Accident Analysis

One of the most arcane arguments about flying traffic patterns at nontowered airports centers on whether the specified procedures are "regulatory" or "advisory." The debate goes something like this: Left turns are regulatory, absent any published nonstandard pattern; flying a right-hand pattern without good reason is a clear sign of a bad aeronautical upbringing, and may even justify sending the pilot to reform school.

But the recommended pattern legs and altitudes illustrated in the Aeronautical Information Manual and normally taught and flown by most pilots are merely "advisory." And this, if true, leaves you without a leg to stand on when debating whether to twit that other pilot about the straight-in approach that he just made, causing you to go around because either he cut you off, or you could not see him. If you are still moved by pique or moral indignation to confront him, base your comments on right-of-way regulations, or that one which decrees, "No person may operate an aircraft so close to another aircraft as to create a collision hazard." But leave out the part about the straight-in approach. It's immaterial, if not entirely irrelevant from a see-and-avoid perspective. Thank him for giving you the chance to practice your balked-landing skills in advance of your next flight review - and leave it at that.

Failure to see and avoid, sometimes caused by conflicting traffic patterns or unexpected maneuvering, occasionally results in midair collisions, and accident reports glaringly underscore the avoidability of even these rare events. Of the 1,494 total fixed-wing general aviation accidents in 2001, there were only five midair collisions. Three were fatal to a total of eight people. In 2000, there were 19 midairs resulting in 32 fatalities, according to the AOPA Air Safety Foundation's recently released 2002 Nall Report on accident trends and factors. "Midair collisions usually occur on good VFR days, at low altitude, close to airports. In 2001, all of the midair collisions occurred in [visual meteorological conditions] and during the hours of daylight," the report noted. Over the long term, only 5 percent of midairs were of the typically envisioned, head-on variety. Eighty-two percent arose from a faster aircraft overtaking a slower one; 78 percent of airport-area midairs occurred at nontowered airports.

Two midairs that occurred within four days of each other in August 2000 and another that happened in August 1998 bring the focus back to the debate on traffic pattern operations at nontowered airports. None was fatal, thanks to their occurrence at low altitude in the final approach area. The midair on August 11, 2000, involved a Cessna 150 and a Stinson AT-19 that collided on the final approach to Runway 35 at Coronado Airport in Albuquerque, New Mexico. The commercial pilot in the Cessna and the ATP flying the Stinson were on local flights and suffered only minor injuries.

"The Stinson pilot told the FAA inspector that he flew one approach to a landing at Coronado Airport, but had to go around due to an airplane on the runway. The pilot said that he flew a second traffic pattern and again an airplane took the active runway in front of him. A witness observed the Stinson turn to the east [that is, to the right], at 100 to 250 feet above the ground, and disappear for a short time period, and then reappear turning right onto a short final. Another witness reported that the Stinson performed a 'low-level 360-degree turn.' The Stinson pilot did not report any deviations from a standard left traffic pattern," according to the National Transportation Safety Board report. The Stinson pilot also reported that during the flight his handheld transceiver had apparently failed, and no witnesses reported hearing him transmit over the common traffic advisory frequency.

"The pilot of the Cessna said that he departed Coronado Airport at 8:45 for local air work. When he entered the traffic pattern for a full-stop landing, witnesses reported that they heard the Cessna pilot transmit his position and intentions on the common traffic advisory frequency. The pilot reported that while on final, he 'settled' down onto the Stinson during the landing flare," the report continued. The NTSB paraphrased both the "recommended" and regulatory guidance available to pilots arriving at nontowered airports: "The AIM states that, unless otherwise indicated, all VFR traffic patterns are a rectangular box with left-hand turns. Federal Aviation Regulation Part 91.113 and the AIM state that a VFR missed approach to a landing are flown down the runway or in such a manner so as not to fly over an airplane on the runway." The NTSB described the accident's probable cause as "the failure of both pilots to maintain visual lookout. A contributing factor was the pilot not following recommended traffic pattern procedures." (See "Legal Briefing: See and avoid," p. 69.)

Similar comments, although based on other official sources of information about how to fly a traffic pattern, appeared in an accident report generated by a collision of two agricultural aircraft, an Air Tractor AT-502 and a Schweizer G-164B, four days later at an airport near Deerpark, Louisiana. "The Air Tractor was on a straight-in approach for a north landing. The Schweizer had made a base leg from the west over high power lines and trees for a north landing. The Air Tractor was about 60 feet agl when the Schweizer impacted the top of its fuselage, aft of the cockpit. Both airplanes impacted the ground together about a quarter-mile short of the runway. A fire destroyed both airplanes," said the NTSB. It observed that "FAA AC 90-66A, 'Recommended Standard Traffic Patterns and Practices for Aeronautical Operations at Airports Without Operating Control Towers,' states in paragraph 8(c) that 'arriving aircraft should be at the appropriate traffic pattern altitude before entering the traffic pattern. Entry to the downwind leg should be at a 45-degree angle abeam the midpoint of the runway.'" The report added that "the operator reported that communication at the privately owned airport is by FM radio. The Air Tractor was not equipped with an FM radio."

Does the officially determined cause of this mishap sound familiar? It was "The failure of both pilots to maintain a visual outlook during landing approach. A con- tributing factor was both pilots' failure to follow recommended traffic patterns."

While the discussion rages over the recommended patterns and regulatory procedures, a large contingent defends another common practice and awaits an official response to the query, What about crosswind arrivals? Should a pilot arriving from the east for a north landing (with left turns in the pattern) have to fly well beyond the pattern to the west of the airport, and then descend and turn onto the recommended 45-degree downwind? What is wrong with the midfield crosswind-to-downwind technique used by many pilots and taught for decades?

An accident involving an aerobatic Yak 55M aircraft making such a pattern entry and a Cessna 172 in Lincoln, California, on August 1, 1998, was attributed to "inadequate visual lookout," but conspicuously absent from the NTSB findings was criticism of the traffic pattern flown.

One sure lesson from the mishap, however, is to be sure that the aircraft you are following is the only aircraft that you need to worry about in a busy place. "As he overflew the runway he heard an aircraft call on final approach for Runway 15 over the CTAF. He observed an aircraft on a one-half-mile final and followed that aircraft on a short turning base-to-final approach. As he rolled out on final and prepared to flare, he felt the collision with an unseen aircraft. The pilot of the Cessna 172 stated that he was in the traffic pattern practicing takeoffs and landings. He said that he called on the CTAF number three for landing behind a Cessna 150 and extended his pattern slightly to allow time for that aircraft to clear the runway. The pilot reported that he announced his position while on base and final approach. Just as he was flaring the aircraft, he felt a jolt and the aircraft was forced down onto the runway." Another Cessna 150 in the pattern reported that the Yak cut him off when turning from the crosswind to downwind, and the two aircraft nearly collided. Fortunately there were no injuries in this on-the-runway collision in a bustling airport traffic pattern.

True to the 2002 Nall Report analysis, all these events occurred at low altitude, near airports, during daylight, and in good weather. With the stage thus set, it took an added combination of nonstandard arrivals, malfunctioning radios, extended traffic patterns, and unpredictable altitudes to complete the accident-event chain. Don't be "dead right," basking in complacency, as you pride yourself on your perfect, textbook arrival at a nontowered airport. Check the pattern carefully, and then scan all those "wrong" parts of the sky before concluding that the coast is clear.

Dan Namowitz is an aviation writer and flight instructor. A pilot for 19 years and an instructor for 13, he enjoys learning to fly "anything new and different."