Tight spot: Lessons from
the Cory Lidle accident
Accident
Animation
Anyone who’s ever flown a tight traffic pattern knows that most
airplanes don’t turn on a dime. Add a fairly substantial crosswind, and silver
dollar doesn’t even begin to describe the effect on turn diameter. Steepening
the bank helps to a point—but not beyond the point where airspeed and stall
speed become one and the same.
On Oct. 11, 2006, a Cirrus SR20 attempted a tight, 180-degree
turn to reverse course over New York City’s East River. The aircraft drifted
toward Manhattan during the maneuver, crashing into a high-rise apartment
building and falling to the street below. The impact and post-crash fire killed
the two pilots and seriously injured an apartment tenant.
The Cirrus departed nearby Teterboro Airport in Teterboro, N.J.,
about 2:30 p.m. The pilots—New York Yankees pitcher Cory Lidle and his
California-based flight instructor Tyler Stanger—had indicated to friends that
the purpose of the flight was to circle the Statue of Liberty. According to ATC
transcripts, the pilots acknowledged that they were to remain clear of the New
York Class B airspace. The Class B floor ranges from 1,500 to 1,100 feet msl
over the Hudson and East Rivers, located west and east of Manhattan Island,
respectively.
After takeoff, the Cirrus turned southeast toward the Hudson
River, then followed the river past the southern tip of Manhattan to the Statue
of Liberty. The aircraft’s altitude varied from 500 to 700 feet msl throughout
the flight. At 2:36 p.m., after circling the statue, the airplane headed
northeast toward the East River.
As the Cirrus followed the East River northbound past Manhattan,
it approached the end of the river’s Class B exclusion—the airspace equivalent
of a box canyon. Here the Class B floor transitioned from 1,100 feet msl to the
surface, requiring either a 180-degree turn to reverse course or an ATC
clearance to enter the Class B airspace near LaGuardia Airport.
Photo
illustration courtesy NTSB
At about 2:42 p.m., at an altitude of about 600 feet msl, the
pilot began a left turn. During the maneuver, the airplane crossed over
Roosevelt Island, which splits the East River into two channels. Radar data
indicate the turn was only 75 percent complete as the Cirrus approached the
Manhattan shoreline, prompting the pilot to aggressively increase the bank
angle. Witnesses reported that the airplane began losing altitude and its wings
were “wobbling.” The Cirrus pitched down before slamming into the north facade
of a 520-foot-tall apartment building at roughly 330 feet above street level.
Radar analysis revealed that the pilot failed to use the full
width of the river for the turn, beginning instead at a point in the middle of
the East Channel (see graphic). In addition, an easterly wind of 13 knots would
have caused a westward drift of 300 to 400 feet during the maneuver. These
factors combined to reduce the effective available turn width from 2,100 feet
to 1,400 feet. At 97 knots, the airplane’s approximate airspeed, such a turn
would have required a minimum constant bank angle of 50 degrees. At 61 degrees
of bank, however, the wing would stall.
Data indicate most of the turn was actually accomplished at a
bank angle of only 40 to 45 degrees. With the maneuver incomplete and New York’s
skyscrapers looming large, the pilot likely increased the bank beyond the
61-degree threshold, placing the Cirrus into aerodynamic stall while pulling
through the turn. The NTSB determined that the accident’s probable cause was
the pilots’ inadequate planning, judgment, and airmanship in the performance of
a 180-degree turn maneuver inside of a limited turning space.
The pilots could have avoided their fate in several ways. Using
the entire width of the river would have increased the turn diameter. Better
yet, transitioning to the west side of the waterway and turning right—into the
prevailing wind—would have decreased the required bank angle to 35 degrees,
according to the NTSB. Extra altitude also would have helped. Climbing closer
to the Class B floor of 1,100 msl would have placed the airplane above even the
tallest buildings of eastern Manhattan, lessening the urge to aggressively bank
to avoid imminent collision.
Lastly, and perhaps most importantly, if the pilots were
uncomfortable with their chances of safely completing the turn, they could have
contacted ATC and requested clearance to transit the Class B airspace. When
safety of flight is at issue, pilots shouldn’t hesitate to reach out for ATC
assistance.
The likelihood is slim that other pilots will find themselves in
the same tight spot: The East River exclusion has been closed to most
fixed-wing aircraft since the accident, and the FAA is taking steps to make
this temporary flight restriction permanent. But the Cory Lidle accident reinforces
the inherent risk pilots face during maneuvering flight—and the importance of
planning, awareness, and solid airmanship. Bank angles beyond 30 degrees, for
example, have no place in a traffic pattern. Snap decisions and aggressive
efforts to salvage an overshot turn—such as base to final—can put the airplane
at odds with the basic laws of aerodynamics. Unfortunately, when that happens,
the theorems typically triumph.