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91.215 "deviations"

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minitour

Well-known member
Joined
Apr 17, 2004
Posts
3,249
Pretty good "discussion" today in ground school about this one.

Okay, so we all know that you can't operate in Class C airspace without Mode-C. But according to 91.215 if we get an ATC authorization, we can.

91.215
(d) ATC authorized deviations. Requests for ATC authorized deviations must be made to the ATC facility having jurisdiction over the concerned airspace within the time periods specified as follows: (1) For operation of an aircraft with an operating transponder but without operating automatic pressure altitude reporting equipment having a Mode C capability, the request may be made at any time.


So let's assume we're out on a flight and our Mode-C isn't showing up with anyone, well we decide we're done so we turn around to head home (Class C Satellite Airport) and contact approach with a request for a T&G at the primary airport, if approach says "roger expect runway 32", does that count as the "authorized deviation?"


The class is split about 50-50. It came up because I guess a controller jumped all over an instructor the other day when he was handed off from approach to local for the touch and go (this exact scenario). The student says his instructor said he talked to approach and they didn't seem to think it was a big deal, but if it was they would leave. To which they were cleared for touch and go.


I'm with the half that thinks this counts as the "authorized deviation" since the controller could have said "negative, remain clear of the class C airspace" or something like that...


opinions? legal references? time for the CFI to fill out a NASA? It was a commercial student (already a PPL) so if the CFI needs to fill one out (as PIC) would the student also (as PIC?)


-mini
 
That scenario does not paint the picture of an authorized deviation, in my opinion. Nothing has been stated to approach that the Mode C in your transponder is not working. It is the instructor's responsibility to inform ATC of any equipment failure, mandatory in an IFR enviornment. It is laxidazical at best for the "professional" instructor to assume he is good to go because ATC gives a clearance with only half the required information.

The heart of the reg is that ATC have some advanced notice. These guys never made any "Request for authorized deviations" they just called to get a clearance.

If anyone is going to fill out a NASA form in this case, it would be the CFI only. The CFI is acting as PIC, while the commercial student is logging PIC

Just my .02
 
Looking at the language of the regulations, I doubt that "establish [and maintain] two-way radio communications" [91.130(c)] equals a "request" for an ATC authorized deviation [91.215(d)].

To say that there was an authorized deviation here, you would have to say =both= (1) that flying without an operating transponder is an "automatic request" =and= (2) that ATC saying nothing about the transponder is an "automatic authorization". I don't see anything that suggests that either is correct, let alone both. If anything, the hoops in the rest of 91.215(d) indicate just the opposite - nothing about this is automatic.

I dodn't see any harm in both pilots filing a NASA report. Remember that while the PIC is the one who is ultimately responsible for a flight, the PIC is not the =only= one responsible for a flight.
 
Mode-c is one of those things you can't preflight, and if it stops working in flight you don't inform atc... they inform you. Then you don't know if it's really broke good or intermitent, or maybe just a little hiccup.

The good new to your scenario is that mode-c is not required to fly underneath class-c, if that's where the home base airport is then no problem. The touch and go at the primary airport would not be a great idea since the lesson was apparently called off because "Mode-C isn't showing up with anyone, well we decide we're done". Well touch and goes at a different airport aint done. That's like saying "hmmm looks like our radio isn't working, let's go out of our way now to enter some class B and do some touch and goes at the primary with light gun signals"... well ok its not that bad.

Anyhow the point is mode-c can stop working anywhere and at any time. It was not a known problem prior to the flight. Finding out about it in flight and then entering class-c where you don't need to be probably isn't the smartest thing to do.. but hey its probably not the dumbest either.

Of course if the mode-c was discovered to be inop while in class-c then you can hardly blame the pilot.
 
Oh yeah, now that I have said all that... I don't think the ATC communication qualifies as a deviation... but I am not real sure either.
 
Cool...I see what y'all'r saying about the "request".

Now lets play another game:

Say approach told you "hey your mode C isn't working" when you were inbound to the primary airport and you respond that you'd like to request a touch and go or even a full stop cuz you need to pick someone up.

Does that constitute the request since they knew your mode c wasn't working?

I'm just concerned with the language...I don't want to be stuck on a checkride in one of these planes and have the mode c go inop and not know the correct language.

Do I need to bust out a "our mode c isn't working we'd like to request through the class charlie airspace enroute to ___" ? or is "hey our mode c isn't showing up, is direct to ___ a problem?" okay?

Just a little concerned with the CSEL/MEL and CFI checkrides right around the corner...I'd hate to pink and have to fill out a NASA at the same time on the same flight.

-mini
 
minitour said:
Do I need to bust out a "our mode c isn't working we'd like to request through the class charlie airspace enroute to ___" ? or is "hey our mode c isn't showing up, is direct to ___ a problem?" okay?
Pretty much. Unfortunately, I haven't seen any AIM-standard phraseology on this one. If you are contacting the facility and already know that your Mode C is inop, a simple

"Approach, Skyhawk 1234X. Negative MODE C. (or MODE C INOP) Request deviation to transit Class Charlie enroute to Podunk"

should do it.

If ATC is the one to inform you,

"Request deviation to transit Class Charlie negative MODE C enroute to Podunk"

is enough.
 
It would certainly be prudent to inform ATC of the inop Mode C on first contact. Best to be up front than to have a misunderstanding or worse down the road. It only takes a few seconds to let them know about the Mode C, so why not just mention it and be safe? I find that in situations like that, ATC is glad to have the info and appreciates you being up front about it.
 
The most salient point of this thread, as yet not discussed, is not weather establishing contact constitutes an authorization to proceed with inoperative equipment (it does not), but rather failure to adhere to 14 CFR 91.125(a).

Apparently a crew of two pilots, a student and an instructor (?) proceeded based on an assumption regarding the intent or authorization afforded in an ATC clearance.

When a pilot is uncertain of an ATC clearance, that pilot shall immediately request clarification from ATC. If you're not sure if you've received authorization to operate without the transponder, then ASK!!!. Don't make an assumption. Ask. It's good practice, and a violation of regulation when you fail to do so.
 
avbug:
I don't think that really applies here.

I do understand what you're saying, and that's what I'll be doing unless they specifically tell me "proceed as requested" or "bla bla without mode c bla bla" (should the situation, hopefully, not come to me).

But they were sure of themselves when the controller said to expect whatever runway that the deviation was okay.

It only came up when we were discussing required equipment and radio stuff in certain airspaces in ground school when the student said "oh yeah well if you get authorization...".

Actually the ground school instructor started going off about not going through certain airspace without the mode c working and how you shouldn't even fly a plane that has a mode c transponder if the mode c isn't working. I thought the vein in his head was going to explode. He was pretty adamant...of course he's also the guy that told us flying over gross is "okay" as long as you aren't out of the CG envelope. Which I don't understand, because the CG envelope in all of my POHs stops at MTOW...but that's another thread...

I do think that's a great point though, to ask...and I made a mental note in case (like I said) that ever happens to me, I won't have to fill out the NASA, because I'll know.

...anyway...

...anyone have anything firm to go on regarding the correct phrasing they want to hear for the request? Is this a call the FSDO and ask them thing or is that just going to open up an unnecessary can of worms?

Thanks again for the discussion

-mini
 
An authorization to proceed, sans any request for a deviation from transponder or altitude reporting capabilities, does NOT constitute an authorization to deviate from those requirements.

A controller cannot authorize an aircraft to operate without mode C or without a transponder unless the controller has been made aware of the nature of the equipment deficiency, and unless the request for a deviation has been made.

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.
 
right...and we've established that to be the general opinion of the members of the board...if they don't know, they can't authorize it...

...that doesn't necessarily validate 91.123(a) though...for that to work, the pilots would have to be un sure of the clearance...in their minds they were sure...wrong? yes...but still in their minds they were sure

however...

in scenario two, approach tells you that your mode c isn't showing up...so obviously they know because they told you...so you "request" a full stop, "Cessna 123 request full stop runway 14R". If they tell you, "roger, expect left base 14R" is that considered a deviation or do you have to: "request full stop 14R negative mode-c"?

I'm more concerned with the language that needs to be on the tape. With some of the school's airplanes, I never know from one day to the next whether I'm going to have mode-c, no flap landings, lost communications or what-not...so I want to be ready for anything.

so...what's the deal on the language? Come on...there's got to be someone out there in ATC land or FAA land that knows...I've been searching databases for the past few days on all sorts of stuff but haven't found anything leading me to believe there is an "official" opinion on the matter...

-mini
 
Mini,


I can't provide you with a link to written guidance on any of the above. The .65 speaks to inflight deviation requests for no Mode-C above 10k, but not specifically about flight in Class C airspace.

However, in the places I've worked, we don't normally get too worked up over it, so long as the owner/operator gets it fixed in a reasonable amount of time. If we tell you it's broke, and 3 weeks later, it's still broke, and you've been flying regularly all that time, expect a chat with the Supe. If it just failed that flight, or that morning, then we're not Mode-C Nazis. "Alright if we come on in anyway?" is probably as good as "Request to deviate from Mode-C requirements" or some such....:rolleyes:
We're a bit more uptight if the transponder isn't working at all. You can still get permission, but we'll usually want to discuss things on the phone first.
 
Vector4fun said:
...If it just failed that flight, or that morning, then we're not Mode-C Nazis. "Alright if we come on in anyway?" is probably as good as "Request to deviate from Mode-C requirements" or some such....:rolleyes:
We're a bit more uptight if the transponder isn't working at all. You can still get permission, but we'll usually want to discuss things on the phone first.
Nice to hear from the ATC side of the story. Seems like that was the way the conversation went with their approach guy. (at least their side of the story)

Thanks again for the discussion everyone...I still can't find anything "official" on the topic...

Would calling the FSDO be asking for trouble?

-mini
 
The FSDO isn't authorized to provide you any such insight, and anything you get from the FSDO has no more value than opinion. Very often, a wrong opinion.
 
okay...so who has the authority to make a decision on what "officially counts" as a request for a deviation?

-mini
 
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.
 
avbug said:
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.
 
Last edited:
minitour said:
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.
 
midlifeflyer said:
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
 

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