UNICOM - Worse than useless?

[facthunter]

Seperation.

 

Browng, you've lost me there. On final they are presumably tracking on the extended Rwy centreline, at varying gradients and speeds. Surely this is the area where the difficulty arises. Allowing for the possibility of a straight-in approach happening as well. The only time to vary the circuit (Adjust your touch-down time) realistically, is by extending down wind, and by then you should know where ALL the aircraft ahead of you are , and to know in your mind, the landing sequence. If you find that the seperation is less than you anticipated, evasive action is needed. Do you think enough attention to this factor is paid during training? I don't. Nev..

 

 

[Guest browng]

Browng, you've lost me there. On final they are presumably tracking on the extended Rwy centreline, at varying gradients and speeds. Surely this is the area where the difficulty arises.

Indeed, and in our case the "varying gradients and speeds" are extreme, the descent gradient of a Gyro doing a practice auto rotation has to be seen to be believed! This is unavoidable where widely varying types are operating together. It is a matter of training and discipline, as are most things that really matter in aviation.

 

From our Ops Manual; (transcribedf rom the CASA VFR Ops manual)

 

"2.4.4 Altitude on down-wind should be either 500ft AGL(rotary wing and fixed wing <55Kts), 1000ft AGL (standard fixed wing, 55-120Kts) or 1500ft AGL (high performance fixed wing > 120Kts)."

 

 

 

The above prevents a fast type running down a slow one on crosswind and downwind, the higher aircraft can see the lower if its in front, and if the lower aircraft is behind the higher one and not visible, there is no threat as the upper aircraft is faster and will only increase the separation.

 

Allowing for the possibility of a straight-in approach happening as well. The only time to vary the circuit (Adjust your touch-down time) realistically, is by extending down wind, and by then you should know where ALL the aircraft ahead of you are , and to know in your mind, the landing sequence. If you find that the seperation is less than you anticipated, evasive action is needed. Do you think enough attention to this factor is paid during training? I don't. Nev..

I agree, and in the case of our 'stacked' circuits, the procedure from the base turn is perfectly normal. I do not think that enough attention is paid to this factor in training, and personally I think that it is a mistake to teach the kind of 'square' circuits that we do anyway. I prefer curved approaches, they give a more stable and linear approach all the way from the base turn to touchdown. The RAAF uses curved approaches, (see below), but they do take a higher level of skill to properly execute, and are I believe another area where training standards have been gradually eroded.

 

http://www.2wgaafcsoa.com/powered_data/TrainingData/PA38_Standard_Circuit.pdf

 

 

[facthunter]

Approaches.

 

Browng, I would have done more curved approaches, than any other. They are better in faster aircraft, and feel smoother, but I believe they are harder to execute properly. They are also harder to judge from the right hand seat, as you are always looking at the touch-down point, across the cockpit, untill you are aligned on final . The thing that I felt lacked emphasis, (if it's ever addressed at all in training) was appropriate EVASIVE action, should the need arise. We say do a go-round, but there's sometimes a few aircraft in the way. Nev...

 

 

[Guest browng]

The thing that I felt lacked emphasis, (if it's ever addressed at all in training) was appropriate EVASIVE action, should the need arise. We say do a go-round, but there's sometimes a few aircraft in the way. Nev...

I'm a bit out of touch on the training regime, do you mean a go-around is taught for that eventuality or a live-side orbit? Lets say I'm number three, and number one ground-loops on touchdown blocking the runway, number two does a go around, what do I do? I was taught to continue the approach, overtaking the aircraft ahead if required, tracking a line beside the runway on the live side, maintain level flight along the runway and then re-join climbing crosswind. Any other offers?

 

EDIT - I'll elaborate on "overtaking the aircraft ahead if required". Note required, e.g I'm a Bonanza and he's a Thruster and I just can't fly that slow.

 

 

[facthunter]

Evasive action.

 

Not from me at the moment. I'd like to see a few views on this. I'm going to be a listener for a while. Nev..

 

 

[Yenn]

As I see it the only way for a slow plane on final to be obvious to a faster plane is to be above him. that means steeper approaches, wnich in my opinion are appropriate for RAAus aircraft. I can fly the circuit at the same speed as a C180, but much prefer to be way above the 3 deg approach favoured by a lot of GA pilots.

 

It doesn't matter much what height the circuits are at some point we all come together on short final, and any way of being visible to the faster traffic is a bonus.

 

I don't have the facts for the Latrobe Valley accident, but given the visibility from a C172 I would have to believe the ultralight must have been very low on his approach, or the C172 was dragging it in with a high nose and low speed.

 

 

[slartibartfast]

Nev and Browng - regarding your evasive action scenario :- I'd prefer to overtake if necessary on the right. Overtaking on the live side for a left hand circuit would mean overtaking on the left and that's like the Spanish Inquisition (nobody expects it). I would then continue straight and climb to 700' before turning crosswind and rejoining downwind with new sequencing. If there was any doubt about the new sequencing and the runway clearing, I'd continue straight and leave the circuit area until it got sorted. I don't remember this scenario coming up in training, so correct me if I'm dangerous.

 

 

[Guest browng]

Nev and Browng - regarding your evasive action scenario :- I'd prefer to overtake if necessary on the right. Overtaking on the live side for a left hand circuit would mean overtaking on the left and that's like the Spanish Inquisition (nobody expects it). I would then continue straight and climb to 700' before turning crosswind and rejoining downwind with new sequencing. If there was any doubt about the new sequencing and the runway clearing, I'd continue straight and leave the circuit area until it got sorted. I don't remember this scenario coming up in training, so correct me if I'm dangerous.

The reason you orbit on the live side is that if you have parallel runways with opposing circuits (e.g Jandakot, the busiest airfield in Australia), there is no dead side, otherwise it could be messy. Remember this is an emergency procedure and therefore must be simple and consistent.

 

 

[slartibartfast]

The reason you orbit on the live side is that if you have parallel runways with opposing circuits (e.g Jandakot, the busiest airfield in Australia), there is no dead side, otherwise it could be messy.

Fair enough. I can't think of an airfield I would be allowed into with parallel runways, but if that ever came up I'll remember to pass on the live side. Thanks.

 

 

[Guest browng]

Fair enough. I can't think of an airfield I would be allowed into with parallel runways, but if that ever came up I'll remember to pass on the live side. Thanks.

In fact you don't actually need parallel runways for this to be an issue, just opposing circuits, e.g. single runways where powered aircraft do circuits in one direction, and gliders in the other. These procedures have been developed over many decades, 'improving' on them tends to result in smoking holes.

 

 

[Guest Andys@coffs]

Once again Ive learned something. I too, like slarti would have mossy'd over to the dead side, after all I was taught to overfly (above cct height) descend on the deadside, aiming to join in a descending crosswind. Nothing was ever spoken regarding parralel operations... and my field is a gliding field with some dead side activity, but mostly the gliders comply with std (powered) cct convention. Of cours in the scenario we are operating at or delow cct height. Dead side I discussed above was above cct height.

 

Andy

 

 

[rong]

From the Flying Training Manual (Aviation Theory Centre): " The dead-side, away from the circuit direction, is preferred". A lot of pilots have been taught from this.

 

But it also says "However, stay on the centreline if there are parallel runways" which, as said above, doesn't apply to GAAP: "position the aircraft on the active side and parallel to the nominated runway, while maintaining separation from other aircraft ..." (Visual Flight Rules Guide, CASA 2007).

 

Ron

 

 

[Guest pelorus32]

Just thinking about a Tecnam in a 1000' circuit and a B200 in a 1500' circuit.

 

Still air the Tecnam is traveling at 1 mile a minute on final, the B200 (help me Howard Hughes) is travelling at something close to 2 miles a minute - let's say slightly less at 100 knots.

 

From the base turn the Tecnam has 1000' to lose and about 2 miles to run so it needs a descent rate of around 500 feet per minute - and that's about what you do.

 

But that makes a glideslope of around 4.5 to 5 degrees.

 

The B200 has 1500 feet to lose and for a 3 degree glideslope that he/she would be looking for at say 100 knots then the ROD will be 500 fpm, requiring 3 minutes to touchdown. This requires 3 minutes from base turn to touchdown or 1/20 of an hour giving you 5 miles from base turn to touchdown.

 

That means that his/her base and final are about double the length of the Tecnam and most of the way he/she is coming down on top of the Tecnam.

 

Someone may care to work out where their final glideslopes cross.

 

Is this any safer?

 

Regards

 

Mike

 

 

[Guest browng]

Is this any safer?

Regards

 

Mike

A perfectly good question, but as somebody has already said, aviation carries risks, and we cannot eliminate them all. The key is knowing what to expect, what everybody else is doing. If we all apply the same procedures, however imperfect, that consistency alone is a risk minimalisation strategy, note, minimalization not elimenation. As we have seen from the confusion over the correct procedure for an orbit, we are not all taught the same thing. I'm not saying what I was taught is the only way, but I do find it worrying that it seems training fails take into account a simple opposing circuit, something that is not at all rare or exotic. It does emphasize the importance of proper flight planning, of obtaining full information about your intended destination, the fact that opposing circuits operate should not be something you only learn on arrival.

 

 

[facthunter]

More views.

 

I'm still listening, but this is good stuff.. Nev..

 

 

[Matt]

Interestingly there's no CASA or Airservices procedure for "Go Around" at non-controlled aerodromes. The only procedure which exists (that I can find) is AIP ENR 14 (http://www.airservices.gov.au/publications/current/aip/enr/1_1_1-116.pdf) which is reproduced in the CASA Visual Flight Guide. There's no reference to non-towered aerodromes at all...hence the variations in that being taught to students.

 

My training was to fly parallel on the dead side, climb and join crosswind - this was normally mid-field or thereabouts. Training did include the procedures in AIP to controlled and GAAP aerodromes.

 

 

[Kaz]

Going back to the opening post here...

 

There is an alternate view however that UNICOM is simply worse than useless. This view holds that if you are going to lull people into a sense of security by telling them that there is a UNICOM then there had better be a UNICOM that does what it says it does.

Unicom services will provide general weather reports, basic air traffic information and details about the services and facilities available. They will not be your eyes or your conscious, you are still the pilot and your are still responsible. Even when flying in controlled airspace do you just sit back and wait for someone to tell you what to do? Should ANYONE at ANYTIME be lulled into a false sense of security when flying? And if you do, should you sit down and have a bit of a think about that??

 

NA on that basis elects for a straight in approach, there's no other traffic, the wind's straight down the strip and who wants to be dicing with galahs in the circuit?

Late on final NA flies into the top of WF and they are both killed.

Would any of you in this situation just assume there is no traffic and not bother scanning for other aircraft? Would you not bother with radio calls because you think no one else is in the circuit anyway? Mistakes happen, maybe the other guy had a radio failure. Maybe he doesn't have a radio (although that is a separate issue I won't get started on!;))

 

So my question here is - If you are a good pilot and you do the right thing, then why would a Unicom be a bad thing?

 

I also think people need to question themselves on whether they can do more training, be a more effective pilot, read more articles and enhance their knowledge. Yes, flying is a sport and should be enjoyed, but it is a high risk sport and you never stop learning.

 

Thanks for listening ;). As a non-pilot I have a lot of time when we're flying around to think of all these things (in between serving meals and changing the tunes:laugh:). I don't understand why a person would go through all the training and expense to become just a mediocre pilot.

 

**Note - Unicoms trials are starting in Wagga and Dubbo in the next 2 weeks**

 

 

[Guest browng]

Interestingly there's no CASA or Airservices procedure for "Go Around" at non-controlled aerodromes.

Is there a clear definition of a 'Go Around' that differentiates it from an 'Orbit'?

 

In my day the two were distinctly different, i.e. a 'go around' or 'baulked approach' was carried out along the runway centerline, an 'Orbit' as previously stated, was to the live side. In my earlier example, with No1 blocking the runway, if No's 2 and 3 both did a 'Go Around' as defined above, there would be a real chance of a collision in the vertical, particularly if they have different rates and/or angles of climb, by No3 going to the live side they are separated laterally.

 

 

[IanR]

So my question here is - If you are a good pilot and you do the right thing, then why would a Unicom be a bad thing?

Kaz, Have been catching up on all this discussion. I agree that if used properly with good pilots it is great - only concern I sometimes have is that there are good and bad pilots out there. I fly at Camden which is controlled - and people still manage to regularly mess up !! I have copied in the VFR guide mention of UNICOMs for reference - the highlighted part must be the most important.

UNICOM (Universal Communications) is a non-ATS communications service

 

provided on the CTAF to enhance the value of information normally available

 

about a noncontrolled aerodrome.

 

The primary purpose of the frequency used for UNICOM where the frequency

 

is the CTAF is for pilots to be able to exchange relevant traffic information.

 

Services available from a UNICOM should be considered as secondary and

 

must not detract from the interchange of traffic information between pilots.

 

Persons providing a Unicom service are required to be licensed by the

 

Australian Communication Authority (ACA). Detailed information regarding the

 

licensing and use of equipment may be obtained by contacting the ACA in the

 

appropriate State or Territory capital city

 

Participation in Unicom services relates to the exchange of messages

 

concerning:

 

• fuel requirements;

 

• estimated times of arrival and departure;

 

• aerodrome information;

 

• maintenance and servicing of aircraft including the ordering of parts and

 

materials urgently required;

 

• passenger requirements;

 

• unscheduled landings to be made by aircraft; and

 

• general weather reports;

 

• basic information on traffic.

 

This information is available to all aircraft during the times that Unicom is

 

operating.

 

Weather reports, other than simple factual statements about the weather,

 

may not be provided by Unicom operators unless they are properly authorised

 

to make weather observations under CAR 120.

 

The Unicom operator is solely responsible for the accuracy of any information

 

passed to an aircraft, while the use of information obtained from a Unicom is

 

at the discretion of the pilot in command.

 

Unicom operators must comply with the requirement of CAR 83 (2).

 

 

[Matt]

I'm personally not aware of the concept of orbiting in the circuit at a non-towered aerodrome...and by "orbit" I assume you mean a 360 degree turn? Our training covered "go around" or "missed / baulked approach" for landing. Orbits were taught as being used outside the circuit area as a delaying action - we get plenty of these on approach to Canberra at peak hour for separation purposes. Similar might be used if inbound to a non-towered aerodrome i.e. orbit at 10 or 5nm for example to sequence into circuit traffic. As mentioned, orbits were taught as something that you did (or were directed to do) outside the circuit area.

 

In the above situation i.e. #3 and speedier than #2, I'd commence a go around to the right side (as I'm the overtaking aircraft) maintaining visual separation with #2 and depart the circuit area to hold until the situation (airfield temporarily closed) was resolved or divert to an alternate field. Another option would be to "hold" in the circuit pattern - effectively continue to fly the circuit at circuit height - and maintain separation to the right side of slower #2 if he was doing similar i.e. "holding" in the circuit pattern.

 

My thoughts...for what they're worth.

 

Cheers,

 

Matt.

 

 

[Guest browng]

I'm personally not aware of the concept of orbiting in the circuit at a non-towered aerodrome...and by "orbit" I assume you mean a 360 degree turn?

No, an orbit is just a circuit that is not a landing or a baulked approach, it is carried out as an alternative to a baulked approach if there is another aircraft (a) taking off from the runway with insufficient separation from the aircraft behind for that aircraft to complete a landing. (b) where the runway is blocked and an aircraft in front is already executing a baulked approach. It is not a 360deg turn, it is a complete circuit . A Go-Around is when the runway is clear and is carried out along the centerline. At least that is what I was taught back in the mists of time.

 

 

[Mazda]

Interesting posts!

 

For the B200 scenario, the pilots just look out and avoid the other aircraft! It isn't rocket science. Aircraft can fly slower or faster, circuits can be made wider, legs extended or shortened etc. I've been in a B200 in a busy circuit with slower aircraft and separation was maintained with no problems.

 

It's funny people preferring an AFRU to a UNICOM. When the AFRU came in people said they preferred a plain CTAF with no AFRU! AFRUs are great, but a real person would be better. And why not have both? A UNICOM operator when available, an AFRU when the UNICOM operator goes to lunch or finishes for the day.

 

I agree with Kaz. Anyone who blindly follows any instruction without thinking needs to reconsider. I've been told by ATC I had traffic in my 9 o'clock when it was in my 3 o'clock. People make mistakes and equipment can fail. The more resources we can use, the better, but we must still rely on our own judgment.

 

There was a terrible accident not long ago with a young solo student in the UK who was overloaded by ATC instructions and stalled while orbiting on final. We can all say that we can't comply with an instruction and we want something else (like a go around or a different runway).

 

As for a UNICOM operator giving an active runway that was not into wind, I watched an hour or so of flying at a busy CTAF recently and circuits were being done with a decent quartering tailwind the whole time!! It made for interesting entertainment! Aircraft in the circuit included a twin, a high performance tailwheel aircraft, and several GA types.

 

I've heard there is a new CTAF® discussion paper coming out, which seems to show one option being mandatory transponders for aircraft at airports with airline aircraft. Another option seems to be for UNICOMs. If that is true it sure is food for thought.

 

 

[Kaz]

No, an orbit is just a circuit that is not a landing or a baulked approach, it is carried out as an alternative to a baulked approach if there is another aircraft (a) taking off from the runway with insufficient separation from the aircraft behind for that aircraft to complete a landing. (b) where the runway is blocked and an aircraft in front is already executing a baulked approach. It is not a 360deg turn, it is a complete circuit

I would have to say you are incorrect. In controlled airspace an orbit is a 360 degree turn while maintaining altitude (we spend a lot of time doing them in Canberra waiting for sequencing). If you are in the circuit, turn base and are not going to land then it's called a go round, a missed approach, a pass (?) or something of that description.Working with air traffic controllers I am pretty confident of this terminology.

 

Can anyone else offer an opinion on this one???

 

 

[Kaz]

The following ATSB report contains reference to an aircraft orbiting while on downwind...

 

Breakdown of separation

 

Occurrence 200501921

 

On 30 April 2005, the pilot of a Cessna

 

Aircraft Company A152 (C152) aircraft

 

was conducting circuit training at Hobart.

 

The C152 was on the downwind leg of the

 

circuit when the crew of a Boeing Company

 

B717–200 (B717) aircraft commenced the

 

final leg of an instrument approach to the

 

same runway.

 

The Hobart aerodrome controller was

 

applying visual separation standards and had

 

instructed the pilot of the C152 to make

 

an orbit, and then continue downwind, to

 

separate the C152 from other aircraft. The

 

C152 pilot did not complete a full orbit,

 

but turned onto the base leg of the circuit

 

when the B717 was on final approach. The

 

minimum distance between the converging

 

aircraft reduced to between 400 and 500 m

 

horizontally and 300 ft vertically and required

 

the pilots of both aircraft to commence

 

avoiding action. There was an infringement

 

of separation standards.

 

 

[Mazda]

Kaz is right. An orbit is as it sounds - a circle. If you are told to orbit by ATC you just do a 360 degree turn. Sometimes they will amend this during the turn for sequencing, but the instruction is for a 360 degree turn, not a go around and circuit.