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wing-mounted engines to more than 200 feet
behind some larger aircraft. Within this area, jet engines
can generate hurricane-level exhaust forces approaching
100 knots.
The potentially dire results? Before a crew can say
“powerback,” jet engine blast can up-root trees, flatten
building structures, shatter windows, lift and propel
heavy objects, weathercock braked airplanes, blow over
lift trucks, shift unbraked baggage carts, and create
other havoc on airport ramps, taxiways, and runways.
Although the diagrams don’t say so, jet blast can also
injure or kill crew and passengers who happen to cross
its path.
The fact that few serious jet blast incidents and accidents
occur during millions of ground operations annually
is a tribute to the training and professionalism of
air carrier flight and ground crews, and to the continual
care they exercise in ground operations. When we looked
at ASRS data, we found that ground jet blast incidents
(fifty-one reports) represented only a tiny fraction of the
total incidents reported. Yet even this small number of
jet blast reports contained some surprises:
Issue Number 6 5
Table 1 — Site Of Jet Blast Incident
Site of Incident No. Rpts. % Data
Ramp 27 53
Taxiway 10 20
Runway (Hold, Landing, Takeoff) 10 20
Runup Area 4 7
Total 51 100%
& Almost half of the jet blast incidents reported to
ASRS occurred on taxiways, in run-up areas, and
adjacent to or on runways—all relatively
uncongested airport areas. The other half occurred
on ramps, where many more such incidents might
be expected because of close aircraft parking and
tight maneuvering conditions;
& Incidents of jet blast damage that occurred on ramps
were invariably associated with sharp turns of the
aircraft during an engines-on pushback, powerback,
taxi-out, or taxi into a gate. Use of a tug or tractor
did not prevent such incidents if the aircraft was
turned sharply during the pushback or taxi-in maneuver;
& Eighty-five percent of the damage inflicted by jet
blast was to the wings, props, flaps, and rudders of
other aircraft, especially to light aircraft weighing
five-thousand pounds or less. Eleven percent of the
damage incidents involved building structures, objects,
or vehicles. Injuries to people accounted for
four percent of the jet blast damage total.
What are the lessons to be learned from these ASRS jet
blast incidents? We begin by briefly revisiting the sites
where almost half the jet blast incidents reported to
ASRS occurred—taxiways, runup areas, and areas on
or immediately adjoining runways.
Taxiways and Runways: Aim Prevents Blame
Collectively, off-ramp sites accounted for forty-seven
percent of the jet blast incidents reported to ASRS.
These off-ramp locations were taxiways; areas on or
immediately adjoining runways, and run-up areas .
(See Table 1, below.)
The usual targets of jet blast in these locations were
light aircraft weighing 5,000 pounds or less, that were
unexpectedly crunched and pummeled by the blast
forces from jet engines. Frequently, the jet blast damage
was the result of misdirected engine run-ups and
tests. This pilot’s experience was typical, down to the
inevitable details of a prop strike and bent wing:
✍ “…We taxied out and followed the taxiway east
then turned southbound…After the turn had been
completed, I felt the airplane being lifted from the
tail and forced over to the right side. The nose, prop,
and right wing struck the ground, then we started to
be pushed along the taxiway in that position…It was
not until I was outside of the airplane that I realized
that we had been overturned by an air carrier jet that
was doing a runup facing the blast fence with the jet
blast directed toward the taxiway…I was told that
the occupants of the jet were all maintenance [personnel]…”
(ACN 226055)
Heavier aircraft were also susceptible to jet blast damage
in these locations. In an incident reported by two
different flight crews, a small transport aircraft (in the
5,000 to 14,500 pound weight category) played “chicken”
with a widebody aircraft holding in position on a runway
for a nighttime takeoff—and lost. The sense of
helplessness experienced by the pilot of the small transport
came through clearly in his report to ASRS:
✍ “The widebody was sitting in position and was
not rolling and I felt I could cross behind him and taxi
to park. I pushed up the power to cross and about
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