Safety Pilot Landmark Accident: I think we’re alone now

Two aircraft collide on intersecting runways

June 1, 2010

It is often the flimsiest circumstances that bring two aircraft together. This non-fatal mishap is not the usual VFR-into-IMC, descent-below- minimums, midair collision, thunderstorm, or icing-related accident, but rather a series of relatively common events that by themselves meant little. Collectively, they turned into an accident where a casual omission—and perhaps assumptions by both pilots—was just enough to tip the scales. For both VFR and IFR pilots, the circumstances described here occur dozens of times daily around the country.

On the approach

A Piper Twin Comanche, N7660Z, was inbound to North Central State Airport (SFZ) in Pawtucket, Rhode Island, on June 6, 2008. North Central State is a nontowered airport. The flight had originated from Nantucket, Massachusetts, under instrument flight rules. The 5:35 p.m. recorded weather at North Central State reported calm winds, visibility 10 miles, a 600-foot overcast, and a 3-degree spread between temperature and dew point.

At 5:18:56 p.m. the Piper contacted Providence (Rhode Island) Approach, requesting the GPS Alpha approach to North Central State. Eleven minutes later Bonanza N27199 contacted Providence clearance delivery while on the ground at North Central State for an IFR flight to Morristown, New Jersey. The pilot was given his clearance and told to hold for release. (This is standard ATC procedure that generally allows either the pilot or ATC to finish a checklist or to resolve a conflict.)

At 5:35:44 p.m., Providence Approach cleared the Piper for the approach and one minute later, the pilot was advised to report cancellation of “IFR in the air on this frequency or on the ground on One-Two-Four-Point-Three-Five. Change to advisory frequency approved,” which the pilot acknowledged.

At 5:37:43 p.m. the Beech pilot transmitted the following to Providence clearance delivery: “Providence, Bonanza Two-Seven-One-Nine-Nine, now we’re holding next to Runway Five, ready to go [just need a release].” At 5:37:57 p.m., Providence clearance responded, “Calling clearance was that November Two-Seven-One-Nine-Nine?” and the Beech pilot responded, “Yes, ma’am, we’re holding at Runway Five for departure, One-Nine-Nine.”

A few seconds later, clearance delivery told the Beech pilot, “November One-Nine-Nine, hold for release—I’ll get back to you in approximately five minutes.” The Beech pilot responded, “One-Nine-Nine.” Clearance delivery called back at 5:38:11 p.m., “November One-Nine-Nine, verify holding for release please,” and three seconds later the Beech pilot responded, “We’re holding for release ma’am, One-Nine-Nine.”

At 5:41:49 p.m., the Piper pilot cancelled his IFR flight plan, and then followed with another transmission that he had the airport in sight. Providence Approach responded, “Understand canceling IFR, November Six-Zero-Yankee, roger and squawk VFR, frequency change approved, good night.” The Piper pilot acknowledged, and that was the last recorded transmission from the Piper.

One minute after the Piper cancelled IFR, clearance delivery released the Bonanza for departure, with a clearance void time of five minutes. After receiving his departure clearance, the Beech pilot switched his radio to the common traffic advisory frequency, and broadcast his position and intentions twice, as confirmed by several witnesses. As the Beech pilot began his takeoff roll on Runway 5, the Piper was landing on Runway 15.

According to the Piper pilot, as he approached the intersection of Runway 5/23 at approximately 40 knots, he heard a noise, and saw the Beech on its takeoff roll. The Bonanza was approaching its rotation speed of 75 knots when the pilot and passenger noticed the Piper on rollout, approaching them from their left. The Beech pilot pulled back on the yoke in an attempt to fly over the Piper, and reached an altitude of about six feet before the airplanes collided.

After the collision the Bonanza settled back to the ground, veered off the runway, and came to a stop in the grass. The Piper came to rest facing the opposite direction of travel, approximately 200 feet south of the Runway 5 centerline, and approximately 20 feet off the pavement of Runway 15. Both pilots reported being unaware that another aircraft was operating at the airport until seconds prior to the collision.

The airport

According to the NTSB, “The departure area for Runway 5 and the touchdown zone for Runway 15 were separated by trees that varied in height from approximately 13 to 55 feet. The locations and heights of some of these trees were such that it impeded the ability of the pilots to see one another from their respective runways.” This makes for a really tough environment to see and avoid. Radio communication under these circumstances is perhaps the only way to ensure a clear runway. Obviously, all IFR aircraft must have good communication equipment, so a NORDO aircraft would be unlikely—but not impossible—operating VFR in Class G airspace.

Pilots and aircraft

The 54-year-old Bonanza pilot held a private pilot certificate with an instrument rating. His medical was current and he reported total flight experience of 1,640 hours, 1,000 hours in the accident airplane, and 450 hours in instrument meteorological conditions. In the 90 days preceding the accident, the pilot had flown 11 hours with three hours in instrument conditions.

The Piper pilot, age 45, held a single-engine commercial certificate with an instrument rating and private pilot privileges for multiengine land. At the time of the accident, he had a total of 3,215 hours with 2,000 hours in the accident airplane model, and 418 hours of flight time in instrument meteorological conditions. In the 90 days preceding the accident, the pilot flown 62 total hours, including seven hours under IMC.

Neither aircraft had a traffic alerting system and there was no indication of any mechanical failure aboard either aircraft.

FAA guidance and ATC’s role

The FAA’s Instrument Flying Handbook provides guidance for nonradar environments where pilots are expected to use the CTAF to increase awareness and minimize conflicts. That includes both transmissions and a listening watch. Inbound IFR flights arriving at a nontowered airport should make, at a minimum, a call at the final approach fix and on short final.

Controllers are advised in their handbook to “issue traffic advisories to those aircraft on your frequency when in your judgment their proximity warrants it.” It could have been as simple as “Be advised, there’s a Piper Comanche inbound on the approach that just terminated IFR.”

Probable cause

“Both pilots’ failure to see and avoid the other airplane. Contributing to the accident was the air traffic controller’s failure to notify either pilot of the potential conflict,” concluded the NTSB. In my opinion, the airport environment with trees blocking the view of the crossing runways was also a contributing factor.

Analysis

This accident is eerily reminiscent of a 1996 collision at Quincy, Illinois, between a Beech 1900 and a King Air (“Safety Pilot: Decision at Quincy,” December 1997 AOPA Pilot). The landing 1900 collided with a King Air whose pilot neither looked nor communicated that he was taking off on a crossing runway. All aboard both aircraft were lost in the post-crash fire. In both this Rhode Island accident and the one in Quincy, one aircraft was on the CTAF, while the other was apparently not listening or looking.

It’s easy to get complacent at less-busy airports, believing that you are alone. It’s comforting to think that ATC has your back—and most of the time that’s true. The danger comes when we relax too much. Using football terminology, perhaps there were offsetting penalties for both pilots. The landing Comanche had the right of way but failed to announce his position on CTAF. The Bonanza pilot made the proper calls but failed to see the inbound Piper on the crossing runway. Intersecting runways make life easier in crosswinds but greatly increase the collision potential, especially if the ends of the runways are not visible.

Transitioning from IMC to VFR in the Class G airspace puts additional burdens on pilots. We’re letting down from the instrument approach, configuring the aircraft, and a circle-to-land increases the workload. Arriving IFR aircraft often have a low level of VFR or airport situational awareness because often they’re only on the frequency a short time after leaving ATC.

Departing pilots under the same weather conditions are often thinking ahead to the high workload during an IMC departure, making sure all the avionics are properly set, and busy with the takeoff. It’s good to query ATC whether there are any inbounds, but who has time to be looking or thinking about other aircraft? “I think we’re alone now; there doesn’t seem to be anyone around.” Don’t bet on it!