The Overhead Join - is it dangerous?

what_next wrote:

Personally, for me the French way of joining circuits is the simplest, here is one of many many similar charts

Don’t let that simple chart fool you. It simply means that the circuit is LH to both runways, and that there is no specific prescribed track like there is at LFPT or LFPN for instance.

According to the French AIP the pilot shall overfly the airfield to ensure that the runway us free of obstacles or crosses, and observe the wind sock.

I find the SOJ the most dangerous and downright idiotic way to enter a traffic pattern. I mean – flying through the departure end at 1000ft? Seriously? If you have to observe what’s going on at the airfield or check the windsock, then there is a much better way to do so, commonly referred as teardrop entry, see picture below. This avoids any conflict with departing traffic and gives you a perfect view of the airfield and, crucially, all quadrants of airspace and potential traffic conflicts.

what_next wrote:

In a typical two-dimensional ICAO style traffic pattern, aircraft which are already in the pattern have the right of way over those joining.

Not necessarily. There was a bigger (unresolved, IIRC) discussion in the PuF-Forum whether the IFR arrival on an established 10 NM final has to give way over someone just turning final from the right, or not. Agreed, if they see each other they will sort it out based on aircraft flown and hassle to give way, but the rule isn’t that clear to me.

what_next wrote:

So I assume that in an OHJ those who descend from the overhead into the “normal” pattern must give way to those already flying there.

In an OHJ you don’t descend into the normal pattern. You join downwind from inside the pattern at pattern altitude. But I agree, on a “normal” airport in a “normal” approach the OHJ is not particularly favourable over a direct join into any other pattern part, be it downwind, direct base or direct final for a straight in. BUT I sometimes stumble across pilots who do find it considerable easier to look out for the airport and only then join the traffic pattern. The OHJ is a procedure that will separate you from most of the traffic, IF:

• The airport has no fast vertical ops (mainly skydivers, winch launches or aerobatics) or those are accounted for.
• The airport has only one traffic pattern (e.g. only to the north)
• The pilot flies the OHJ correctly.

Then, of course, I like the OHJ on non-towered (and/or non-licensed) airfields that you need to investigate prior landing. In fact, it resembles very closely any water landing pattern where you do a (albeit much lower) upwind leg to check the landing area for obstacles, waves and floating traffic. In Germany there aren’t many land airports where this is necessary, though. The one I once flew to was a temporary airfield – or “roughly prepared runway” in eastern Germany that was only established for one weekend.

2greens1red wrote:

mh, would you mind expanding on that?

Not sure what a ‘classic’ overhead join is….surely crossing the upwind end of the runway/strip?

Sure. If you take a look onto the origin of the procedure, you get flying hay-wire crates, round airports and no radios. Pilots back then did need some procedure to get the necessary information for landing: Direction of the wind, possible unusable parts of the airfield, obstacles, other traffic, stuff like that. Now, there was a standard left pattern and so the pilot was placed more on the left of all aircraft, so they flew past the airport on the right, enabling them to see the airport out of their cockpit windows. This is, why even today the OHJ leads you not overhead the airport, but over the threshold or even a bit further upwind. They descended on the “dead side” to pattern altitude and crossed the initial departure somewhere between the opposing threshold and the turn from initial climb into the crosswind leg. This way they could observe the departing traffic, the aerodrome and pattern traffic all the time and stay away from departing and arriving aircraft as they would only cross the pattern where the planes had to be low – around the thresholds. Then they would join downwind and prepare their own landing.

I have heard many explanations of an OHJ that differ substantially from this description, so I wanted to make sure I was referring to the initial idea of the OHJ. I like it as a procedure, that you can use if it is appropriate, and I think it isn’t worse or better than a 45° join or any direct join, always considering the circumstances where the procedure is used.

Airborne_Again wrote:

That kind of join is prohibited by the International Rules of the Air as well as by SERA. All turns in “the vicinity” of the airport have to be done to the left (or right, when there is a right hand circuit) and “the vicinity” includes traffic circuit entries.

Ah not so fast. You are referring to SERA.3225, I guess. Here it is:

SERA.3225 Operation on and in the vicinity of an aerodrome
An aircraft operated on or in the vicinity of an aerodrome shall:
(a) observe other aerodrome traffic for the purpose of avoiding collision;
(b) conform with or avoid the pattern of traffic formed by other aircraft in operation;
(c) except for balloons, make all turns to the left, when approaching for a landing and after taking off, unless otherwise
indicated, or instructed by ATC;
(d) except for balloons, land and take off into the wind unless safety, the runway configuration, or air traffic considerations
determine that a different direction is preferable.

Of course you can join in the downwind (either 45° or 90°). That turn is joining the circuit, not approaching for landing.

mh wrote:

Not necessarily. There was a bigger (unresolved, IIRC) discussion in the PuF-Forum whether the IFR arrival on an established 10 NM final has to give way over someone just turning final from the right, or not. Agreed, if they see each other they will sort it out based on aircraft flown and hassle to give way, but the rule isn’t that clear to me.

In my “book” the IFR traffic has no right of way over normal pattern traffic – at least if weather conditions permit visual patterns. I fly a lot at such airfields and always brief my students or co-pilots about what to do if another aircraft insists on his right-of-way. So far this has not happened yet because usually the radio operator politely ask his circuit traffic to extend their patterns when there is IFR traffic, but he can’t enforce it. The same applies during the first 6 or 7 miles of that 10NM final: One usually is in airscpace E where normal see-and-be-seen rules apply. The fact that I fly along an ILS does not give me right of way with respect to VFR traffic.

Peter wrote:

A lot of people think it is, but the UK mid-air stats don’t support that.

I think it is unsafe.
I was #4 to land at Shorham, all of us were told to call overhead at 2000’. #3 made his call while I still had about 2-3nm to go, so I relaxed and started to prepare the cockpit. Once overhead I made my call just to see #3 at my 10 o’clock passing overhead at no more than 10m away, maybe even less. The other aircraft was at 2000’ or so, I wasn’t as I flew at 1950’, I didn’t like 4 aircraft aiming to arrive at the same point at the same altitude.

mh wrote:

even today the OHJ leads you not overhead the airport, but over the threshold or even a bit further upwind. They descended on the “dead side” to pattern altitude and crossed the initial departure somewhere between the opposing threshold and the turn from initial climb into the crosswind leg. This way they could observe the departing traffic, the aerodrome and pattern traffic all the time and stay away from departing and arriving aircraft as they would only cross the pattern where the planes had to be low – around the thresholds. Then they would join downwind and prepare their own landing.

Its interesting that you describe the dead side track as being “somewhere between the opposing threshold and the turn from initial climb into the crosswind leg”. My understanding was that the ‘standard’ OHJ track was to cross both ends of the runway… which seems reasonable for a slow plane and a long runway. For a 2000 ft runway and 130 kts it generates a roughly 1.5 or 2 G turn. Given that few are going to do that, I’ve never understood how a fast plane is supposed to follow the same OHJ ground track as a slow plane, or how given a broader track how (with a short runway) you eliminate conflict between the fast OHJ plane and the fast climbing upwind leg plane.

To answer the question it’s a UK thing and I don’t regard it as dangerous. It’s there for you to build both a visual and mental map of the traffic in the circuit and tick them off the list as you establish visual contact. The threat of conflict from a Pitts on climb out with crosswind traffic is a fair comment, but is a threat you would manage, as you would when you join downwind in a complex, higher performance aircraft and the circuit is full of training, 80 knot or slower traffic.

There may be an airport where commercial traffic arrives on an IFR approach without ATC somewhere in the UK (possibly an Islander in the Hebrides?), but for commercial arrivals under IFR they will be arriving into an ATC environment and local VFR traffic will follow ATC instructions, usually to make way for the arriving Airbus etc.

Peter wrote:

I don’t know how ATC decide this, but clearly they must, somehow, because a 737 can’t be sent into VFR orbits.

At my base I sometimes ride in a mid-size biz jet flying a straight-in ILS-style approach at whatever (fast) speed that is done. On more than one occasion, the tower has called us as traffic to a C152 mounted student pilot on base leg… It makes me pucker, but the tower is watching the closure rate and usually tells the C152 to “extend your downwind, I’ll call your base” when needed, after the C152 has entered downwind on a 45.

mh wrote:

Ah not so fast. You are referring to SERA.3225, I guess. Here it is:
[…]
Of course you can join in the downwind (either 45° or 90°). That turn is joining the circuit, not approaching for landing.

Well, I guess that is a question of definitions. I would say that you are approaching for landing already when you are entering the traffic circuit.