A safe flight is a puzzle. Put all the pieces together correctly and you can get a pretty picture indeed. If one piece is missing, you can still see the picture, usually. But sometimes, if the wrong piece is missing, the puzzle is ruined. Unfortunately, when a piece is missing from the safety of flight, the price is higher than merely sighing and putting the puzzle box back in the closet.
Pilots love to talk about accident scenarios in terms of chains. Break one link and the chain fails, sending all of the airplanes occupants home to have dinner with their loved ones. Its a nice story. It has closure and finality. Its also a myth.
An accident can also be caused by something as small as a bug splatter on the windshield, a missed radio call or the assumption that someone else is looking out for you.
On a Saturday evening in July, the pilot of a Cessna 172 boarded three paying passengers in Lansing, Ill., for a sightseeing flight of the Chicago skyline. The pilot was a 22-year-old CFII with nearly 800 hours who was flying 50 to 60 hours a month.
The Cessna flew north along the shoreline, following a relatively standard company practice for sightseeing flights. The pilot called the Meigs Tower and reported in at 1,900 feet, 10 miles south of the airport, inbound for transition up the lake shore. The controller approved the transition northbound and issued the altimeter reading.
A few minutes later, as the Cessna approached Meigs airspace, the Tower controller issued a traffic advisory. A Beech Bonanza that had tried to land at Meigs earlier had reported landing gear problems and was holding at 1,700 feet over a local landmark known as the south crib, a water intake facility on the shore of Lake Michigan about four miles south of the airport. The pilot acknowledged the advisory.
As the Cessna approached Meigs, the pilot requested a low approach to runway 36, the active runway. At the time of the request, the Cessna was about 1 mile southeast of the field. Almost immediately after making the request, the Cessna pilot reported turning final for the runway. At that point, the controller cleared the pilot for the low approach. The controller asked the pilots intentions after the approach, and the pilot said the flight would continue northbound past the Navy pier, then make a 180-degree turn and a return southbound. The controller asked the pilot to report before making the 180-degree turn.
At 6:01:47 p.m., the pilot reported beginning the turn back to the south. The controller acknowledged and instructed the pilot to report abeam. The pilot acknowledged. Then the controller issued a traffic advisory for another airplane inbound to Meigs from the north. Again the pilot acknowledged. That was the last transmission the pilot made.
Only seconds after the Cessna pilot acknowledged the traffic advisory, a Bonanza A-36 that had departed Michigan City, Ind., called the controller, reporting nine miles to the south at 2,600 feet, inbound for Meigs. The Bonanza was being piloted by a 1,400-hour private pilot, with 2,400-hour commercial pilot in the right seat and one other occupant. The controller advised the Bonanza pilot about the other Bonanza holding over the south crib, but the pilot replied he was unfamiliar with the landmark. The controller replied the airplane was holding about four miles south/southeast of the airport at 1,700 feet.
As the inbound Bonanza passed the Bonanza that was holding, the controller cleared the inbound flight to land. The pilot, noting he was about four miles south, reported he did not have the crib traffic – the holding Bonanza – in sight. The controller asked the pilot to report his position, but got no response.
What the controller could not see through the haze was that the descending Bonanza and the southbound Cessna collided in mid-air. There were many witnesses to the accident, several of whom were pilots. None reported either airplane taking any evasive action in the seconds before the collision. The Cessna exploded and plunged into the lake. The Bonanza continued on for several seconds before tumbling down. All seven people aboard the two airplanes were killed.
When the wreckage was recovered, investigators concluded the left wing of the Cessna hit the left wing and fuselage of the Bonanza, essentially slicing off the top half of the Bonanzas fuselage. The Cessnas wing broke off and the fuel ignited.
The FAA subscribes to a standard that it takes about 12.3 seconds under ideal conditions to evaluate a target, determine its a collision threat, and begin evasive action. By combining the airplanes flight paths, wreckage evidence, visibility and witness statements, investigators were able to determine that each airplane would have been visible to the other for about 25 seconds, each in the center of the windshield and a bit low.
There were other smoking guns to be found, as well. The NTSB noted in its investigation that the Cessna pilot did not report abeam the airport as she transitioned southbound, as instructed. The controller on duty at the time said she uses those position reports to help keep track of where the traffic is.
The tower at Meigs operates as an FAA contract tower, staffed by a single full-performance controller on weekends. At the time of the accident, a trainee was also at the facility. As fate would have it, the Meigs tower had been designated to become a contract tower and a contract was awarded in 1994, to take effect in 1996. The brief closing of Meigs by the city of Chicago in 1996 delayed the opening of the contract facility until the airport reopened in 1997.
The controversy over the airport had already taken another toll, however. The FAA had put Meigs on the list of airports to receive Digital Bright Radar Indicator Tower Equipment, or D-BRITE in 1990. The equipment was delivered to the tower but never installed because of the ongoing attempts by the city to close the airport. In 1992, the equipment was delivered to Gary, Ind., and installed there.
To be eligible for D-BRITE, a tower has to be part of a hub, handle more than 30,000 airplanes per year and have sufficient low-altitude radar coverage. Meigs qualified on all counts, handling nearly 25,000 flights in the four months leading up to the mid-air. The FAA has no plans to install additional D-BRITE equipment, which operates off of a direct feed from the hubs radar antenna. Instead, it uses the newer Terminal Automated Radar Display and Information System, or TARDIS, which operates off the transponder returns of airplanes rather than the direct radar feed.
Shortly after the accident, TARDIS was installed at Meigs, but the NTSB reports that 67 other contract towers and 20 FAA-operated towers meet the criteria for TARDIS installation but do not have the equipment installed.
After the accident, critics were quick to blame the contract tower for not having the proper equipment and not having sufficient staff at the facility. In fact, city officials shut Meigs down briefly after the collision until the FAA gave assurances the situation would be investigated.
That reaction misses the point, however, that a tower such as Meigs is not responsible for traffic separation. Meigs is a Level 1, VFR only tower where radio contact is required. When the tower is operating, it is Class D airspace.
It may be tempting to ascribe the accident chain pattern to the collision, and in some ways there was a chain of errors involved. But the fundamental error rests with the pilots aboard the airplanes.
The position report the Cessna pilot failed to make may have made a difference. The presence of D-BRITE or even earlier installation of TARDIS may have made a difference. But the fact remains that two VFR pilots failed to see and avoid other traffic.
Nor is this situation unique. A review of mid-air collisions shows that the overwhelming majority occur between two VFR airplanes in daylight conditions near airport traffic areas. To some, that calls for a hardware solution. To others, more training may be necessary.
As Aviation Safety reports elsewhere in this issue, on-board collision avoidance equipment for GA airplanes is expensive and its worth is questionable. Although training is often held out as the least effective way of preventing errors, there are some fundamental training issues that may come into play in mid-air collisions.
Efficient scanning technique has been developed by both civil and military research, and several FAA publications refer to it. Many student texts, however, do not. Most instructors place only passing emphasis on it during training, and few address it at all during recurrent training or biennial flight reviews.
The fact remains that an airplane on a nearly head-on collision course will appear first as a stationary speck on the windshield, like a bug splatter that you neglected to clean off after the last flight. Because it doesnt move relative positions, it grows slowly until suddenly it seems to explode in size as the collision becomes imminent.
See and avoid is a necessity to which any pilot will pay lip service. But the active scan outside is easy to neglect while on a sightseeing flight or preparing the aircraft for landing. Ironically, those are the times when its most necessary, as the Meigs collision bears all-too-tragic witness.
-by Ken Ibold