Editor's Note: The Race for ADS-B

There is a race going on —a race against time. Pressure is mounting against the Cargo Airline Association (CAA), which is working feverishly to make automatic dependent surveillance-broadcast (ADS-B) a viable contributor to safe, efficient air operations. ADS-B provides pilots with an awareness of proximate traffic. Part of its promise lies in its economics; it requires little expense in terms of equipage on aircraft.

From our coverage of an operational evaluation (OpEval) conducted this summer by the CAA in the Ohio River Valley, we discovered that ADS-B truly can be beneficial. But as diligently as the CAA works to develop ADS-B, no one can say for sure when the technology will be fully approved and ready for implementation. Meanwhile, pressure mounts to have cargo aircraft equipped to prevent midair accidents.

That pressure came, in part, on Sept. 9 when the National Transportation Safety Board (NTSB) sent a safety recommendation to the U.S. Federal Aviation Administration (FAA), urging the agency to require cargo aircraft to be equipped with traffic alert and collision avoidance systems (TCAS). This would join cargo carriers with their passenger bearing brethren, which must have TCAS. It would also join cargo aircraft flying in the United States with their European counterparts. Regulations in Europe will require that all aircraft weighing 33,000 pounds (15,000 kg)—whether they bear passengers or cargo—be equipped with the equivalent of TCAS II by Jan. 1, 2000.

Europe’s edict applies still more pressure on the U.S. cargo carriers. In response, United Parcel Service announced it would install TCAS II on its aircraft used for international service. Federal Express volunteered to equip its entire fleet with the system.

But TCAS isn’t cheap. Some say with only slight exaggeration that TCAS' approximate $150,000 price tag makes the system worth more than some of the aircraft on which it is to be mounted. Hence, the fervent desire among cargo airlines for an alternative like ADS-B.

The balance of safety and economics represents a story as old as commercial aviation itself. Commercial air operations must be safe, of course, but they also must be economical enough to exist at all.

The NTSB’s safety recommendation noted efforts in the U.S. Congress to make the TCAS requirement on cargo planes part of this year’s FAA reauthorization legislation. FAA has said it supports collision avoidance equipment on cargo aircraft, but has issued no rulemaking. The agency also supports efforts to advance ADS-B.

The NTSB makes a strong argument for the TCAS requirement. It leads its safety recommendation with accounts of two reported, near midair collisions. Among the four aircraft involved, only one took diversionary action—the one equipped with TCAS. The NTSB says it recognizes the progress made in ADS-B, but states that collision avoidance "is not its primary function, and no firm schedule or implementation plan [for ADS-B] has been established."

Requiring TCAS on cargo planes will undoubtedly enhance safety. TCAS is proven technology. But there still is a downside to its requirement on cargo aircraft: It could put the brakes on the CAA’s effort to advance ADS-B. The association would have less incentive to continuing the technology’s development. In short, the race could be ended before the finish line is reached.