SEA97FA105

The pilot of the Cessna 182, N5434B, called departing as a flight of two behind the Piper PA-28R-200, N5270T, and was cleared by tower to depart as a flight of two. The passenger in the Piper reported that shortly before the two aircraft collided, he observed the high-wing Cessna 45 degrees aft and right of the low-wing Piper, well low, but then lost sight of the Cessna and did not regain sight of it before the collision. The line of sight from the Cessna to the sun just before the collision was computed to be approximately at the Cessna's 9:30 position, 65 degrees above the horizon, with the line of sight from the Cessna to the Piper at about the Cessna's 10:30 position and well high. The Piper pilot reported that at the time of the collision, he was looking at opposite direction traffic in front of and above the Piper. The Cessna's empennage separated and the Cessna crashed. The Piper was able to return to the departure airport and land. The Piper pilot reported that the Cessna pilot made no prior arrangements with him to fly in formation.

History of flight

On May 10, 1997, approximately 1242 mountain daylight time, a Cessna 182, N5434B, collided in midair with a Piper PA-28R-200, N5270T, near Clinton, Utah. The Cessna subsequently impacted terrain and was destroyed, and its three occupants, consisting of a commercial pilot-in-command and two passengers, were killed. The Piper was able to return to Ogden Municipal/Hinckley Airport, Ogden, Utah, and land successfully. The private pilot-in-command and a pilot-rated passenger (who owned the Cessna) in the Piper were uninjured, but the Piper was substantially damaged in the collision. Both airplanes were en route from Ogden to Salt Lake City, Utah, and were operating under 14 CFR 91 at the time of the collision. Visual meteorological conditions prevailed, and neither aircraft had filed a flight plan.

The five aircraft occupants had flown separately in the two involved aircraft from Salt Lake City to Ogden for a social engagement together, and were returning to Salt Lake City at the time of the occurrence. Recordings of the ground control and tower frequencies at Ogden showed that shortly after N5270T received taxi instructions and its pilot requested a departure "out west around the lake", the pilot of N5434B called for taxi. The ground controller asked for N5434B's requested departure routing and was told, "we will go over [Antelope] island same as these guys...in fact we'll make that a flight of two." (Antelope Island is a predominantly north-south oriented island, approximately 13 nautical miles long, in the Great Salt Lake; its northern end is approximately 13 nautical miles southwest of the Ogden airport.) The Ogden control tower tape also showed that just after N5270T had been cleared for takeoff with a direction of flight toward Antelope Island, the pilot of N5434B called that he was departing as a flight of two, and was cleared to take off as a flight of two. Ogden air traffic control (ATC) personnel stated in a post-accident interview with investigators that the two airplanes took off on runway 16 with about 2,000 feet of separation. Following the takeoff of the two aircraft, the Ogden tower controller initially suggested a turn to N5270T "of no more than...two ten to like...runway heading", to avoid another aircraft on an instrument landing system (ILS) final approach to Ogden runway 3.

Both the pilot and passenger of the Piper stated that they observed the Cessna on one occasion after takeoff. The pilot described the Cessna's position at the time he observed it to be to the right of his aircraft, slightly behind, and slightly high. The passenger described the Cessna's position at the time of his observation as behind (about 45 degrees aft) and to the right of the Piper, and well low. The passenger, who was sitting on the right side of the low-wing Piper, stated that he subsequently lost sight of the high-wing Cessna, and attempted to regain sight of it but did not see it again before the two planes collided despite looking for it continuously until the collision.

Approximately two minutes before the crash, Ogden Tower called traffic to the pilot of the Piper, consisting of a flight of two skywriting aircraft en route to an operating area between Ogden airport and Hill Air Force Base (approximately 4 nautical miles south-southeast of the Ogden airport.) The controller told the pilot of N5270T that the flight of two skywriting aircraft was at twelve o'clock (directly in front of the Piper) at one and one-half miles, flying in the opposite direction to the Piper, at 6,200 feet above sea level. The Piper at this time, according to ATC records, was at 5,400 feet above sea level (approximately 1,000 feet above ground level in that area.) The pilot of the Piper stated in an initial interview that he was looking at the flight of skywriting aircraft, directly in front of and above him, when he felt a "thump" from underneath his aircraft. The Piper pilot stated that he was flying straight and level at the time this occurred. The passenger in the Piper subsequently observed the Cessna in a descent for a brief interval before it impacted the ground. He stated that the Cessna descended "straight down."

Several witnesses to the accident reported to Sunset, Utah, police that immediately prior to the collision, the Cessna moved to a position below the Piper and then pulled up sharply, with the collision ensuing. The witnesses stated that when the aircraft collided, they saw pieces separate from the Cessna (which piece or pieces separated varied among the different witness accounts) and the Cessna then fell to earth, exploding and burning upon ground impact.

The accident occurred during the hours of daylight at approximately 41 degrees 7.8 minutes North and 112 degrees 5.7 minutes West. According to a plot of the crash site coordinates made on the Salt Lake City VFR Terminal Area Chart, the Cessna crash site underlies Class E airspace with a floor of 700 feet above ground level (AGL), and is approximately 1 nautical mile outside the lateral boundary of Ogden's Class D airspace area.

Aircraft information

According to the 1956 Cessna 182 owner's manual, normal climb airspeed for the Cessna 182 is 100 to 120 MPH. Normal cruise airspeed for the type at 5,000 feet above sea level ranges from 143 MPH true airspeed at 57% power to 162 MPH true airspeed at 78% power. The aircraft's best rate of climb airspeed under standard atmospheric conditions and maximum gross weight is 85 to 86 MPH indicated airspeed (approximately 92 MPH true airspeed under standard atmospheric conditions at 5,000 feet), with a climb rate of 950 feet per minute. Based on mathematical relationships, the combination of a true airspeed of 92 MPH and climb rate of 950 feet per minute corresponds to a climbing flight path angle of 6.7 degrees above the horizontal.

According to the PA-28R-200 pilot's operating handbook, recommended enroute climb airspeed for the PA-28R-200 is 110 MPH. True airspeed at 5,000 feet density altitude ranges from 138 MPH at 55% power to 162 MPH at 75% power. The aircraft's best rate of climb airspeed with landing gear retracted, at maximum gross weight and 5,000 feet, is 100 MPH (108 MPH true airspeed under standard atmospheric conditions at 5,000 feet), with a climb rate of 630 feet per minute. Based on mathematical relationships, the combination of a true airspeed of 108 MPH and climb rate of 630 feet per minute corresponds to a climbing flight path angle of 3.8 degrees above the horizontal.

Meteorological information

Computed astronomical data indicated that at the time of the accident, the sun's azimuth in the accident area was approximately 160 degrees true and its altitude was approximately 65 degrees above the horizon. Based on this solar position, the direction in which the accident aircraft were heading (approximately 234 degrees true from Ogden-Hinckley Airport to the northern end of Antelope Island), and the Piper passenger's observed position of the Cessna relative to the Piper (about 45 degrees aft, to the right of the Piper, well low) before the accident, the lines of sight from the Cessna to the sun and from the Cessna to the Piper immediately before the accident were computed. The line of sight from the Cessna to the sun was computed to be approximately 286 degrees relative to the Cessna's nose (i.e., at about the Cessna's 9:30 position) and 65 degrees above the horizon, with the line of sight from the Cessna to the Piper being about 315 degrees relative to the Cessna's nose (i.e., at about the Cessna's 10:30 position) and well high.

The cloud cover at Ogden (about 5 1/2 nautical miles northeast of the Cessna main wreckage site) was reported as "few" (one to two-eighths' sky cover) at 15,000 feet above ground level at 1300.

Communications

According to the U.S. Government Airport/Facility Directory (A/FD), Ogden-Hinckley Airport was in a class D airspace area at the time o