91.215 "deviations"

[minitour]

okay...so who has the authority to make a decision on what "officially counts" as a request for a deviation?

-mini

 

[DX Rick]

Do you mean during the "deviation" or afterwards?

During, obviously the PIC. On the ground, the local FSDO will play Arm Chair Quaterback and figure out if you were in the right or not.

 

[TonyC]

A man carries a legally concealed firearm into a post office. This act is illegal. The postmaster invites the man in, but is unaware of the weapon. Does this constitute an authorization to carry the weapon inside? No, it does not. Neither does merely contacting ATC and receiving a clearance to proceed to point A or B constitute an authorization, implicit or otherwise, to operate with inoperative equipment, or partially inoperative equipment.

The fallacy in this example is the presumption that a pilot could hide the Mode C failure. The pilot in this case is not trying to sneak in the airspace with a malfunction that ATC might not notice. To suggest such fails to recognize that a Mode C failure is likely invisible to the pilot, but a glaring eyesore to the controller.

If you'd like to stick with the Postmaster and Post Office example, consider the same man temporarily confined to a wheelchair due to a leg injury. The fact that he is in the wheelchair is obvious to the Postmaster. If the Postmaster invites the man in the Post Office, the man is not obligated to ask, "Are you sure it's OK? After all, I'm in this wheelchair." If the Postmaster says it's OK to come in and to by stamps from the teller on the left, he's OKing the wheelchair, too. He can't help but notice the wheelchair, and his invitation is not contingent upon the man standing up, leaving the wheelchair, and walking in on two feet.

(Yes, I realize this example fails in that the man in the wheelchair is obviously aware of his wheelchair, whereas the pilot is usually unaware of the Mode C failure until ATC informs him. I tried to stay close to your original example, and that's the best I could do without caffeine.)

The original question of the thread asumes a failure of the Mode C during flight. What is unclear is whether the contact with approach is an "initial" contact coming from a non-radar environment somewhere or a handoff from another controller. Either way, though, the first thing the controller will do (I believe, correct me if I'm wrong) is locate the airplane, and identify it's altitude, heading, and airspeed. If it's a handoff, the controller making the handoff will advise of the Mode C failure. If it's an initial contact, he should immediately notice the absence of altitude encoding. With this knowledge, and knowledge of everything else transpiring in his airspace, he approves or denies requests. He's not going to say, "Cessna 1234YANKEE, cleared blah blah blah as long as you can get your Mode C fixed before you begin" any more than the above Postmaster above is going to say, "Come on in, but you have to leave the wheelchair outside." Any clearance you get assumes you're cleared to do it with the Mode C failure.


Anybody that feels uncomfortable with this assessment should consider including mention of the Mode C failure in each initial contact to minimize uncertainty and confusion. EX: "Aprroach, Cessna 1234YANKEE, Mode C Inop, Request blah blah blah." That should remove all doubt.

 

[midlifeflyer]

okay...so who has the authority to make a decision on what "officially counts" as a request for a deviation?

I think you're trying to make it too complicated. It's really not that difficult. What did you do in elementary school when you needed a "deviation" from remaining in your seat to go to the bathroom? All you did then, and have to do now, is disclose and ask and get a "yes" answer. But instead of "Teacher, I gotta go to the bathroom. Can I?" it's "ATC, I don't have mode C. Can I fly in your airspace anyway," and have them say "Sure." (Unless of course, you simply got up and if the teacher didn't yell "sit down!" you assumed you had permission.)

I teach out of an airport below Denver's Class B, well within the Mode C veil. As training aircraft are wont to do, the transponder crapped out. We found out when Tower told us when we departed. Tower asked what we would do and I told them I'd call Approach for a deviation and call them back to return to the airport if it were denied. Shortened somewhat, after Tower approved a frequency change, the conversation went like this.

"Denver Approach, Cessna 1234X. 3 southeast of Centennial. Negative Transponder."

"Cessna 1234X, Denver Approach. Go ahead."

"Approach. 1234X is enroute to the Centennial practice area 3-5 miles south of Franktown. Out transponder is INOP. Request deviation to operate in the practice area below 9,000 feet."

"Cessna 1234X. Deviation approved. Remain at or below 9,000 feet."

It really is that simple.

 

[minitour]

I think you're trying to make it too complicated...

I don't think so at all...some day a student is going to ask me this question and if I tell him "oh yeah you have to say 'hey here's my problem' to get the approval" and it's wrong, then I'm not doing my job. On the other hand, if I tell him, "if they tell you 'hey your mode c is inop.' and you request a landing or touch and go it's okay" and that's wrong, that is something my student (i.e. me) can be busted on, so that's not cool.

I'm more concerned with the language. I do realize that 91.123(a) means I should be asking if I'm confused with the situation, but I'd really hate to be coming back from a cross country trip and have to say to every controller "hey my mode c isn't working can I stay at 13,000 or do I need to go down to 9?" every few bunch of miles if I don't have to.

-mini

 

[Bernoulli]

Minitour... If at some point during a flight you realize your Mode C is inop (or ATC alerts you to the transponder problem) then simply state to ATC that your mode C is inop and request permission to enter or transition their airspace with the inop mode C. There is no "official word for word statement" . Simply acknowledge the transponder problem and ask for permission to continue into or through their airspace. You should only fly into or through Class A, B, & C airspace with an inop transponder to reach a destination in which the transponder can be fixed. I would not go on a training flight with a known inop transponder and ask for permission... this is simply pushing the system and could lead to complications that simply are not worth it.