Air Line Pilot, June/July 1999, page 16

By Capt. Tom Duke (Ret.)

As the debate rages over how to overcome impending gridlock on U.S. airways and airports, I recall the chaotic days in Saigon in the early 1970s. I had been assigned as the safety officer for the C-130 tactical airlifters at Saigon’s Tan Son Nhut, then the world’s busiest airfield.

At the time, we had the North Vietnamese on the run and were attempting to turn the war over to the South Vietnamese. I shared my office with the intelligence briefer, who consistently offered a different view of the situation. Our door was just off the crew briefing room, which was a round-the-clock operation. My office was directly below the commander’s. I briefed him at 1900 daily during a session we came to call "vespers." The final decision of the day was "where we going for dinner?" The Colonel had the wheels.

We had as many as 38 aircraft per day flying an average of six legs apiece, many into austere 3,000-foot dirt strips that Special Forces maintained. Others were into major airfields with extremely high-density traffic. All the flying was conducted under loose visual rules—not the "free flight" we are trying to achieve today, but perhaps akin to it. They called it "Special VFR." To my amazement, it worked out well.

My prior experience had been 100 percent instrument flight rules, even on training flights, in the busy Washington, D.C., area. I had flown in and out of Saigon dozens of times in a VC-135B on IFR flight plans with some strange anomalies.

I once was vectored up the Saigon River at midnight with the city and airport almost in total darkness. We descended to 700 feet, with city and airfield lights out but with bright phosphorous lights all around. We were asked to spot the airfield at 10 o’clock and land. The runway and approach lights went on suddenly, and were turned off as I rolled down the runway. At dispatch, they told me the North Vietnamese, the enemy, considered my aircraft a mortar magnet. We were fueled and loaded in total darkness. Thirty minutes later, we were given a departure vector on a safe course to 6,500 feet and proceeded on our own navigation with customary IFR clearances.

Another time I filed IFR from Saigon to Chu Lai, a Marine base on the east coast. After takeoff, I was vectored by approach control and turned over to an enroute frequency. Almost immediately, I was advised, "Radar contact lost, say your estimate for xxx." We had reverted to 1950s stateside enroute procedures. Before losing Saigon ATC radio contact, I was cleared down to 20,000 feet at pilot’s discretion and turned over to Chu Lai Tower for further descent.

The Marines advised me, "Unable IFR due to recovery and military operations. Will you accept ‘feet wet’ arrival?" Our stateside crew looked at each other and, in an early version of crew resource management (quick thinking), agreed, provided we could follow a letdown plate. We found the term "feet wet" in the J-aid—it meant letting down offshore away from gun fire and air-to-ground operations.

We descended on a 15-mile arc through the soup to below clouds at 1,000 feet and headed on the letdown plate vector for the airfield visually for a circling, close-in landing approach. At the last minute on final, they advised us it might be a good idea that, because we did not have a tail hook on our VC-135, we should "land beyond the arresting gear." So much for a stable approach. So much for IFR in Vietnam.

Naturally, as the newly assigned safety officer, I was curious about how 38 aircraft per day were surviving in that ATC environment. I arranged a jumpseat ride with one of the crews and watched them at work. The dispatch clearance was good for all day and usually involved at least six landings anywhere in South Vietnam, sometimes in Cambodia.

On a C-130, the flight engineer sits between the pilots and the navigator sits sidesaddle behind the copilot. Everyone has a panoramic view. The flight deck is very noisy, so everyone wears earphones and talks on interphone.

After engine start, the airplane had to back out of the revetment under its own power with the loadmaster observing taxi operations behind us and giving directions while lying on his belly on the open rear cargo door. Once the airplane was headed toward the runway, ground control was standard with occasional advisories that a helicopter was flying overhead about to land.

All aircraft made rolling takeoffs in turn under tower clearance and timing, usually once the aircraft ahead had lifted off or the landing aircraft had cleared the runway. At times, two takeoffs per minute per runway were possible, depending on the type of aircraft ahead of you. I noted that the tower cleared all runway crossings when aircraft were in a position to hurry.

Once airborne, the nonflying pilot contacted tactical radar to advise his position, destination, and proposed altitude and to ask for traffic and flight following. Radar assigned a transponder setting, gave traffic, if any, and asked to be informed when changing course or altitude or starting descent. The dispatcher was also contacted with blocks/off times and expected arrival times.

The pilots remained clear of clouds whenever possible. Special VFR allowed cloud and visibility minimums of about half stateside VFR rules. When penetrating cloud was absolutely necessary, the crew advised radar—and any other aircraft in radio range—of their location and intentions. Flying in cloud was supposed to be brief and temporary. The frequency was busy, transmissions concise and accurate. In this C-130 cockpit, four heads plus mine were on a swivel looking out for other aircraft and ways around weather and clouds.

Occasionally, flight crews spotted other aircraft and talked over possible course and altitude conflicts on the common frequency for that sector. When two aircraft were heading for the same destination, the crews worked out who was first to land with the ground handlers who knew which cargo was the most needed. Most airfields could handle more than one aircraft at a time.

On arrival, the crew informed the ground party, whether an Army unit or airport tower, of their location and arrival time and usually landed straight in to avoid low-altitude artillery or rifle fire. The navigator had a third radio equipped with Army FM frequencies to contact friendly artillery units when flying below 6,500 feet. He advised the Army of his intentions and requested they hold their fire. This was no guarantee that ground fire would cease. Sometimes the navigator would tell the pilot where to go based on artillery information or magical computations.

Some austere airfields had a low-powered beacon or radar reflectors so the navigator could devise ad hoc approaches on the radar scope to line up on final or decide when to begin a safe descent to an altitude from which a landing could be made. The runways were marked with two sets of painted 55-gallon drums that indicated the touchdown area and were somewhat useful as a glideslope visual aid.

Landings were precise, final approaches on airspeed (touchdown plus 5 knots), firm with touchdown mandatory before 200 feet of runway had passed. Aggressive reverse and braking was normal. Most C-130 runways were less than 3,500 feet long. Landing was always a thrill. At major airfields with long runways, turnoff was usually at the first available.

On the ground, the offloads were rapid, often without engine shutdown. Sometimes the loadmaster pushed cargo pallets off while slowly taxiing. As a safety officer, I was saturated with issues but realized that safety in Southeast Asia was really a "learn to live with danger" program. The training, wariness, and discipline required of the flight and ground crews was the highest caliber.

Departures from small airstrips were usually announced over a common frequency and the nearest tactical radar was contacted once airborne.

At a major airfield like Saigon, pilots often flew general aviation traffic patterns when VFR or arranged an acceptable way of getting in line on final with the tower.

The Tan Son Nhut tower controllers were not military, but Vietnamese civilians. They were unbelievably good, sometimes hard to understand, but unflappable. They got the job done. Taxiing to the ramp was also without much direction, even though some ramps were multidirectional but only single lane. Aircraft were required to have marshals only when closer than 10 feet to objects with which they might collide. This often meant that small Army airplanes would try to taxi under a parked airplane’s wing. This was all part of the battle for democracy and freedom. Surprisingly few mishaps occurred.

After observing the special VFR operation in flight, I had to become familiar with the ground support sites that kept their eyes on things. I first visited the GCA (ground-directed radar azimuth and height-controlled approaches similar to those available in the 1949 Berlin Airlift) trailer, which was parked near the base of the tower at Tan Son Nhut. Its old orange and black scopes looked like bowls of popcorn with all the radar returns. From this cacophony, the controllers were able to get a selected target on the runway about every 3 minutes, using as many as four controllers. They also vectored ILS-equipped aircraft onto final for about one landing per minute. I decided to see if any flightcrew members would like to see how their fates were being handled professionally by these outstanding airmen and arranged to bring out small groups in the ensuing months.

When socked in, Saigon had both ILS and ground-controlled radar precision approaches (GCA) to parallel runways that were less than 4,500 feet apart. Not all major airports had ILS, so many airline crews had to become trained in the GCAs in which a constantly talking controller provided both heading and altitude verbal instructions. Many military pilots were qualified down to 100 feet for GCAs and only 200 feet and half a mile for ILS. Many tactical aircraft were not ILS-equipped.

Next I visited the tower, where I met the USAF guest controller on duty and observed the tower in action. If absolutely necessary, such as in an emergency and when requested, a USAF controller was allowed to handle your flight only, not the whole airfield operation. He was my tour guide while the two Vietnamese controllers remained busy with airfield operations.

I noted some paratroop training drops just north of the airfield and could also see traffic going into Ben Hoa, another major airfield just 19 miles north. I asked my tour guide how they shared the airspace and how he advised Ben Hoa of traffic heading their way. He showed me a standard-issue rotary dial phone and pointed to the phone number list on the wall. They had no dedicated line, only routine telephone service to other towers or approach control facilities. All departure clearances were steered south to avoid conflicts with Ben Hoa.

The tower crew gave me a card with the special phone numbers so I could call in case of emergency. The card came in very handy months later when one of our aircraft had to land on a foamed runway with a partial landing gear failure and a load of rockets aboard. With the help of the U.S. military tower operator, the Vietnamese controllers agreed to let the aircraft land on the last third of the active runway while continuing to keep the rest of the runway open for heavy expected traffic. The controllers ran the show like it was an aircraft carrier deck. The crippled C-130 landed without catching fire, was evacuated quickly, and was removed from the runway in a little more than an hour. A war was going on.

I also visited the tactical radar site, called Paris Control, and learned the radar was vintage Korea and picked up targets only four times a minute.

While I was there, I spent some time asking what would happen if someone wanted to report a near miss. They showed me their green in-theater form, which I could submit for an in-house investigation. I asked what was wrong with a pilot submitting a hazard report (like an ASRS report) for investigation, and they showed me their regs that required a "higher headquarters" inquiry. I agreed to triage any near-miss and hazard reports and submit the "appropriate" form if military air traffic control was involved.

I also asked if there was such a thing as civilian air traffic control for IFR and where it was located. This turned out to be the biggest revelation of the war for me.

Paris Control told me the local FAA facility was just a few buildings away from my flight line office. I found the FAA folks next to a little BX barbershop in a small room with one repeater radar scope using the same 4-rpm antenna as Paris.

The site had four American controllers assigned, but no Vietnamese. All they could do was try to find the target on the scope and advise those listening on frequency of nearby traffic. They assigned altitudes based on other known IFR traffic only. They had 100 percent coverage of South Vietnam through arrangements with other traffic control agencies, but actually provided no traditional traffic separation services by then-typical U.S. standards.

I asked if the airlines and the flight crews of military aircraft from the Untied States were aware of this. They told me that the flight crews of all Military Airlift Command and U.S. civilian aircraft, those required to file under IFR, coming into Vietnam must be briefed before arrival at special locations. I had attended these briefings many times, but never dreamed that IFR, in reality, was not the practical, safe way to fly in wartime Vietnam.

One of the briefing items at these offshore installations was a short definition of the term, "Will you accept vectors through arty [artillery]?" When receiving arrival vectors over land below 6,500 feet, controllers were required to ask that question of all IFR aircraft.

Early in the war, stateside crews who expected to fly "in country" were required to practice an approach to a combat zone airport: the landing gear and flaps were set up at approach speed at 6,500 feet. When the runway approach end disappeared below the nose, the throttles went to idle, speed brakes deployed, and pilots nosed over, aiming at the runway threshold.

This worked—a landing was possible—but the descent was not passenger-friendly. It also did not work in the standard "in country" cloudy weather.

We also were trained to come in over the field at 1,500 feet and pitch out like many normal fighter arrivals. This, too, was fun but not very practical for some of us more elderly pilots or cumbersome aircraft. All of this was intended to provide minimum exposure to enemy gunfire and allow friendly artillery to continue to fire at Charlie.

The problem was solved by installing special Army tactical FM radios in aircraft assigned to fly in country for a living. Our C-130 crews could talk to artillery units and arrange to fly over their area without being hit by friendly fire. Aircraft flying in from the States were offered "vectors through arty," which eventually, through spin control and the capriciousness of the American language, came to be interpreted as O.K. because it was supposed to be "vectors around arty." Airliners and transpacific aircraft were sometimes, but rarely, hit by gunfire while approaching or departing Vietnamese airfields. It was almost safe enough.

One of my many duties as safety officer was to investigate safety hazard reports, similar to the ASAPs now in experimental use by a few airlines. Military regs guaranteed anonymity and nonretribution for the submittors. I was very handy to the crew dispatch area, and rarely did a day go by that one was not dropped off at ops or on my desk.

I finally made a deal with the crews. If I could get a satisfactory response for the problem in 24 hours, no one would have to submit paperwork. Our unit had only one, nonelectric typewriter. My reports were handwritten with a carbon paper copy. I had 144 investigations that required written response in my file drawer when I turned over my job to my replacement after 11 months. I catalogued another 180 that were answered in 24 hours without formal paperwork.

I recall only four or five big investigations involving ATC. One involved a note on the letdown plate at Danang warning pilots not to pass a radial 5 degrees beyond the final approach course when being vectored to ILS final. One of our crews in clouds couldn’t get a word in edgewise with continuous ATC transmissions and went past the radial. Approach finally noticed it and gave him an emergency late turn back to final.

The pilot submitted a report. It resulted in more definitive wording allowing pilots to turn without verbal clearance automatically. Monkey Mountain, which was very hard rock and full of caves with snipers, was only a few miles away. ATC was very willing to see the pilot’s point of view on this one. It took only phone call coordination, a temporary NOTAM, and a week to change the approach plate. No paper hazard report and HHQ investigation were necessary.

Another incident involved a departure from Saigon. A thunderstorm was off the end of the runway, and a C-133 (huge Douglas turboprop) was departing for the Philippines. Instead of turning left, the pilot turned right to depart north of the field at pilot’s discretion to avoid the storm.

The tower had not arranged for him to penetrate Ben Hoa’s airspace to the north and got on the phone right away. The line was busy.

Meanwhile, one of our C-130s had arranged to descend in Ben Hoa’s airspace through clouds. While in and out of clouds, descending at a rapid rate, our C-130 crew visually spotted the C-133 at very close range. Both crews submitted near-miss hazard reports, the C-133 at the next destination. The cat was out of the bag.

Higher headquarters loaded up an airplane in the States and picked up some more investigators in Hawaii. Within 24 hours, the almost-safe-enough system was under extreme scrutiny.

My safety counterpart in Division Headquarters had to give a presentation on why IFR operations would not be safer. His response was simple: No aircraft would move. With the primitive IFR capability available, gridlock was already there.

In the course of the investigation, HHQ found out they needed to clarify what "vectors through arty" meant and promised to beef up the ATC capability in the theater. The theater commander thanked the team for its efforts and admonished it to ensure the next war had better tools for air traffic control. Today we have AWACS, J-Stars, ABCCC aircraft for airborne traffic control, and radars with transistors instead of vacuum tubes in some places.

During my tour, a huge operation named Lamson 719 was launched. We were to airlift thousands of South Vietnamese (ARVN) troops to Khe Sanh, a small mountaintop outpost on the Laotian boarder near the Ho Chi Minh Trail. Khe Sanh was the site of a bloody and heroic battle earlier in the war and was considered strategically very important.

The airfield had operated mainly for helicopters, but now was being reopened for airplanes needing at least 3,000 feet for landing. Situated on a mountaintop accessible by dirt road, the site had room for one runway, a parallel taxiway, a heliport, and a small cargo ramp. The commander and I went up with a team to assess the situation. We landed on a rough-clay, recently graded runway.

The Army had three young air traffic controllers standing on top of cargo boxes supported by sand bags. The most senior was a junior sergeant. They had no capability to land aircraft in weather. Khe Sanh was notorious for low ceilings and rain. IFR operations had to be considered.

Before we returned to Saigon, a mobile Air Force trailer with Tracon capabilities was ordered flown in from the Philippines. The runway was also covered with steel planking.

A week later, I returned to see a fully operational airfield with some airplanes also landing on the parallel taxiway. On arrival, Tracon held us in a stack, descended us in sequence, and gave us a reliable expected approach time.

Later, as we taxied out for departure with the rear ramp open for cooling, we were No. 3 for takeoff. The loadmaster told us some troops were coming out of the jungle and climbing on board. An ARVN (South Vietnamese) unit hopped on and strapped themselves to the floor while we awaited clearance for takeoff. They were really happy when they found out we were headed for Saigon. They expected to be back in the battle in 2 days.

In less than a month, the mission was said to be accomplished. The Ho Chi Minh Trail had been shut down for a while. With victory declared, they loaded up the troops, the wounded, and the equipment and quickly flew out of that place. The Tracon in a trailer went back to the Philippines to get ready for the next call. The airfield reverted to a small VFR heliport with just a few aircraft flights per day.

A month or so later, I got out of that place, too. During my tour, I had the great good fortune to have investigated only two minor Class B accidents in which no flightcrew members were even injured and both aircraft returned to action. With the help of a free flow of dialogue by all parties involved in aviation safety, especially the flight crews, special VFR at that time was a memorable success.

As I look back now, the system was adequate only because there was a collaborative effort. Aircraft had no onboard weather radar, no glass cockpits, no head-up displays, no TCAS, no altitude-reporting transponders, no satellite navigational technology, no digital radios, no huge ATC centers with warning systems, no doppler radar, no advanced GPWS with terrain displays, no CAT 3 approaches, no MSAW, no cloud-penetrating visual aids, no requirement to fly in clouds for prolonged periods under special VFR, no conflict-resolving computers, no sophisticated automation, and on and on. Safe flight under those loose rules was possible in Southeast Asia only because of four sets of weary eyeballs, three talking radios, ad hoc navigation aids, portable radar sights, dedicated support, forgiving rules, and highly skilled, dedicated personnel throughout the system. Some days, it seemed like an act of Buddha.

Today’s ATC system in the United States undoubtedly needs to be improved to keep up with the demands of transportation requirements. United Airlines reports up to half a year of lost time due to flow control alone. Losses due to delays and cancellations are increasing. Capt. Duane E. Woerth, president of ALPA, agrees that the U.S. ATC system is "definitely under stress." A few enroute thunderstorms can cause "total paralysis." But the system of "Special VFR" that worked in a war zone 30 years ago is not the answer for U.S. airways today.

Both flight crews and air traffic controllers are being provided the information management tools that will allow a near-future, on-time, even safer air travel system. Many research and analysis projects are currently ongoing. Some airports and airlines are testing new technology that is competing to provide a visual "virtual VFR" capability that will allow more aircraft into less space comfortably, on a see-and-be-seen flight deck display basis both on airport surfaces and enroute.

Solutions must not produce unintended results. They must be economical, user-friendly, economically installed and retrofitted, and easily updated and improved. The cost of the best, most-accepted universal system could easily pay for itself in both safety and economic terms. The technology exists, but the possibility of paralysis by analysis by the regulatory authorities is ever present.

Capt. Tom Duke logged more than 11,400 hours in military and Part 121 four-engine transports. A former Director of Safety of the U.S. Air Force Reserve, he has been a researcher for the NTSB. He often writes for Air Line Pilot.