How much power does and ATC Controller possess?

[Calvin Waterbury]

I was reading this thread and it provoked a question...

I know that a controller has almost god-like authority over his/her airspace, but do they have the authority to direct a turbojet aircraft to use a specifically stated non-turbojet SID/STAR?

[Anthony Santanastaso]

Hi Calvin,

As a general response to your question, there is a shared responsibility between the pilot and ATC over the operation of each flight; however, it is the Pilot-in-Command that ultimately has the final authority in regards to safety. If a pilot cannot comply with ATC because doing so comprises the safe operation of their aircraft, they can refuse or deny the instruction.

Please do not misunderstand me, however. Pilot deviations are a big deal as they require the pilot to justify their refussal to comply with ATC instructions. A great example of a misuse of PIC authority is when an American Airlines flight flying into JFK decalred an "emergency" because they didn't want to manage the crosswind landing on Runway 22L while Runway 31L was closed due to construction. The pilot was adament that they wanted Runway 31R (which, although it wasn't closed, would disrupt the entire flow of operations into and out of JFK) to the point that it became clear that the "emergency" was just a way to get around having to land on the preferred runway in use. The crosswind component for the pilot's type aircraft was well within limitations, so it became more of a personal matter. It is my understanding that the "emergency" was looked into after it had occured.

I do not think that it is appropriate to say that ATC has god-like power; however, you must understand that they have the advantageous vantage point of being able to observe the big picture. A departing pilot may not understand why they have to be held at 5,000 for 20 miles, but little do they know that Approach Control is working a constant stream of arrivals that overfly the departure's flight path descending to only 1,000 feet of vertical separation.

Under certain circumstances, you as the PIC have the right to ask "why" certain decisions are being made. A perfect example is if you are asked to "Line Up and Wait" on the active runway and a minute or more have passed after the instruction was given. In the interest of safety and situational awareness, it would behoove you to question why you are remaining in position on the active runway. There is always a chance that the controller lost track of the sequence and literally forgot about you. It doesn't happen often, but it is a possibility.

Here is another questionable scenario. What if you are flying heading 270 and your are told to "Turn left heading 300." Sounds odd, right? Did the controller actually intend to turn me to the left 330 degrees instead of the much more sensible 30 degree right turn? This would be an acceptable circumstance to question, or verify, the instruction. Controllers will often cut to the chase and provide clarification by adding "the long way around" when they indeed want you to turn a direction opposite than the shortest.

If you would like to learn more about pilot/controller responsibilities, please check out the following article that was published by AOPA:
http://www.aopa.org/asf/asfarticles/sp9907.html

I hope that this helps to answer your question.

Blue skies,

Anthony

[Calvin Waterbury]

Thanks Anthony,

Just so you know, "god-like powers" was not intended to be any kind of a jab. I t was only a description within the context of trying to understand what authority do controllers.

Excellent explanation; however, it did not address the specifics of the OP. Perhaps I should have asked the question differently.

Take Two!...

Specifically, do controllers have the authority to assign specifically identified "non-turbojet" SIDs/STARs to slower turbojet aircraft?

[Keith Smith]

My guess is that the notes would preclude a pilot from filing a STAR that ATC normally doesn't want them flying (for flow/separation reasons). An example would be a turboprop flying the RIIVR2 arrival, which would normally cause sequencing headaches. Similarly, if a fast jet wanted to fly the KIMMO2 into LAX, they could have sequencing problems with turboprops on that arrival.

However, if a slow moving jet (flying at close to turboprop speeds) shows up, then it makes sense that ATC could assign a STAR that is generally for turboprop aircraft, as long as the aircraft has the navigation equipment required to fly the STAR. That would be ATC's call as they have the big picture.

[Keith Smith]

I was watching a video of my arrival into ATL a few minutes ago and noticed a case where the controller assigned me a STAR that was published as being for jets and turboprops only:
http://www.youtube.com/watch?v=Qh9o1S5V9Qc (around the 1:20 mark). As you can see, it's a bit of a non-event.

[Calvin Waterbury]

I was watching a video of my arrival into ATL a few minutes ago and noticed a case where the controller assigned me a STAR that was published as being for jets and turboprops only:
http://www.youtube.com/watch?v=Qh9o1S5V9Qc (around the 1:20 mark). As you can see, it's a bit of a non-event.

Conundrum concluded!

[Keith Smith]

correction: 1:20 mark.

[Daddy O]

The official regs say that the pilot has ultimate authority over the craft, even over ATC. However, if you refusae an order from ATC, you better have a good reason when you land. I've had to refuse instructions both on the ground and in the air. Both times they were guiding me in front of heavy traffic. Simple controller errors.

As far as the approaches and departures, how much real world negotiation is there? Is it common to hear wrangling from pilots trying to obtain a different approach? KSNA has some scary departures, do RW IFR pilots just take the departure handed them or is ATC flexible enough to permit specific approaches when the volume permits?

[Anthony Santanastaso]

The official regs say that the pilot has ultimate authority over the craft, even over ATC. However, if you refusae an order from ATC, you better have a good reason when you land. I've had to refuse instructions both on the ground and in the air. Both times they were guiding me in front of heavy traffic. Simple controller errors.

As far as the approaches and departures, how much real world negotiation is there? Is it common to hear wrangling from pilots trying to obtain a different approach? KSNA has some scary departures, do RW IFR pilots just take the departure handed them or is ATC flexible enough to permit specific approaches when the volume permits?

I can't say that I have ever really experienced wrangling on the radio regarding IAPs except for the AAL exchange I quoted in my first post, but I would imagine that it doesn't happy too often. ATC assignments are not meant to "get you" or restrict your ability to fly. By that I mean it isn't like ATC will unnecessarily reject your reasonable requests "just because." ATC issues control instructions based upon known traffic conditions in order to safely and expeditiously separate you from other traffic. If your suggestion will achieve the same objective, I can't see why it wouldn't be approved. However, if you are asking for something that may compromise the flow as ATC can observe by looking at the big picture, then either you'll have to stick with the original assignment, accept an alternative solution, or wait until such time that ATC can accommodate your request (e.g., hold on the ground or in the air and/or be put in the back of the sequence).

Section 5 of AIM states several understood Pilot/Controller Roles and Responsibilities that may be pertinent to your question. Here is one regarding the role of ATC:

The air traffic controller is responsible to give first priority to the separation of aircraft and to the issuance of radar safety alerts, second priority to other services that are required, but do not involve separation of aircraft and third priority to additional services to the extent possible.

I think when it comes down to it, if you have a reasonable request that will not negatively effect the flow and separation of traffic, and you sound like you know what you are doing, then ATC will accept it.

If you are rejected, or told unable due to a reason, I wouldn't bicker on the frequency. Either continue the flight as per your training or do not fly at all. Then, when you have an opportunity, call the facility and engage in an educational and constructive conversation where you can learn more about the situation.

I highly recommend everyone communicating with ATC facilities and even scheduling visits for a tour. You will learn a lot - and it's fun! Also, be on the lookout for such programs like Operation Raincheck as they are seminars that are often presented at ATC facilities in the interest of improving the relationship and understanding of how ATC works. There is actually one scheduled on 3/23 at N90.

For more information, check out http://www.faasafety.gov/.

[Keith Smith]

There is no reason that I can think of why a piston pilot should reject a STAR that is charted as being for turboprop/jet aircraft (unless it has nav equipment requirements that you can't meet). There is nothing unsafe about flying the STAR, so if you say "unable" simply because it's a jet/turboprop STAR and you think you're not allowed to fly it, or you might get hit by a jet, or you might be in the way of the traffic, etc...then ALL of those are very poor reasons for not flying the STAR. If ATC is asking you to fly it, then they have the big picture and a plan and will issue instructions that will ensure separation. In my case, I was kept 1000ft below the arrival stream which were all doing 250kias+. I was later merged into the arrival stream while doing 160-180kias, the same speeds they were being reduced to.