History of Flight
The Mooney M20C departed Penticton Airport from runway 16 at 1052 Pacific daylight time on a local visual flight rules sightseeing flight with the pilot and three passengers. At 1127, the pilot re-established communications with the Penticton flight service station (FSS) on the mandatory frequency, reporting east of the airport at 5500 feet inbound. The FSS issued an advisory that runway 34 was preferred, which the pilot acknowledged. At 1130, the pilot advised proceeding northwest toward Naramata (8 nautical miles north) for descent. At 1133, he reported by Naramata, and about one minute later, he advised proceeding south along the west side of Okanagan Lake toward Penticton.
Meanwhile, a Cessna 177RG with only the pilot on board taxied out for a visual flight rules departure to Valemount. The pilot advised the Penticton FSS he was ready to depart; the departure time was recorded as 1135. At about 1136, the two aircraft collided in-flight approximately 0.9 nautical mile from the departure end of runway 34. Both aircraft were destroyed and crashed within the city of Penticton. All five occupants were fatally injured; no other injuries occurred.
Communication and Circuit Procedures
The Mooney pilot's check-in call was incomplete: it did not include altitude, intended arrival procedure, or estimated time to landing. The pilot stated he would remain west of "the track," an ambiguous term not standard in radio communications. The FSS specialist interpreted this as remaining west of the extended runway centreline, concluding the Mooney would join the circuit midfield and not conflict with the departing Cessna. However, the Mooney followed a path at approximately 45° to the downwind leg, crossing through the departure path of runway 34 at an estimated altitude between 500 and 700 feet above ground level, below the standard circuit-joining height of 1000 feet above aerodrome elevation.
The Cessna pilot made four radio transmissions regarding his departure. It was not determined if the Mooney pilot heard any of these. No transmission was directed to the Mooney to advise of the departing Cessna. The Cessna pilot had been advised of the inbound Mooney during the initial airport advisory and, based on subsequent Mooney transmissions indicating a route along the west shore and intention to report right-hand downwind, would have expected the Mooney to follow standard circuit-joining procedures—remaining west and crossing over the airport before joining downwind. The Cessna's flight path was consistent with a straight-out climb on runway heading (340° magnetic) as per standard departure procedures.
FSS Advisory Services
The Penticton FSS provided an airport advisory when the Cessna pilot initially contacted them. When the pilot reported ready for takeoff, no traffic update was given. According to FSS MANOPS, another advisory is not required unless the specialist believes traffic is pertinent or a potential conflict exists. The specialist knew an aircraft was inbound but had not established visual contact and had no independent means to detect the Mooney's unexpected turn east. The specialist's situational awareness relied on the mental picture formed from radio reports and the expectation that pilots would follow recommended procedures. The Mooney's intended circuit-joining procedure was never provided or requested, and the FSS did not ask for clarification.
Aircraft and Weather
No mechanical defect was found in either aircraft. At the time of the accident, the weather was sunny with unrestricted visibility, little cloud, and calm wind.