
recording system.Experienced pilots with more than
1,000 total flight hours better maintained a
constant altitude (mean altitude deviation
= 48.52 feet, SD = 31.78) than less
experienced pilots (mean altitude deviation
= 73.03 feet, SD = 10.61) and differed in
some aspects of their visual scans. Theyspent more time looking at the instrument
display and less time looking out of the
window (OTW) than less experienced pilots.
Looking OTW was associated with less
consistency in maintaining altitude. Although
interesting, this is all fine and well for
instrument flying but does not really help the
VFR pilot, who should never fly lower than
the expected height of power lines.Helicopters also share another special
operating risk that fixed-wing aircraft
don’t normally share: frequent off-airport
operations. Many Alaskan and other fixed-
wing pilots routinely operate off-airports,
particularly those in more remote areas, but
the majority of fixed-wing pilots operate offLow level flight climbing up a
valley is a recipe for disaster
since power lines are often strung
invisibly across the valley.All too often low level
flying accidents as a result
of a collision with wires
occur off duty, ferrying or
simply while relaxing on
the way back to base.