October 9, 2008 Vague Vectors

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by	Tom Gilmore

About the Author ... Tom Gilmore is an instrument flight instructor and a regular contributor to IFR Refresher. He lives in Stuart, Fla. Why the Words Matter As is the case with so much of the FARs and instrument procedures, the current approach phraseology is an example of a rule written in the blood of an accident. In this case, it was the crash of TWA 514 on Dec. 1, 1974, killing all aboard. The 727 was en route to what was then National Airport but, because of high winds, it diverted to nearby Dulles International. When the aircraft was cleared for the VOR/DME 12, the crew descended too soon and struck high terrain near Berryville, Va. The NTSB's investigation revealed the controller's approach clearance was ambiguous and the chart lacked consistent detail on minimum altitudes. As a result, the NTSB recommended changes in ATC phraseology to clarify whether radar is in use or not, thus the phrase "Expect radar vectors" came into standard use. th NTSB further recommended a standard lexicon for pilots and controllers, which morphed into what we know as the Pilot/Controller Glossary. Yet confusion persists. If ATC doesn't say, "Expect radar vectors," the pilot is expected to know the approach will be handled as a non-radar procedure, or "full approach." What controllers don't say -- nor are they required to -- is, "Radar service unavailable, expect the full approach." But the controller's manual (FAA Order 7110.65) does specify phraseology for both vectors and non-radar approach clearances. Non-radar clearances won't include the phrase "Expect vectors" and you should listen for this. Second, listen for a phrase like this: "Cross Westminster at or above 3000. Cleared VOR 34 approach." The phraseology used in the incident described in the main text was close, but ... not exactly. Unfortunately, almost 35 years after TWA 514, we still speak in code. Both pilots and controllers are expected to know it, even if they often don't.

Flying the System

Pilots and controllers rely on each other to communicate unambiguously, especially when working together to complete an instrument approach. The rules of the game are supposed to be clear, yet somehow pilots and controllers continue to clash when an aircraft is in position to join the final approach course straight-in without flying a published procedure-turn holding pattern. Are you being vectored or should you fly the hold entry?

There has apparently been so much confusion in this area that AOPA Air Safety Foundation created an online safety course devoted to unlocking the mystery. The course, "IFR Chart Challenge: VOR Approach," describes an incident that occurred on the VOR approach to Runway 34 at the Carroll County Regional Airport in Westminster, Md., (DMW). The aircraft, a Cessna 182, was located southwest of the airport approaching the Westminster VOR (EMI) and had been cleared for the approach. The Potomac Approach controller issued the following instruction: "Cessna 611MS, 10 miles from Westminster. Proceed direct Westminster, maintain 3000 until established. Cleared VOR Runway 34 approach Westminster." At the time, the aircraft was located on the 190-degree radial, 10 miles southwest of EMI, heading 010 degrees at 3000 feet.

The Cessna was approaching the VOR from the southwest, on the 190-degree radial, and the controller's approach clearance was, "Proceed direct Westminster, maintain 3000 until established. Cleared VOR Runway 34 approach, Westminster." The AIM is clear on what's required and the pilot did exactly what was specified, yet this caught the Approach controller by surprise. What would you do in this situation?

What would you have expected to do if you were in the left seat? (A) Perform the published course reversal; or (B) join the final approach course and continue straight in? If you chose answer (A), you are correct. The Skylane pilot did too, based on how he interpreted the ATC instructions. He chose to fly direct to EMI and executed the full approach with a direct entry to the holding pattern to get established on the final approach course. After making the course reversal turn and established on final outside the FAF, he expected to descend to the published 2900 feet.

This, however, is not what the controller expected. After the Skylane pilot made the turn to the outbound course, he got an earful and later alleged that the controller said, "I did not clear you for the procedure turn." This is a situation when the controller expected a certain reaction, but the pilot had other plans.

AIM 5-4-9 says that the holding pattern or procedure turn must be followed except when radar vectoring is provided or "NoPT" is depicted in the procedure. The Pilot/Controller Glossary defines "radar vectoring" as the "provision of navigational guidance to aircraft in the form of specific headings, based on the use of radar." The C182 was instructed to proceed direct to the VOR, not to fly a heading to join the final course.

A full investigation was launched with the Potomac TRACON after the pilot objected to the fact that the radar controller was upset with the pilot for making the procedure turn. The investigation proved the pilot correct, especially because he wasn't cleared to descend from his last assigned altitude of 3000 feet to the FAF altitude of 2900 feet. In addition, he hadn't heard "cleared straight-in" at any time from ATC.

ATC might clear a pilot for an approach when the pilot expects she will be getting vectors to final. A pilot might also believe she's cleared for a straight-in, especially if she's nearly aligned with the final course and at or near the FAF altitude.

Another source of confusion can occur when the controller instructs a pilot to intercept the final approach course outside the FAF and then makes the approach clearance and descent conditional on that intercept. In this situation, no course reversal is expected.

This was common in some locations before radar was installed, when a remote facility was directing the aircraft but did not have the capability to monitor the approach at the lower FAF altitude. It is obviously best to be sure both pilot and ATC are on the same page when conducting any instrument approach.

How can a pilot know what is the correct procedure? If ATC tells you, "This will be vectors for the [specified] approach," or "This will be vectors to final," or "Intercept the final approach course and fly it inbound," then you're cleared straight in.

However, if all you hear is, "Cleared for the approach," fly the full approach as published. If there's any doubt, query ATC to clear it up. The last thing any pilot wants in the cockpit is confusion when you are focused on making a successful instrument approach, especially if it may have to be flown to minimums. The exchange between pilot and controller has to be clear and concise. There's no room for not knowing the other guy's intentions.