Collision Avoidance Systems Proposed for Cargo Aircraft

Air Safety Week, Nov 19, 2001

Initiative responds to legislation enacted to force action

A significant step has been taken toward the oft-proclaimed goal of a "single level of safety" that should greatly help reduce the threat of mid-air collisions. Traffic Alert and Collision Avoidance System (TCAS) technology must be installed in all-cargo aircraft and the particular technology must provide commonality throughout the fleet, according to an October 31 Notice of Proposed Rulemaking (Docket No. FAA-2001-10910). In this document, the Federal Aviation Administration (FAA) is calling for not only fleetwide equipage, but also fleetwide standardization of collision avoidance technology.

Advocates of alternative collision-avoidance systems to TCAS, such as ADS-B (automatic dependent surveillance, broadcast), must demonstrate that their approach provides an equivalent level of protection. In this respect, the FAA has placed the burden of proof on advocates of other technologies. ADS-B, designed to fulfill the surveillance function based on signals from the global positioning system (GPS), thereby providing the potential to track aircraft without need of ground radars, was not intended originally to provide collision avoidance. To demonstrate what might be called a TCAS-like capability, the FAA has laid down a very specific set of markers.

Cargo pilots are, to say the least, heartened. "We're belatedly happy," said Mike Cronin, speaking for the Coalition of Airline Pilots Associations (CAPA), a group of labor unions representing most of the pilots flying for the major cargo carriers. Cronin, a recently-retired American Airlines [AMR] captain, said of the FAA initiative, "We think they got it right."

For the past few years, cargo pilots have complained bitterly that the FAA's failure to mandate TCAS for their airplanes was an affront to the single level of safety ethic. They claimed they were flying in the same airspace as passenger aircraft, and that a mid-air collision with a passenger airliner could wreak considerable destruction in the air and on the ground. The FAA's declaration in an earlier document about TCAS that cargo pilots' lives were essentially worthless for cost-benefit purposes was particularly galling. The perception that they were expendable prompted many sharp remarks from cargo pilots about the FAA's seemingly callous approach to their safety.

Common capability needed

The FAA is now singing a different tune. "Cargo operations are increasingly occurring around the clock and these operations occur in airspace shared with passenger airplanes," the NPRM intoned. The NPRM explained that when the original TCAS rule was published in 1989, the intent was to protect passengers from midair collisions. Cargo planes were excluded because they operated relatively few airplanes (about 375), mostly at night, while the passenger planes were flying mostly in the day. At that point in history, the NPRM recalled, "The cost-benefit analysis and risk level...did not support requiring cargo operators to equip their airplanes with TCAS." Today, some 1,150 cargo jets are flying, at all hours of the day, and their number is projected to grow by 5 percent or more for the next 10 years. Changed circumstances warrant expanding the TCAS requirement to include cargo planes, the NPRM declared.

TCAS has benefited safety. In the first six years since the installation of TCAS began for passenger airliners, the number of pilot-reported near mid-air collisions dropped a whopping 60 percent. On the other hand, there have been some hairy close-calls involving cargo aircraft: a cargo-passenger incident in February 1999, in which the TCAS-equipped passenger jet took evasive action, and a really frightening incident in March 1999 involving two cargo jets. Officially, the planes came within a half-mile of each other (with zero feet vertical separation) in the nighttime incident over Salinas, Kansas. However, the copilot of one of these jets recalled hearing the sound of a very close call (He was in the lavatory at the time, thinking it was a hell of a place for a pilot to die in a midair collision, he recalled in a conversation with this writer last year).

The FAA is now decreeing that the 30-passenger seating threshold for TCAS needs to be expanded to more simply include those cargo and passenger jets with a takeoff weight of 33,000 pounds or more. The minimum number of passengers requirement has been eliminated; aircraft weight is now the sole threshold (although on-demand charter and corporate aircraft are not required to have TCAS). The weight standard responds to a recommendation from the U.S. National Transportation Safety Board (NTSB).

The clock is ticking

In any event, the mandate is for TCAS to be installed in all-cargo airplanes by October 31, 2003. Whether this deadline provides enough time for operators to install TCAS in more than 1,100 all-cargo jets remains to be seen. That deadline is just some 24 months hence, and, after comments to the NPRM have been processed and the final rule issued, operators may not have enough time to comply.