Question about Class C airspace

[djrisc]

Hi,
I have a noob question about Class C airspace.

What is the norm for VFR traffic traveling across Class C airspace (ie. they don't -need- to go in to it.) do most real pilots just fly over it and avoid it all together, or do they request and just go straight through it?

I'm just curious what's considered "normal" behavior for traffic just "passing through".

Thanks!

Brett

[Keith Smith]

Plan your flight as though it doesn't exist. Then, if your ideal profile has you going through it, then plan on going through it. It really will be a non-event in most cases.

Here's a video showing a transition through Class C enroute to an airport not within the Class C airspace: https://www.youtube.com/watch?v=LFaftfkMyUU (forward to the 1:55 mark)

[djrisc]

Thanks Keith!

Brett

[Keith Smith]

Brett, that was a great question, btw. It's one thing to know the official rules about how to do certain things...it's another to know what's considered good or bad form in the real world.

By example, ATC cannot assign a speed restriction within a 5nm final, or inside the final approach fix. One might be lead to believe that you can do anything you want, then, once you're inside that area. Practical experience, though, will show that it's good form to adjust speed as necessary as the situation calls for, whether it's making life better for you, the aircraft ahead of you, or the line of aircraft behind you.

[Mark Hargrove]

By example, ATC cannot assign a speed restriction within a 5nm final, or inside the final approach fix. One might be lead to believe that you can do anything you want, then, once you're inside that area. Practical experience, though, will show that it's good form to adjust speed as necessary as the situation calls for, whether it's making life better for you, the aircraft ahead of you, or the line of aircraft behind you.

This doesn't mean that the "200 kts or less within the vicintiy of an airport" restriction is removed though, does it? Not that I can understand why somebody would fly an approach inside the FAF at >200 kts unless you're flying the space shuttle -- I just want to make sure I know the rules.

-M.

[Keith Smith]

Mark, the 200kt rule is not an ATC restriction, it's mandated by the FARs.

[Mark Hargrove]

After reading the applicable FAR, I understand this whole deal a lot better now. The FAR is pretty short:

Sec. 91.117 — Aircraft speed.

• (a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).
  
  (b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a) of this section.
  
  (c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph).
  
  (d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.

-- and now I understand why planes are allowed to fly at >200 knots during arrivals and approaches into airports like LAX. That's always bothered me a little bit because I'd just verbally head the 250 knot below 10,000 and 200 knot "in the vicinity" rules without having read the FAR. Now I know what "in the vicinity" actually means. It's closer to the airport than I thought.

[Orest Skrypuch]

Class B is a little different (91.131), unlike the Charlie & Deltas there is no speed limit within a Class B, except the general restriction of less than 250knts below 10k.

Also, on takeoff, once above noise abatement, 747s and heavy 777s routinely fly at greater than 250 knts (even below 10k), as their minimum clean speed is greater than 250 knts.

* Orest

[Orest Skrypuch]

Also, one other tid-bit, when flying internationally ...

Many countries (by ICAO), once clear of noise on takeoff, allow fast aircraft to accelerate to their normal climb speed (even if that is greater than 250knts), even if below 10k, as long as their planned cruise altitude is greater than 10k, which would be virtually always true. Canada is included in that group.

* Orest