February 1, 2009
By Barry Schiff
Barry Schiff has written more than 1,500 aviation articles.
When working on my instrument rating in 1956, I had to execute instrument approaches using four-course, low-frequency ranges. Although they served their purpose, I am thankful that these sadistic procedures and radio aids have been superseded by modern technology. The good news, though, was that only a low-frequency receiver was required. It was no more complex than a conventional AM receiver. The bad news was the punishment administered incessantly through the headphones while struggling to interpret the aural signals against a background of static and hash. Orientation often was confusing, frustrating, and created mental anguish.
I also learned to execute the much easier ground-controlled approach or GCA. Later called PAR (precision approach radar), these involved simply following a controller’s heading and descent instructions to decision height. Although PARs are relics, they are still in use at many military bases. In some cases, a civilian pilot can obtain permission to make a PAR approach—especially when controllers need practice to maintain proficiency—but be prepared to go around at minimums. Landing at an Air Force or Navy base without permission can result in inhospitable treatment.
When I joined TWA in 1964, I thought I had seen the last of the ground-controlled approach. Not so. While heading toward Fiumicino Airport near the end of a red-eye passenger flight from New York to Rome in a Boeing 707, we were advised that the ILS was “Oscar Sierra” (out of service), and that we were to expect a “radar-guided” (PAR) approach. The “Fiume” weather was reported as 200-foot overcast and a half-mile visibility.
I was a new first officer, and neither I nor the captain had executed a radar approach for years. We agreed that this was no big deal. All we had to do was follow the controller’s instructions. The approach controller vectored us to final approach and handed us over to the final controller, who would provide lateral and vertical guidance to decision height where we would hopefully see enough of the runway to make a safe landing.
In preparation for final approach, the radar controller issued the standard admonition, “TWA Eight-Four-Zero, if no transmissions are received for a period of 10 seconds, execute a missed approach.” Instructions for the miss were provided. The reason was obvious. A lengthy pause in communications could signify radio failure, and it would be dangerous to continue descending at such a time. (In the United States, a 15-second period of silence is the maximum allowable.)
The final controller began his litany, “TWA Eight-Four-Zero, turn left heading 340. Glide path intercept in two miles. Do not acknowledge further transmissions.” Pause. “Turn further left 338. Prepare to begin descent in one mile.”
We lowered the landing gear, extended the flaps to 50 degrees, turned on the rudder pump, and reduced airspeed to VREF plus 5 knots.
“TWA Eight-Four-Zero, turn back right heading 340. Begin normal descent. Correcting nicely.”
A normal descent consists of the sink rate needed to descend along a three-degree glide slope. This can be determined from an ILS approach chart by referring to the “sink rate vs. groundspeed table.” Or you can use this rule of thumb: add a zero to groundspeed and halve the result. A three-degree descent profile and a groundspeed of 120 knots, therefore, require a sink rate of about 600 fpm.
The final controller continued, “TWA Eight-Four-Zero, turn left heading 340. Going slightly low on the glide slope, decrease sink rate. On course; turn right 342. On glide slope; resume normal descent. Tower clears you to land Runway 34 Right.”
At 500 feet agl and still descending, the radio got quiet for too long. No instructions, no nothing. The captain, I knew, was mentally preparing for the possibility of a miss.
Four hundred feet. Still nothing. We were only 200 feet above minimums and sinking. I grabbed the mic and anxiously asked, “Fiume Radar, TWA Eight-Four-Zero. Are you there? Are we OK?”
“TWA Eight-Four-Zero, you’re doing-a just-a fine. Don’t touch-a nothing.”
Such was the nonchalance of Roma Radar.
Italian controllers were a breed of their own. A year or so later we found ourselves at the end of a long line of departing aircraft. Departure radar, we were advised, was “Oscar Sierra” (something was always “Oscar Sierra” in Italy in those days) and aircraft were allowed to depart in only five-minute intervals.
Pilots were becoming impatient at the snail-like progress of the departure queue. A few aircraft had been waiting so long that they had to return to their gates for refueling. Finally, one pilot, an American (in the Pan Am 707 immediately ahead of us, we suspected) transmitted, “C’mon Fiume. How about moving this parade a little faster?”
The Italian controller responded, “All aircraft on-a-da ground at Fiumicino, ground control going closed.” Subsequent calls to Ground were unanswered and surface traffic came to an immediate halt.
Thirty minutes later, the controller came back on the air and said, “All right, you guys. Now tell-a-me. Who’s-a-da boss?”
Safety and Education,
Pilot Training and Certification,
FAA Information and Services
The NTSB has organized a safety seminar May 10 to focus on aerodynamic stalls and loss of control, a leading cause of general aviation fatalities.
According to the most recent Joseph T. Nall Report, in 2010 there were 43 accidents involving weather, and 28 of them were fatal. In fact, weather accidents are the most consistently fatal types of accidents.
There is another aircraft nearby, and its pilot is going to unusual lengths to keep you in sight.
VOLUNTEER AT AN AOPA FLY-IN NEAR YOU!
SHARE YOUR PASSION. VOLUNTEER AT AN AOPA FLY-IN. CLICK TO LEARN MORE >>>
VOLUNTEER LOCALLY AT AOPA FLY-IN! CLICK TO LEARN MORE >>>
BE A PART OF THE FLY-IN VOLUNTEER CREW! CLICK TO LEARN MORE >>>