Peter wrote:
This US AOPA article depicts what must be a common situation.
It is a possible situation that pilots who fly regularly into uncontrolled fields should understand, but it is not common when conditions are low. Most VFR traffic does not fly in these conditions. I personally would prefer if all non towered airports with instrument approaches were class E to the surface, but that is not the case as most are class G from 700 AGL to the surface. The FAA is highly unlikely to change the classification of G to E as it would probably be resisted by AOPA.
Silvaire wrote:
Pattern altitude is typically 1000 agl at US uncontrolled airports, sometimes 800 ft.
There is AIM guidance but not a regulatory requirement to use the pattern altitude. Often circling altitudes are well below pattern altitude. If conditions permit, circling at pattern altitude is preferred.
In the USA, it is a beautiful VFR day in the pattern at an airport with an instrument approach and Class G surface to 700 AGL anytime an aircraft is clear of clouds and has a 1 SM visibility. So 200 overcast and 1 mile qualifies. As long as the VFR airplane remains clear of clouds and does not overfly a congested area, there is no requirement that the pattern be flown at pattern altitude. If the airlines were to fly into an airport without a tower, they would request that the airport be class E to the surface, which would legally ground VFR flying until 3 SM visibility and mandate that if conditions were VMC, VFR traffic would need to remain at least 500 feet below the ceiling and 2000 feet laterally from any cloud.
As others have stated, one is cleared for the approach prior to the FAF and instructed to switch to the local traffic pattern frequency. Pilots are also instructed to cancel or close their IFR flightplan via radio (usually on the ATC frequency or via the RCO if one exists) or via phone, as ATC will not free up the airspace for IFR departures or approaches until this occurs. It is one IFR aircraft in or out at a time. The approach clearance includes keeping the aircraft operating under IFR until closed or back in contact with ATC on the missed approach.If the flightplan is not closed, a SAR will be initiated.
Pattern altitude is typically 1000 agl at US uncontrolled airports, sometimes 800 ft.
HighFly wrote:
…essentially all uncontrolled airports with instrument approaches in the US are designed to be protected by Class E airspace, either to the ground (in that case the Cub wouldn’t be flying in the circuit in weather below VFR minimums anyway) or down to 700 ft AGL – in which case that Cub would also need to meet Class E VFR weather minimums while in the circuit, which means at least 500 feet below the base of the cloud layer PLUS 3 miles visibility. If the Cub were flying in the pattern at 800 ft AGL, then the lowest minimum for the cloud base while still being legal would be 1300’ AGL. That’s plenty of time for see and avoid for the approaching IFR traffic.The cloud distance requirements don’t extend to neighbouring airspace. If it’s class E down to 700 AGL, then it is class G below that, correct? So there could be a cloudbase of 700 ft with the Cub flying a circuit clear of clouds at 699 ft with 1 SM visibility. Smart? No. Legal? Yes.
The system has a built-in safety function already : Class E airspace. It works wonderfully.
First off, in the US, a radio is not required equipment for VFR flight. So a Cub could be in the pattern in crap weather flying circuits without a radio, as long as they are clear of clouds and have 1 mile visibility (below 1200 ft AGL) – in class G airspace…but there wouldn’t be an instrument approach to such an airport, because…
…essentially all uncontrolled airports with instrument approaches in the US are designed to be protected by Class E airspace, either to the ground (in that case the Cub wouldn’t be flying in the circuit in weather below VFR minimums anyway) or down to 700 ft AGL – in which case that Cub would also need to meet Class E VFR weather minimums while in the circuit, which means at least 500 feet below the base of the cloud layer PLUS 3 miles visibility. If the Cub were flying in the pattern at 800 ft AGL, then the lowest minimum for the cloud base while still being legal would be 1300’ AGL. That’s plenty of time for see and avoid for the approaching IFR traffic.
So it works beautifully. There is a buffer of 500’ vertically should instrument traffic pop out of the clouds and encounter a no radio traffic – safety backstop #1 “see and avoid” and failing that there is safety backstop #2, the CTAF frequency, should said VFR traffic have a radio (and be using it).
It’s a grayish fall day with a 900-foot ceiling and two miles visibility as a turboprop breaks out of the clouds on an instrument approach to a nontowered airport. The runway is in sight—and there’s a Piper J–3 Cub taxiing on it.
And how is this different than flying VFR at 7-800 ft and suddenly seeing a J-3 or an elephant, a diesel truck or whatever on the runway ? I presume this is in G? Seriously, on an untowered airport, you don’t know what is on the runway. It’s an unknown variable. That is why, there is a tower on AFIS units, and it’s the main duty of the person in there to report the condition of the runway, if it’s “free” or not, to both VFR and IFR. Two way communication is a must of course, but the article say nothing about that or airspace.
Doesn’t SERA say something about this? It’s always the pilot’s duty on an untowered airport to make sure the runway is in a shape that makes it possible to land.
Silvaire wrote:
Meaning that the aircraft on an instrument approach will be looking out the windows
Looks like restating an obvious thing that we usually forget, at 50ft from touchdown, looking out of the window is advisable even if that Cub was operating IFR in IMC on CATII conditions 
I am probably wrong, but think as PIC you have a requirement to “look outside the window/do avoidance” irrespective of the ATC service you receive or the conditions of your flight (say, you fly IFR in class D airspace in VMC/IMC, atc will take care of keeping their complex separation criteria as practical as they can, or get a black mark/suspension, but as PIC you are still liable to look outside and take the necessary avoidance actions?)
I don’t see the issue, if the Cub or whatever is flying VFR it’s in VMC… Meaning that the aircraft on an instrument approach will be looking out the windows just as he would on any other final approach. If there’s a non-radio Cub on the runway, the approaching aircraft goes around. That’s how instrument approaches into uncontrolled airports work, and accordingly how the minimums are defined. If the ceiling is 900 feet, as in the article, obviously there is no issue.
One time I was flying a safety pilot for a friend, doing instrument approaches at an uncontrolled field. I watched carefully until he pulled the hood off to land, and then pointed out that there were half a dozen parachutists directly in front of him. I will admit to giving him some warning prior to that, and in low ceiling conditions with no hood obviously they would not have been there.
In practical terms, this might be inconvenient for the approaching aircraft but there is no hazard and it happens so infrequently in real IFR that it’s a non issue even on the basis of creating an inconvenience. In places where non-radio Cubs fly, there are very few aircraft making instrument approaches in IMC. In places where aircraft make instrument approaches and Cubs fly, the Cubs will almost always have a handheld… Which BTW requires no approval, license or other claptrap in the US.
In fact, and that‘s what the article is about, it‘s just the way flying at uncontrolled airfields works and the TBM pilot didn‘t know. It‘s in the word: uncontrolled. Hence, nobody decides for the pilot which runway to use and also, no obligation to use a radio.
