Learning to fly, or thinking of learning? Post your questions, comments and experiences here

Moderator: AndyR

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By TopCat
FLYER Club Member  FLYER Club Member
#1862230
I agree with @Irv Lee 's comments, but as well as this, the thing that troubles me is simply the enormous size of the manoeuvre. Also, if the drawn line represents the aircraft track, then other than a moment at the SE corner, at no time is the aircraft actually overhead the airfield.

This makes it difficult for aircraft to see each other at a time where it is very important to be able to do so - joining a potentially busy circuit and managing relative spacing.

Here's one of my OHJ's - from this morning as it happens, also from the dead side of the circuit. As you can see, overhead does actually mean 'above the airfield'.

Image

At White Waltham the OHJ height is 1200', with circuits at 800', so the dead side descent would be a little wider than this if the OHJ height was a more standard 1000' above the circuit. But it would still go crosswind over the upwind numbers.
By TopCat
FLYER Club Member  FLYER Club Member
#1862234
johnm wrote:Like most aspects of UK procedures OHJ implies a biplane at 50 KIAS with no radio flying over the airfield to spot the signal square and then lining up to join the circuit, like RPS and QFE it's an RFC anachronism we ought to be getting rid of.

Other opinions are available :)
#1863141
TopCat wrote:
Here's one of my OHJ's - from this morning as it happens, also from the dead side of the circuit. As you can see, overhead does actually mean 'above the airfield'.



A very fine join indeed, though I can hear my instructor saying 'not over the business park'!

Had the active runway been 21 (haha!) - so still approaching from the deadside but with a bit more time/space, would you have descended deadside immediately (G-CD Overhead and descending deadside), or gone all around the roundabout first? (I'm guessing the answer may depend on traffic). My instructors differed on this question.
By TopCat
FLYER Club Member  FLYER Club Member
#1863146
LapsedRinger wrote:
TopCat wrote:
Here's one of my OHJ's - from this morning as it happens, also from the dead side of the circuit. As you can see, overhead does actually mean 'above the airfield'.



A very fine join indeed

Most kind. :oops:

, though I can hear my instructor saying 'not over the business park'!

Why not over the business park? The throttle is pulled quite a way back for the descending turn so unless they were looking up they probably wouldn't even notice.
Had the active runway been 21 (haha!) - so still approaching from the deadside but with a bit more time/space, would you have descended deadside immediately (G-CD Overhead and descending deadside), or gone all around the roundabout first? (I'm guessing the answer may depend on traffic). My instructors differed on this question.

Well 21 is also left hand at White Waltham, so it would look exactly the same, just rotated anticlockwise by 40 degrees.

It's only if you approach from the live side that you can start descending immediately as you cross the upwind numbers to the dead side.

If you descend on the dead side while approaching the airfield, and go crosswind over the upwind numbers, that's not an overhead join any more - it's a crosswind join.

Think of it this way - if you approach on the dead side, you have to get back to the dead side to descend. So you have to turn at OHJ height on the live side to get to it. Then you can descend.
#1863218
Just to clarify, I am also WW based, and having only passed earlier this year, have a lot of recent joins with various instructors on board. One in particular was very fond of saying "don't go all the way round!" But I totally agree that what you describe, and your depicted join, are textbook. I'm afraid I fly a longer downwind leg than you, so if you are ever behind me you are probably cursing!
By TopCat
FLYER Club Member  FLYER Club Member
#1863227
LapsedRinger wrote:Just to clarify, I am also WW based, and having only passed earlier this year, have a lot of recent joins with various instructors on board. One in particular was very fond of saying "don't go all the way round!" But I totally agree that what you describe, and your depicted join, are textbook. I'm afraid I fly a longer downwind leg than you, so if you are ever behind me you are probably cursing!

If there's not much traffic about, then a crosswind join for 21 isn't awful. But it does run the risk of conflicting with traffic descending out of the overhead, which would be higher than the one joining crosswind, and so harder to pick out against the ground clutter. It's very much incumbent on those doing a non-standard join to look out for the ones doing the standard join.

I've learned over the years at WW to space myself out behind the ones flying further downwind than I prefer to. Often I'll slow down to 65 knots or less downwind, which gives them time.

Don't go east of the A404 though, and absolutely don't go so far downwind on 25 or 21 as to leave the ATZ, as that would be an airspace infringement.

If you habitually go quite a long way downwind, especially where base and final are over the built up area, you might like to have a bit of a think about where you'd go, if the engine suddenly went quiet late downwind or on base.
#1863228
So have I underrstood it, thus?
All the while looking out for and avoiding other traffic...
For an OHJ
a) approach the airfield overhead from wherever you're coming
b) while approaching overhead, check for other traffic and
i) if none choose your runway and circuit direction (using whatever information available)
or ii) if traffic further into their circuit, choose the same circuit as them
or iii) if not certain of which option to do orbit (left is conventional) in the overhead whilst assessing your options
then
c) turn in the direction of the circuit towards the deadside for that circuit
d) once deadside, continue your turn whilst descending to a position for a crosswind join
e) fly a crosswind join and circuit.

My questions are:
1. why has nobody ever drawn a diagram for this in the whole history of light aviation?
2. If you already know the runway and circuit direction (eg from the radio) and you know you are joining from deadside, why not just join crosswind?

Prepares to duck
:smurfin:
#1863248
cotterpot wrote:1 - There are several if you search - even one in this thread

2 - Some airfields specify an OHJ

:thumright:


:D
re 1 - touché, but I've not seen a recognised and official one. What about from another direction that's not 90º liveside or deadside, as in approaching, say, from the northeast for an OHJ on runway 27 with a right hand circuit (other circuit options are available).

re 2 - and some specify no OHJ
and some specify no deadside.
#1863250
Entering the term "Overhead join UK" into Google and then on the results page switching to 'Images' will get you a wealth of handy little diagrams.

Mz Hedy wrote: I've not seen a recognised and official one. What about from another direction that's not 90º liveside or deadside, as in approaching, say, from the northeast for an OHJ on runway 27 with a right hand circuit


The Skyway Code V3, published by the CAA is about as 'official' as you can get. CAP1535S to give it its official title. Page 103 might appeal

For other directions simply visualise the circle overhead the aerodrome as a giant roundabout-in-the-sky, join it at any point and continue going round until you pass over the upwind (landing) threshold at which point you start your descent.

Rob P
Last edited by Rob P on Fri Aug 06, 2021 2:00 pm, edited 5 times in total.
By TopCat
FLYER Club Member  FLYER Club Member
#1863254
Mz Hedy wrote:
cotterpot wrote:1 - There are several if you search - even one in this thread

2 - Some airfields specify an OHJ

:thumright:


:D
re 1 - touché, but I've not seen a recognised and official one.

Is the one in the Skyway Code not recognised and official enough for you?

What about from another direction that's not 90º liveside or deadside, as in approaching, say, from the northeast for an OHJ on runway 27 with a right hand circuit (other circuit options are available).

What about it? Perfectly straightforward. Approach from the NE, descend deadside (ie south of the runway), job done.

It is no more complex, and IMO less so (since OH you can see the whole airfield) to orient an approach for an OHJ, than it is to do so for a downwind join, where you don't get a chance to see the field clearly before you're committed to joining in with the rest of the traffic, at circuit height.

re 2 - and some specify no OHJ
and some specify no deadside.

No one is suggesting OHJs at airfields with no deadside, or who don't like them for some other reason.

All this whataboutery - what's the actual point you're making?
#1863284
TopCat wrote:
I've learned over the years at WW to space myself out behind the ones flying further downwind than I prefer to. Often I'll slow down to 65 knots or less downwind, which gives them time.

Don't go east of the A404 though, and absolutely don't go so far downwind on 25 or 21 as to leave the ATZ, as that would be an airspace infringement.

If you habitually go quite a long way downwind, especially where base and final are over the built up area, you might like to have a bit of a think about where you'd go, if the engine suddenly went quiet late downwind or on base.


There is a sort of chalk circle, visible on your diagram, and I turn base abeam that. Crossing the A404 is drilled into us as being 'verboten'. I also tend to make power off approaches on final on 25 and 21 for exactly the reason you indicate. Often also need to chop the power after crossing the railway line on 11, especially if its a sunny day and the field in the undershoot has been ploughed. I was once on a train when one of the Supercubs came so low just as we were passing that a woman in the seat beside me screamed.
By TopCat
FLYER Club Member  FLYER Club Member
#1863290
LapsedRinger wrote:There is a sort of chalk circle, visible on your diagram, and I turn base abeam that.

You'd be hard pushed to make it to the 25 or 21 threshold with a glide approach from there on a windy day. In still air with no flap you might just make it if you cut the corner off but it would be pretty close.

But with a real engine failure, glide performance is quite a bit worse than with the throttle closed and the engine still running.

Personally I don't like going that far downwind if I can possibly avoid it. It's not always possible, but I'd rather slow down than extend.
I was once on a train when one of the Supercubs came so low just as we were passing that a woman in the seat beside me screamed.

Blimey. Yes, you wouldn't want to be doing a glide approach and fly into the side of a train.
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