Air Transport World

Where, oh where has MLS been? (microwave landing system)(includes articles about FAA's Joseph M. Del Balzo and MLS doubters)

At the end of the decade in which new electronics technologies were to alter the aviation landscape, they are still in the future. By William Reynish.

Moving into a new decade allows both the optimism of foresight and the benefit of hindsight. Ten years ago, aviation looked ahead to a future of TCAS, Mode S, satellite navigation and the microwave landing system (MLS). All promised to provide increased efficiency, safety and reduced operator costs through the use of new electronic technology, some as early as the late 1980s. Nary a murmur of dissent was heard. Ten years later, all four are still out there, miragelike, in the future. The promises are still valid but the murmuring has gotten a lot louder.

MLS is typical. in the late 1970s, when ICAO unanimously adopted it as the successor to the current instrument landing system (ILS) after much U.S. pressure, the agreed-upon 1995 transition date seemed comfortably far away, allowing ample time to accommodate new airport and aircraft equipment. FAA's 1984 contract with Hazeltine Corp. of Greenlawn, N.Y., would see 178 lower-accuracy Category I systems installed by 1989 in local hub-and-spoke layouts throughout the country, which would form the basis of a nationwide, 1,250-system network-incorporating higher-precision Category II and III equipment at appropriate locations-by the mids. '90 At that time, MLS installations would be almost double the 700 or so ILS units in service and would allow a smooth transition to the new system.

Contract canceled

Unfortunately, it did not work out that way. By 1988, only two of the 178 systems had been delivered and Hazeltine and the FAA were in a contractual standoff. in 1989, FAA canceled Hazeltine's contract for default. Attempts to rescue the contract by novation, i.e., transferring it to other companies have been unsuccessful, leaving the FAA with just a handful of test systems at various locations in 1990, a much-delayed national-implementation program and an army of skeptics.

The most vocal of these is the Aircraft Owners and Pilots Association (AOPA), which out of concern about the cost to its members of MLS equipage vs. the system's benefits, has demanded that FAA cancel its MLS program and switch to the Defense Department's satellite-based Global Positioning System (GPS) for precision approach guidance. Paradoxically, DOD has ordered MLS because it says its GPS can't provide such guidance. …

Log in to your account to read this article – and millions more.