Frequencies

[gertcoetzee]

I think this has been discussed before, but after some hanger talk I went back to my notes and saw the little sketch I made. Correct me if I am wrong -
In the western cape, under the TMA there is the special rules area, devided into two, east 124.8 and west 125.8 (and this is overlapped by the D200 124.4)
When flying out of the special rules area, eg Vredendal area, if you fly under 1500AGL you are on 124.8, but anything above 1500AGL you have to use the FIR frequency, 126.5.

In the sketch - to the right of the TMA is a little koppie, the dotted line is at 1500ft AGL and it is indicated that the upper limit for 124.8 might be 3500ftASL. Above the dotted line (above 1500AGL) it is 126.5

But wait, there is more. Outside the special rules area (and above 1500AGL) , one is supposed to be adhering to the semicircular rule, and is supposed to talk flight levels. And my understanding is that you would then reset the QNH to 1013 outside the special rules area IF you are above 1500AGL

Annette? Dave? Louis? Please correct and/or explain....

[Tobie]

Yes, you would reset to QNH1013 and refer to flight levels, known as the transision level and the level that you switch to 1013 and back to ASL are different.

Read the book by Dietliff Lemmp, Radio Handbook, she explains not only radio procedures but many other related aviation rules in her book like this one in detail.

My question also, how far north does the special rules area stretch north, some maps show it to about Bokpunt, others like the Jeppeson shows it to stretch right up to the border of Langebaan tma. Thus, does places like Yzerfontein fall under SRA West 125.8 or back to 124.8

[Tobie]

Have time now for a little more info as I understand it.

Altitiude = Distance between sealevel and aircraft.
Height = Distance between ground and aircraft.
Elevation = Distance between sealevel and point on the earth's surface.
QNH = Atmospheric pressure at a point wrt sealevel.
QFE = Atmospheric pressure at a point.
1013hPa = Standard, vertical distance from this setting is referred to as flight levels, FL90 = 9000 ft
Transition level = When descending the FL to change from 1013 to local QNH = at unmanned fields 3000'AGL in VMC (visual metrological conditions)
Transition altitude = When climbing the altitude to change from local QNH to 1013 = min 1000' above the highest point within 25nm from airfield = CPT Int and airfiels within 25nm from CPT INT = 7500ft, further airfields = 2000' AGL
Transition layer = between transition altitude and transition level.

When to use:
QNH expressing position in altitude - within 25nm of an airfield below transition altitude and on cross country flights below 1500' AGL
1013 expressing position as flight levels - above transition level and on cross country flights above 1500' AGL

When to change:
From QNH to 1013 when climbing through transition altitude and when further than 25nm from airfield on cross country above 1500'
From 1013 to local QNH when descending through transition level and 25nm from the airfield on a cross country flight above 1500'

Semi circular rule to be followed from 1500' in uncontrolled airspace.

I think this will apply when further away than 25nm from any airfield, not your departing airfield and does it only refer to registered airfields?

[Tobie]

Gert, I might have sidetracked your topic slightly in the revious reply but still relevant, the question quite applicable to us that will help determine 1013 usage is to know what is regarded as a cross country flight. Is it the distance from your departing airfield like 25nm or is it the distance like 25nm from any airfield or something else perhaps.

[gertcoetzee]

I might have sidetracked your topic slightly

Not at all. Thanks for the explanation.

What I want to confirm is that the frequency when you have changed to the 1013.3 scenario above (flight levels) and thus above 1500t is 126.5 - I got the feeling that everyone sticks to 124.8. What is the correct frequency?

[gertcoetzee]

Posted on AVCOM

Two questionable radio experiences today.

Four trikes (been on correct frequency for 20 minutes, and made all calls) joining the D200 airstrip. As 2nd report right downwind a C210 ask for a wide circuit as C210 is about to take off in opposite direction. Trike 1 abandon on finals, rest of trikes get out of way. C210 is reprimanded by D200 ground radio for not switching radio on sooner (ie then he would have known about traffic). C210 respond that radio was on but headphones not on head. Ground politely tells C210 to put headphones on sooner. C210 takes off, Trikes rejoin and land. Coffee, apologies and no hard feelings.

On way back from the north 4 trikes enter D200 at 3000ft, keep out of parachuting area, descend to 2000ft (now been on frequency for 10 minutes and made position reports) when fixed wing flies headon straight through the formation. Trike1 warns "traffic in D200" with no response. One trike takes evasive action. Trike1 warns C210 doing paradrops that a fixed wing has just passed at 2000 feet, appears to be heading towards the paradrop zone and does not respond on freqency. Paradrop C210 acknowledges and will keep a lookout. After all this a voice comes on air "Student Tomahawk *F* at 2000 feet and changing direction towards Blouberg."

Point. All pilots need to keep a lookout, listen, and talk, when necessary.

[Tower]

Not quite in the same area, but I tried to work it out the other day:

Trip from Microland to Mabilengwe/Vaalwater

1. Take off, Microland 120.35
2, Change to Special Rule East
3. Wonderboom, report inbound, overhead roodeplaat, then outbound.
4. ATC instructs to you call on 124.4

Then What?

PS. Has anybody noticed that Microland frequency is incorrect on most aviation maps. Map says 120.65, we are 120.35

[cobra]

...

Then What?

124.4 Pretoria General Flying Area.

once clear ... VFR traffic 124.80 at or below 1500ft AGL, when above 1500 ft AGL contact JHB N Info (FIS) on 127.4

Kitty Hawk - 120.65

[Tobie]

Gert,

With reference to FIR Cape Town Central:

Broadcast 126.5 - ( flight information service frequency for Cape Town Central from 1500' AGL to FL105 ) - these frequencies are to be used in uncontrolled airspace, outside Special Rules Areas and above 1500' AGL.

The Cape Town Central sector are divided in two layers:
1) FL110 and above (Cape Town Central) - 125.1 - provide area control service for aircraft in controlled airspace and information service to aircraft in uncontrolled airspace between 1500'AGL and FL110
2) 1500'AGL to FL105 (Cape Town Information) - 126.5 - no flight information provided, pilots broadcast only.

In uncontrolled airspace at and below 1500' AGL and outside the limits of the Cape Town Special rules area, TIBA ( traffic information broadcast by aircraft ) - 124.8
In all General Flying Areas the TIBA frequency is 124.4

I'm not sure what the lateral limits of the Cape Town Special Rules Areas are, be it 25nm radius from Cape Town Int or are they defined limits indicated on the aeronautical maps falling perhaps on the same boundaries as the CT outer TMA

So Gert I agree we sometimes fly broadcasting on 124.8 instead of 126.5

[Tobie]

Special Rules Area Cape Town = all areas below CPT TMA exl. FAD's FAR's FAP's ect.

[Biggles]

Hmm, had an experience today in the area Gert is talking about and had to come here to check i was on the right frequency.

Flying low-level from Ysterfontein to bok-punt broadcasting TIBA on 124.8, radio functioning fine. I had heard no transmitions except from aircraft over franschhoek, when out of the sea spray comes a trike only marginally higher than me... I did not hear any transmitions subsequent to this either.

So under in un-controlled airspace under Langebaan weg airspace was I on the correct frequency(124.?

[gertcoetzee]

Yes, under Langebaan Controlled space the frequency is 124.8 BUT notice that unlike anywhere else the Langebaan space is FAR45"A" FL195/1500AGL

But in practice, at sea, at that spot s/he should have been on same frequency.

The northern sector of Langebaan space, FAD46 has an additional restriction 1500GND/GND but if you speak to control they tell you to transmit 124.8 there.

When I fly there, in week, I phone them before - very accommodation andfriendly.

[Tobie]

Biggles, he might have been on 125.8, I think some pilots are under the impression that the CT SRA stretches further north than Bokpunt, (edge of CPT TMA ) as I mentioned previously the Jeppeson map physically show the line stretching up to the Langebaan area so to speak, leaving you to believe that places like Yzerfontein is still on 125.8 and not 124.8

[RV4ker (RIP)]

A bit late on the this one, but the problem that exists is that many guys (especially in the outlying areas) broadcast on 124.8 REGARDLESS of their height, which is why controllers always say NO REPORTED TRAFFIC AT FLXXX. I often find jockeys (in expensive aeries) bulleting along merrily at Fl075, Fl085 and higher broadcasting as 7500/8500 feet on 124.8. If radar coverage is good, ATC will alert you to their position, but don't think a trike is going to have a return and none i know of have transponders.

In theory Gert you are right. When you switch to FIS (Flight Info Sector) you are on 1013,2 and report your height as flight level on 1013,2. Semi circular rules apply and controllers are there to advise you of any conflicting traffic, but you are not under their control and separation is up to you (eyeball 101). Effectively if you are routing low level (<1500 AGL) you would broadcast 124.8. If you are going higher up then you would contact/broadcast on FIS freq. I would assume it possible to e on FIS at FL015?

I tend to make broadcasts on 124.8 while on the FIS freq at regular intervals after a couple , just to make sure there are no silent bandits in the area as there is no radar coverage below FL145 and thus the controllers can only alert me to traffic they are in contact with.

The C210 should have fitted in with your pattern. I will usually accomodate a request to delay to allow a guy to get going, but often some jerks will do their runups on the runway numbers (as they did not hear any other raffic )

The Students arelearning and I am amaised how many do not know when someone is actually talking to them or is the "conflicting traffic" they always calling for. It ofte seems they are making radio calls only because they have to and have no mental picture of the surrounding airspace. on the other hand we have very busy airspace below the TMA in Jhb and some broadcast their position every 2 mins and personally confirm that every caller is not "confliting traffic". Solution is a happy medium, but I digress.

[Learjet]

Eish! I always switch to 125.8 when exiting to the West of the D200 (124.4) towards the coast and up to Yzerfontein. I am (was? ) under the impression that the coastal strip still falls within FACT SR West ??? Sure looks that way to me on Easyplan and my chart?