Unstable Approaches Rampant In Sunday AirVenture
Arrivals
OSHKOSH - A temporarily closed runway and relatively low ceilings caused a
glut of aircraft to arrive into Wittman Airport at the same time Sunday, many of
which flew unstable approaches by traditional metrics.
Ground observers of traffic arriving on Runway 27, one of three "runways"
in operation Sunday afternoon, witnessed numerous close-calls, including would
appear to be one or more near collisions, as a mix of general aviation, business
aviation and "warbirds" funneled into the airport, with the general aviation
aircraft often flying "base" legs at very low altitude before sharply turning 90
degrees to line up with the runway. Typically a stable approach requires the
aircraft to be in landing configuration, speed, glideslope and desired vertical
speed at 500 ft. above the runway.
"I've flown into Oshkosh on a Sunday afternoon for 20 years, and it's the
worst I've ever seen," says Avidyne president Dan Schwinn of his arrival to
Wittman as traffic recovered from an early afternoon landing incident in which
the gear of a Mooney appeared to collapse after a bounced landing.
Runway 27 was closed for approximately one hour. Meanwhile, air traffic
controllers advised inbound aircraft to either fly to an alternate airport or to
hold to be sequenced into the flow of aircraft landing on the North-South
runways (the airport uses a parallel taxiway as the second North-South runway
during the show). "I hope they have a post-mortem to figure out how they got
into it," says Schwinn, a member of the board of directors for the Experimental
Aircraft Association (EAA) who is also involved in industry efforts to stem the
fatal accident rate.
In an environment where loss-of-control (LOC) accidents represent the
majority of fatal accidents for general aviation pilots - and where the FAA,
NTSB and industry are going to great lengths to reduce the numbers, in part by
promoting stabilized approaches - the Oshkosh arrivals stood out as business as
usual.
"I don't think there's ever a time you should be flying close to the ground
in an unstable manner," says George Perry, senior VP for the Aircraft Owners and
Pilots Association Air Safety Institute. He says several of his friends flying
to the airport decided to divert elsewhere when the disruptions occurred on
Sunday. Perry has been a vocal supporter of a circular approach, similar to what
is used by the military, where aircraft are configured near or fully for landing
on the downwind leg, and perform a gentle 180-degree turn to the runway. "If the
aircraft is not on the stabilized approach criteria at 500 ft. above the runway,
the pilot should (perform a go-around)," says Perry. Few pilots on Sunday asked
for go-arounds.
The EAA and the FAA developed a 30-page Notice to Airmen (Notam) that
pilots were encouraged to read before flying into Wittman for the AirVenture
show. The document spells out all the various permutations of arrival scenarios,
encouraging pilots to use other airports if they are "not comfortable with OSH
AirVenture procedures." The Notam also tells pilots not to perform "S-turns"
when trying to maintain 0. 5mi. minimum spacing behind an in-trail aircraft, but
rather to break off the approach and return to the starting point.
Nowhere in the document does the FAA or EAA define an unstable approach or
discuss when to abort an approach. Instead the Notam tells pilots to use "extra
caution" to maintain a safe airspeed and to be "prepared for a combination of
maneuvers that may include a short approach with descending turns, followed by a
touchdown at a point specified by Air Traffic Control (ATC) which may be almost
halfway down the runway." The EAA also points pilots to a Safety Alert that the
NTSB issued for the AirVenture show, cautioning pilots that the "major fly-in
event environment" with "hundreds of thousands of people watching, may create
pressure for pilots to continue an approach that they are uncomfortable with
rather than go around."
That advice is based in part on a stall-spin LOC accident at last year's
AirVenture of a Piper Malibu turning base leg to final on Runway 27 at less than
200 ft. above the ground. The NTSB in its analysis of the accident found that
the controllers had provided the proper clearance between the Malibu and a
departing aircraft on the same runway (the FAA has a waiver to reduce the
minimum horizontal spacing over the runway to 1,500 ft. for the show compared to
the normal 3,000 ft.), but that the pilot did not perform a go-around despite
the unstable approach.
Based on its analysis, NTSB investigators asked the EAA and FAA to insert
comments in this year's Notam about the reduced separation for the show to
inform pilots "not be afraid to ask to go-around," says Scott Dunham, an NTSB
national resource specialist for ATC. NTSB's recommendation to expand the
landing pattern with a wider downwind leg to give pilots more time on the base
leg was rejected since controllers would have difficulty spotting the aircraft
visually, says Dunham. Given the congestion at the airport, controllers, all of
whom are volunteers, visually spot aircraft using binoculars from various
locations on and around the airport. Dunham says there are approximately 86
controllers at the show, most of whom are highly experienced. "It takes four
years to be fully qualified to work here," he says.
This year's Notam alerts pilots to the reduced separation standards and
tells pilots to "notify ATC immediately" if a go-around is needed, but does not
discuss go-arounds in relation to unstabilized approaches. Dunham says there are
a variety of reviews during and after the show to improve the safety of
operations here.
Earl Weener, the NTSB board member who most closely follows the
loss-of-control issues for general aviation, told Aviation Week that pilots must
be prepared "for something unexpected" when operating here during the show, a
key reason for reading the NTSB's safety alert and the Notam beforehand. Weener
flew here commercially this year, but has flown his Bonanza to Oshkosh several
times in the past.
"It's the way Oshkosh has been done for years," he says of the reduced
separation standards and high intensity operations. "There's some degree of
acceptance of the uniqueness of the approach."
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