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Avionics History: 1976: What a Year for Avionics

By David Underwood | July 1, 2001
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THE CONTINENTAL DIVIDE, as we learned in school, is America's great watershed. Rain falling to its west ends up, eventually, in the Pacific, while that falling to the East feeds the Atlantic and the Gulf of Mexico.

For the avionics industry, 1976 was a watershed, in no small part, we would like to think, because it was the launch year forAvionics Magazine. But, of course, much more took place 25 years ago.

Remember NAVSTAR?

For example, it was a quarter century ago when the U.S. Department of Defense (DoD) presented industry briefings in the United States, Canada and other Western nations of its future satellite navigation project, which we know today as the Global Positioning System (GPS). At that time, DoD referred to the system as NAVSTAR, for NAVigation Satellite Timing And Ranging. The GPS acronym gradually replaced NAVSTAR by the mid-1980s.

For briefing attendees, NAVSTAR was breathtaking. The notion that one day users with small, low-cost devices could locate themselves within 500 meters (1,640 feet) of their true geographic position anywhere on Earth, from the surface right up to jet altitudes, at all times and in any weather, was truly revolutionary. And from that time on, just about everything was going to change.

And, yes, I did say 500 meters, because that was originally the accuracy in which civil users were to be allowed. This was according to the DoD's edict at the time that while the military would enjoy top performance, civilians could have only the accuracy then understood to be available from GLONASS, a NAVSTAR-like system being developed in parallel by the then Soviet Union (dissolved in 1991).

It was several more years before DoD, succumbing to pressure during Congressional budget hearings, reduced their civil accuracy limit to 100 meters (330 feet). But 25 years ago, 500 meters everywhere on Earth was regarded as an astonishing achievement.

It certainly astounded attendees at the packed briefing, which I attended in the auditorium of Canada's National Research Council in 1976. Col. Bradford Parkinson, head of the U.S. Air Force's NAVSTAR presented the briefing, describing capabilities that have had tremendous implications for navigation, exploration, aerial surveying and even search and rescue, over Canada's vast northern reaches.

A Journalistic First

Although 1976 would turn out to be the navigational watershed for the world, that fact wasn't widely appreciated at the time. Nor for some years following, due to a limited number of satellites in orbit and the unavailability of affordable avionics.

In 1990, for example, the U.S. Federal Aviation Administration's (FAA's) Technical Center invited the aviation press to attend system flight demonstrations at Atlantic City. Only one publication responded, and it didn't cover the air transport industry, but rather wasAvionics Magazine'snow sister publication,Rotor & Wing,which covers the rotary-wing industry. My assignment fromRotor & Wingcaused me inadvertently to become the first aviation journalist in the world to fly with GPS.

Flying in a Marine Corps Sikorsky S-62, and using a $120,000 Magnavox "Z" receiver borrowed from the U.S. Air Force, we evaluated the new system's non-precision approach capabilities over Chesapeake Bay. It was during a 95-minute "window" in the late afternoon, when all four test satellites could be seen simultaneously above the horizon. It was an impressive demonstration, even though, on our final touchdown at the Technical Center ramp at the end of the sortie, the "Z" receiver told us we were precisely 45 feet (13.7 meters) below ground level.

Nevertheless, from then onwards, these and other civil flight evaluations showed clearly that the clock started ticking on all our terrestrial navaids, and also on the way we viewed traveling from one point to another. Today, of course, small, low-cost GPS units can be found in almost every walk of life, with aviation becoming one of its smaller user groups.

It's interesting, in fact, to look back at 1976 and recall how we flew from A to B. For the airlines, the basic, worldwide navaid was Omega, a very low frequency system with typical accuracy of about one mile by day, reduced to two miles at night as it fell victim to ionospheric disturbances. Some wealthier airlines had invested in inertial navigation systems (INS), which is highly accurate on departure but with cumulative errors of up to 10 miles after an oceanic crossing. Also the INS' high acquisition costs were only surpassed by its even higher maintenance expense. Other aircraft that flew long distances still used Doppler radar systems, which were often beset with unpredictable drift rates and other errors.

But for small operators and general aviation, navigation meant using just two systems: the VHF omni-range (VOR) and the automatic direction finder (ADF). Distance measuring equipment (DME) was still out of reach for most low-budget fliers, and while some private pilots had reported impressive results from shoehorning bulky marine Loran-C units into their cockpits, the landslide in airborne Loran was still many years away.

Only a few years earlier, in fact, the FAA had decommissioned its last radio range in Alaska. The low-frequency radio range, with its four "on-course" legs and its interspersed Morse A and N signals, had been both reviled as a curse and praised as a Godsend by pilots since the 1930s, when it was established as the backbone of the nation's fledgling airways structure. (To understand what "flying the range" was about, younger pilots should read any of Ernest K. Gann's novels; they're aviation classics.)

Collision Avoidance

But futurists at RTCA and elsewhere were looking in 1976 towards other new technologies besides GPS to solve the capacity and safety problems, which they foresaw for civil aviation by the turn of the century. One major issue was collision avoidance. Various promising techniques in this area had been evaluated since the mid-1960s, but each was disqualified for different reasons. This process continued in 1976 and was only halted two years later when then FAA Administrator Lynn Helms decided that enough testing had been done and named the traffic alert and collision avoidance system (TCAS) as the future national standard. Today, TCAS is standard equipment in the aircraft of all large air carriers, with several developments underway to provide similar capabilities for general aviation.

A somewhat similar history surrounded the development of the microwave landing system (MLS), which was conceived in the early 1970s to meet the need for a future replacement for the instrument landing system (ILS). Various techniques, developed in the United States, United Kingdom, Germany and Australia, were evaluated, with the U.S. system being finally adopted in 1977 by the International Civil Aviation Organization (ICAO) as the future world standard.

But unlike TCAS, MLS never caught on. In 1985, in the light of imminent GPS landing system developments, ICAO switched from mandatory to optional world conversion from ILS to MLS. Today, MLS has been adopted by several European nations as their future all-weather landing system. But the United States, which established the MLS standard, and the rest of the world opted to await the arrival of GPS as their ILS replacement.

And what happened to the U.S. Air Force's Col. Parkinson? He retired from the military and subsequently became chief executive officer of Trimble Navigation. Later, he became a professor at California's Stanford University and was chosen last year to chair an FAA-appointed, high-level Independent Review Board, charged with examining the state of the agency's Wide Area Augmentation System (WAAS) and GPS programs. It, therefore, fell to Parkinson earlier this year to pass on the Review Board's disappointing verdict that the replacement of ILS by GPS would now not take place until the 2011-to-2015 timeframe, for technical and financial reasons.

Memorable Brands, Individuals

For those who go back to 1976 and before, there is the memory of the companies and the product names that are no more. Narco and its Marks 12 and 24 nav/coms, for example. Or Sun Air's line of radios, with its optional color control heads. Or King Radio's Silver and Gold Crown products. Or Foster Air Data's ingenious VNav guidance units. Or monochrome weather radar (who remembers those?). Or the innovative Bonzer radio altimeter.

This also was the time of airlines like Eastern, Braniff (the original one, that is), PeoplExpress, and others long since vanished. And it was the time of the upstart Federal Express, which launched an impossible dream with a small fleet of purple and white Dassault Falcons--but 25 years later, plans to operate a fleet of gargantuan Airbus 380s.

Yet perhaps one of the most significant changes in the avionics industry since the 1970s has been the increasing lack of memorable individuals. Today, the industry appears to be run by polite, well-dressed and always politically correct, gentlemen with MBAs. That's very nice, of course, but one does occasionally long for the days when there were any number of rugged individualists making the dust fly.

VNav pioneer George Foster was such a person. With a doctorate in nuclear physics and a brilliant technical mind, which he applied successfully to the solution and practical application of VNav algorithms back in the 1970s, George was still the guy you'd want by your side in a bar room brawl. After our first meeting, and with some trepidation, I likened him in a magazine story to the movie star George C. Scott, of "Patton" fame. He loved it, I was told later.

And then there was George Church, vice president-engineering at Bendix Avionics, a keen sailplane enthusiast with a wicked sense of humor. When taking a commercial flight to a sailplane meet, long before rigid security screening, George would delight in carrying his parachute pack up to the check-in counter and insist that he take it with him as hand baggage.

Many also may remember the ever-cheerful Gil Quinby of Narco and the always-smiling Craig Christie, the good ol' boy from King Radio. And everyone had a story back then about Bill Lear, a true genius who was designing and building avionics equipment long before he started building airplanes.

My favorite one concerns the young Bendix Radio salesman who tried to sell his firm's T-12 ADF for Lear's new jets, but couldn't answer Lear's technically probing questions. Finally, Lear threw him out of the office, telling him not to return until he knew more about his unit than Lear did. It was only later that the young man learned that Lear had designed and built the original T-12, and had subsequently sold the rights to Bendix.

In the midst of this atmosphere of colorful individuals and new technical developments, an accomplished technical writer in Leesville, Va., Len Buckwalter, and his wife, Mary, decided in 1976 to launch a publication covering the avionics industry. Originally a newsletter, it became a four-color magazine in 1980, introduced at that year's National Business Aviation Association (NBAA) exhibition. Len wrote the copy and Mary sold the advertising space.Avionics Magazinegrew and eventually was sold to Phillips Publishing Inc., which became PBI Media LLC, the magazine's owner today.

So, yes, 1976 was a memorable year. But as Mae West said, several years earlier, "You ain't seen nothin' yet."


In the general aviation marketplace, the following happened in 1976:

  • Don Taylor makes the first round-the-world flight in a home-built airplane, a Thorp T-18.

  • Piper Aircraft rolls out its 100,000th aircraft, a Cheyenne twin turboprop.

  • Champion golfer Arnold Palmer makes a record-breaking flight around the world in a light aircraft, the Gates Learjet 200. At slightly less than 29 hours flying time, he beats the old record, set by radio personality Arthur Godfrey.

  • The first U.S. designed twin-engine light commercial helicopter, the Bell 222, flies for the first time.

  • The Learjet 35A, 36A and 24F receive FAA certification.

1976--In the News

  • Tragic earthquake strikes China, killing 655,000 people;

  • Riots break out in Soweto, protesting South Africa's apartheid policies;

  • Winter Olympics are in Innsbruck and Summer Olympics are in Montreal;

  • The United States celebrates its bicentennial anniversary;

  • Punk rock groups like the Sex Pistols reach peak popularity; and

  • Chinese Communist leader Mao Zedong dies.

1976--In the Military Market

In military aviation, here are some of the things that happened in 1976:

  • The McDonnell Douglas F-15 Eagle and Fairchild A-10 Thunderbolt II enter service with the U.S. Air Force.

  • The first full-scale development General Dynamics F-16 makes its maiden flight, as does the Boeing E-3A Sentry AWACS, fitted with full mission avionics.

  • A U.S. Navy Grumman A-6 Intruder launches the first fully guided Tomahawk cruise missile.

  • The U.S. Navy phases out the last Douglas C-117D, ending the DC-3 derivative's 35 years of service. The Navy also retires its last seaplane, the Grumman HU-16 Albatross.

  • The governments of the UK, German and Italy approve full production of the Tornado.

  • U.S. Defense Secretary Donald Rumsfeld announces contracts for limited production of the B-1 bomber.

  • The U.S. Army selects the Hughes AH-64A as its advanced attack helicopter and the S-70 Black Hawk as its tactical transport helicopter.

  • The SR-71 Blackbird reconnaissance aircraft breaks both a speed record--2,193 mph (3,529 kmph) over a 15/25-km course--and an altitude-in-horizontal-flight record at 85,069 feet.

1976--In Air Transport

These are some of the benchmarks in 1976 in the air transport market:

  • The Concorde makes a sales tour to the Far East, but the supersonic airliner's future remains murky, as its landings in the U.S. are allowed only for a 16-month trial period.

  • The Free World's scheduled airlines carries a total of 576 million passengers, with a 60% load factor.

  • An Air France Airbus 300B2 on its way to Tel Aviv, Israel, is hijacked after departing Athens, Greece.The aircraft is taken to Entebbe, Uganda, where Israeli special forces subsequently overwhelm the terrorists and rescue the passengers and crew.

  • British Airways makes an initial order for six Lockheed L-1011 TriStars, to replace its VC-10 and Boeing 707 airliners.

  • Brazil's first pressurized, twin-turboprop, the Embraer EMB-121 Xingu, makes its first flight, as does the Ilyushin Il-86, the Soviet Union's first large-capacity, widebody commercial transport aircraft.

1976--In Avionics

In the world of avionics, here are some of the events occurring in 1976:

  • An International Civil Aviation Organization (ICAO) working group gathers to establish standards for the next-generation, international approach aid, the microwave landing system (MLS), replacing the instrument landing system (ILS).

  • The National Weather Service begins trials of low-altitude windshear forecasting.

  • The U.S. Federal Aviation Administration (FAA) completes installing a conflict alert system at 20 air traffic control centers--designed to project the next two minutes of a flight path followed by aircraft at altitudes above 18,000 feet.

  • The FAA proposes the establishment of an avionics technician rating.

  • VLF for en route IFR area navigation has been approved by the FAA, and Global Navigation's GNS-500A VLF/Omega area navigation (RNAV) becomes the first such system to be certified as a primary navigational aid.

  • The FAA approves 3-dimensional area navigation (3-D RNAV) for en-route and approach instrument flight rules (IFR). This marks the first certification of the vertical navigation (VNAV) portion of RNAV.

1976--In the U.S. Aviation Marketplace

  • 16,429 aircraft are built for the civil market, including 54 transports, 527 helicopters, and 13,441 general aviation aircraft.

  • The U.S. military took delivery of 454 aircraft.

  • 680 military aircraft were exported.

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