Pilot/controller responsibilities

July 1, 1999

When it comes to air traffic control services, there are times when it may be difficult to determine who is responsible for what. The Aeronautical Information Manual has a complete section devoted to the division and sharing of responsibilities. Reading about it is a bit dry — right up until the time when the safety of flight depends upon clear interpretations.

One of the best rules puts the authority and the responsibility on those who have the most at stake — the pilots. FAR 91.3 says that the pilot in command is directly responsible for, and is the final authority for the safe operation of, an aircraft. In an emergency pilots can deviate from any rule as needed. That does not mean that you will necessarily escape legal sanctions from the FAA if the emergency is of your own making. Obviously, if you need to break a rule to survive — do it! Deals involving the grim reaper are more permanent than those involving the FAA legal staff and you frequently can negotiate with the feds.

"The air traffic controller is responsible to give first priority to the separation of aircraft and to the issuance of radar safety alerts...." Other functions are performed on a time-available basis. "In order to maintain a safe and efficient air traffic system, it is necessary that each party fulfill their responsibilities to the fullest. The responsibilities of the pilot and the controller intentionally overlap in many areas providing a degree of redundancy. Should one or the other fail in any manner, this overlapping responsibility is expected to compensate, in many cases, for failures that may affect safety." We work as a team to make safe flight possible. In sports, a team member always backs up a teammate so that if he or she misses the ball someone else is there to save the play.

The need to acknowledge receipt and understanding of an air traffic clearance seems self-evident. However, one doesn't have to listen for long on any busy frequency to hear at least a few pilots simply "roger" a complex clearance. This unfortunately eliminates a critical safeguard — having the controller verify that the pilot did receive the correct message.

Recently, the FAA put out an interpretative rule that seeks to hold pilots fully accountable for clearances that they misheard or misunderstood. Under this interpretation, if the controller clears a flight to 5,000 and the pilot responds by reading back "9,000," ATC would have no legal responsibility to correct the error (see " Pilot Counsel: Questioning Clearances," June Pilot). This is flawed logic from both a legal and moral standpoint. AOPA and the AOPA Air Safety Foundation have responded vigorously to this absurd change. It has no place in our cooperative system, and by the time you read this, I hope that it is no more than an obscure paragraph in the Federal Register that was summarily dismissed.

Sometimes, though, it works the other way. Case in point: On a recent IMC day a controller cleared a flight down to 4,000 feet and provided a turn to avoid a traffic conflict. The pilot acknowledged by repeating the heading and — not expecting the descent since he was in cruise at 5,000 — asked, "You want me down to 4,000?" To which the controller responded, "Roger, maintain 5,000." The pilot then asked, "Which is it — 4,000 or 5,000?" At this point a supervisory controller overrode the controller trainee and confirmed that the proper altitude was indeed 4,000. The system worked as intended, but a simple "roger" wouldn't have allowed the verification.

The AIM states that controllers should "ensure that readbacks by the pilot of altitude, heading, and other items are correct. If incorrect, distorted, or incomplete, [the controller] makes corrections as appropriate." Pilots should do the same in verifying instructions.

One of the handiest approaches in the instrument pilot's bag of tricks is the contact approach. It is a legal and useful shortcut, but there is a string attached. The contact approach allows a pilot to deviate from a published instrument approach procedure and proceed on his own initiative by navigating to the airport where the visibility is reported to be at least one mile. The pilot must have ground contact (hence the name) and remain clear of the clouds, but what is important is that he becomes responsible for his own terrain separation.

The controller is required to keep the flight clear of other IFR and special VFR aircraft and to allow the pilot back into the IFR system if ground contact cannot be maintained. ATC cannot suggest or even mention this approach to pilots. You must request it and thus take on the responsibility. A controller with radar coverage may give you a low altitude warning if he senses that the flight is about to contact terra firma, but that is your responsibility. In many cases a flight will be below radar coverage. This procedure is not recommended at night for obvious reasons.

Radar vectors are always popular since someone else is now doing the navigating and all the pilot has to do is comply with heading and altitude assignments. But the pilot is responsible for questioning any heading or altitude believed to be incorrect. If you're operating VFR and a vector will put the flight too close to a cloud or an obstruction, you're obligated to speak up. It doesn't happen often, but occasionally on a VFR vector the controller will get busy and forget about you. Guess who shares in the responsibility?

See and avoid in VFR conditions makes the pilot responsible for not hitting other traffic, terrain, or obstructions. As the old joke goes, you're first to the accident scene, so why not be involved? The controller will provide traffic information on a workload-permitting basis and issue safety alerts regarding terrain, obstructions, or proximity to other aircraft. So how do you know whether your controller is up to his eyeballs in other work, meaning that you are essentially on your own regarding other VFR traffic? It's hard to tell because even on a quiet frequency the controller may be working another sector where you don't hear the other aircraft. ATC's Radar Traffic Information Service is sometimes referred to as flight following or VFR advisory service. IFR aircraft will normally be provided with traffic information on other IFR aircraft. However, VFR aircraft may not always be advised of conflicting traffic.

The closest encounter I've had with another aircraft occurred while receiving VFR traffic advisories just beyond the outer ring of Class C airspace. The bogey approached from our two o'clock position and slightly low. That slight difference in altitude is what saved both of us. As a passenger on the right side, I caught a glimpse of something flashing below the Piper Arrow that we were flying. It was over in less than a second, and a Beech Bonanza emerged behind the left wing. We advised ATC, who simply "rogered," and then the Bonanza pilot came up on frequency requesting Class C clearance. Who was responsible? The pilots of both VFR aircraft — the service does not relieve pilots in VFR conditions from see-and-avoid responsibilities.

I've been having a discussion with a controller who claims that a control tower does not "separate" traffic in Class D airspace, but just sequences them in VFR conditions. That's true as long as one pilot has the other aircraft in sight. But if you're unable to spot the other aircraft — which is sometimes the case because of lighting, haze, ground clutter, dirty windshield, poor eyeglasses, stealth paint jobs, aircraft structure, pilot disorientation, and distraction, etc. — who's responsible?

The AIM says "If instructed by ATC to follow another aircraft or to provide visual separation from it, promptly notify the controller if you lose sight of that aircraft, are unable to maintain continued visual contact with it, or cannot accept responsibility for your own separation for any reason." If any of these conditions apply, the AIM says that the controller should not use visual separation. The NTSB has occasionally cited ATC for poor procedure when VFR aircraft have collided in Class D airspace, but not very often. If a pilot says that he or she has the traffic, the monkey is on his or her back to follow the leader and to avoid wake turbulence as needed.

Poorly executed instrument departures periodically seem to make headlines, but obviously the pilot is in the best position to decide whether the flight can depart visually at a nontowered airport or whether a specific departure procedure is required. Airports with instrument approaches will have departure procedures if there is an obstruction or terrain that meets the criteria. The procedure is cryptically described in small print. Be very sure to understand what you think the writer meant. It means the difference between a successful flight and a sudden stop. When ATC picks up the flight on radar, also confirm that you concur with the guidance. If the controller gives you a bum steer — which is unlikely but possible — ask the question. It is part of the shared responsibility concept.

Minimum fuel advisories are something that pilots must communicate when the fuel supply is low enough that the flight cannot accept any undue delay. The AIM says that this is not an emergency, but merely an advisory to controllers that an emergency may develop if any significant delay develops. This will not provide for traffic priority and if that becomes necessary, the pilot should declare an emergency. The controllers are responsible for passing the advisory along to subsequent controllers so that they can be alert to any delay that will create a problem.

Pilots and ATC make a very good team, and the safety record is proof of that. Pilots are at greater risk, however, and we should take a very active part in holding up our part of the bargain.


See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.