July 1, 2001
By Bruce Landsberg
Bruce Landsberg flies formation in the production of instructional videos for the Air Safety Foundation.
Watching the Thunderbirds or Blue Angels do the dance in formation is a spectacle to behold. The announcer probably should preface the performance with "Don't try this at home." The pros train for years to develop that skill, and it doesn't always work for them. Amateurs can perform basic formation flight and sometimes get away with it, but the risk is significantly greater than that of solo flight operations.
The AOPA Air Safety Foundation reviewed the years from 1991 through 2000, during which the NTSB recorded 160 midair collisions (see " Ounce of Prevention: Flying a No-Hitter Game," page 117). About 17 percent—or 28 midair collisions—occurred during formation flight. When considering the probable hours spent in formation flight relative to nonformation flight, the numbers are not very encouraging. This includes some airshow collisions, which demonstrates that even the pros can have a bad day. We lost a very seasoned aerobatic team, The French Connection, just last year during a practice session. They had flown together for years before the fatal mishap.
The desire to fly up close and personal is something that most pilots have felt at some time during their flying career, and there are legitimate operational needs for this type of flight. But the margins for error are thin and the outcomes for a botched formation range from minor damage, infrequently, to the loss of both aircraft, more likely. This is an unforgiving environment. Understand the risks and be sure your passengers agree as well.
Flying dissimilar airplanes in difficult environments compounds the problem. A Mitsubishi MU-2 turboprop and a Cessna 310 collided after the pilots decided to fly formation at night. Neither pilot had formal training nor experience in night formation flight. The 310 was in the lead and the MU-2 formed up on the right wing of the Cessna. The MU-2 pilot then advised the Cessna pilot he was going to change sides, and dropped back. The MU-2 went out of control and crashed after hitting the 310 and ripping the right horizontal stabilizer from the empennage. The Cessna's right wing and props were damaged, but it was able to land safely. The tail navigation light was inoperative on the Cessna—a minor detail that was important under the circumstances.
Photo missions create their own problems. A modified Douglas DC-3 and a Beech A36 Bonanza collided during a photo flight, the purpose of which was to get aerial photos of the DC-3. According to the NTSB, "A witness saw the airplanes at 500 feet to 700 feet agl, flying close together, heading north. He said the big plane [the DC-3] was flying straight and level. The little plane then hit the big plane near the middle. After impact, pieces of aircraft were seen falling. Another witness saw the DC-3 heading north and the A36 circling above and below. On its last pass, the A36 circled behind the DC-3, then crossed over, hitting the top of the DC-3. After impact, the DC-3 gently rolled or turned westbound. The left wing then came off, followed by the right wing about two seconds later." The Bonanza crashed not far away.
Total flight experience was not an issue. The captain of the DC-3 had more than 4,400 hours of flight time, with nearly 3,800 in the DC-3. The pilot of the A36 had 28,600 hours of flight time, with more than 2,300 in the Bonanza. There was no indication of the formation flight experience of either pilot.
As mentioned earlier, formation mishaps occasionally happen with the professionals as well. Four Stearman biplanes were flying in formation during an airshow. According to the flight leader, they had just completed an arrowhead formation. The number-two and number-three airplanes moved into diamond formation. The flight team completed the five-eighths-loop portion of a one-half Cuban eight, set the 45-degree inverted downline, completed a one-half roll to the upright position, and was beginning the entry into a clover loop when the accident occurred. Witnesses and video from TV stations indicated that the flight leader, number-three, and number-four airplanes started pulling up out of a dive to initiate the diamond clover loop, while the number-two airplane continued to descend and collided with the number-four airplane. The NTSB determined that the probable cause was failure of the number-two pilot to maintain visual contact and/or proper position/clearance from other aircraft.
Precision formations are not the only sources of collisions. Something as simple as a flyby in close proximity to other aircraft can be a problem, particularly when one of the players doesn't follow the rules of engagement. The plan can be very simple—stick to your altitude and there will be no trouble. Three airplanes were making flybys at an airshow. The pilots were briefed to prepare for multiple passes. The faster airplane, a Cessna 337 (push-pull twin), was assigned a minimum altitude of 500 feet agl, while the two slower airplanes, a Piper J-3 followed by a Cessna 305 (Birddog or L-19), were restricted from climbing above 200 feet agl. After the Cessna 337 made one flyby, the Piper and Cessna 305 flew by. Passing show center, the Piper remained below 200 feet agl. However, the Cessna 305 initiated a climb as the Cessna 337 returned for his second pass. Witnesses reported that the air boss advised the pilot of the Cessna 337 that the Cessna 305 was climbing.
The downward visibility over the nose of the Cessna 337 restricted the pilot from seeing the Cessna 305 until it appeared in front of him. Cessna documents state that the average over-the-nose visibility is only about 5 degrees. At the time of the collision, the Cessna 337 was maneuvering to the right and descending. The Cessna 305 was in a wings-level climb straight ahead. The NTSB suggested that the probable cause was the failure of the Cessna 305 pilot to follow the instructions issued, and maintain a low altitude. A factor was the delay in evasive action by the Cessna 337 pilot after he was first advised that the Cessna 305 was climbing. The Cessna 337 pilot had flown his routine in roughly 30 shows. The Cessna 305 pilot had performed in shows before but the number was unknown. The Piper pilot said that the 305 pilot "appeared nervous" at the preshow briefing.
A Cessna 182 pilot called the tower and advised departing as a flight of two behind a Piper Arrow. The passenger in the Piper reported that shortly before the two aircraft collided, he observed the Cessna 182 about 45 degrees aft and to the right well below the Arrow, but then lost sight of the Cessna. The Cessna's line of sight to the sun, just before the collision, was computed to be at the 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 quite 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 aircraft 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, as required by the FARs.
The NTSB noted inadequate prior arrangements for formation flight by the Cessna 182 pilot and his subsequent failure to see and avoid the Piper. Other factors were the impairment by the sun of the Cessna pilot's visibility of the Piper; restricted visibility from both aircraft because of low-wing/high-wing formation configuration; and the Piper pilot's attention diverted to other traffic.
There are very few rules regarding formation flight. FAR 91.111 states that "no person may operate so close to another aircraft as to create a collision hazard." There's a profound thought. There must be prior arrangement so that each pilot in the formation knows about the proposed operation and agrees to it. Finally, formation flight with paying passengers on board is prohibited.
There is reward and satisfaction in formation flight. However, to approach even a basic level of safety, there must be a commensurate passion and enthusiasm. To become skilled, pilots must invest in the training and practice. A casual approach is not appropriate to this activity. Will you trust your life and that of everyone on board your aircraft to the skill of the other pilot? With proper training and practice it can be done, but don't be deluded into thinking it's a walk in the park. The record tends to indicate otherwise.
See also the index of "Safety Pilot" articles, organized by subject.
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