TERPS circling protected area
 

Hi everyone, a quick question for you FAA TERPS experts: as long as I can recall the protected area for Cat D circling aircraft was based on a 2.3 nm radius from the runway and 300' obstacle clearance. Recently whilst reviewing for a checkride I noticed my company Operations Manual now states that the protected area under TERPS for Cat D is 3.7 nm.

Has there been a recent change I was not aware of, or have I found an error in our sacred book? :)

MD

In a previous thread (I think the AirBlue) Aterpster indicated that a review of Terps circling areas was being looked at. Perhaps it has been? I don't think it has yet been published, though, but maybe your company has either jumped the gun or just decided it needs to change?

main dog:

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Hi everyone, a quick question for you FAA TERPS experts: as long as I can recall the protected area for Cat D circling aircraft was based on a 2.3 nm radius from the runway and 300' obstacle clearance. Recently whilst reviewing for a checkride I noticed my company Operations Manual now states that the protected area under TERPS for Cat D is 3.7 nm.

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It hasn't happened yet. At the last FAA/Industry Charting Forum they have finally agreed on the charting symbology that will be placed on an IAP that is in compliance with the new criteria, because the transition will likely take years (10 years in my estimation).

But, some housekeeping tasks remained to be done on the details of the chart symbology and how to best inform the aviation community.
So, for the time being (a very long time being in my view) it remains 1.7 for CAT C; 2.3 for CAT D.

When it does happen incrementally the areas will increase somewhat with airport elevation, thus a table explaining that in the AIP has to be finalized. 3.7 is a good ballpark figure for the incrementally future Cat D circling area.

Also, I am jaded, and still believe FAA internal politics will keep any of this from happening. I hope I am wrong.

Thanks gentlemen, sounds like someone has indeed jumped the gun...

A sensible jump, however, but the question you need to ask is from where do they get the new minima to reflect the enlarged circle?

BOAC:

I suspect the answer would be, "From the FAA's TERPs manual." The "new" CTL criteria were published with Change 21 a few years ago then placed on hold. The handbook is up to Change 24 now, so someone reading without knowledge of all the circumstances could reasonably conclude that the "new" CTL criteria are in effect.

Interesting, thanks, but I still think I would ask! Not all the managers making rules I have worked under are necessarily clever.

BOAC:

I agree. My history was hopefully to point the OP in exactly that direction.

- this is the really worrying part. Some circling minima (altitudes) must change in this situation. IF main dog is 'unaware', where is the 'Special Notice' or whatever to all crews and where does he/she find the new Circ minima - if on the charts, which provider has the new surveys??

Main Dog?

The first I was aware of this "new" protected area was when I recently noticed the number 3.7 instead of 2.3 nm in our manuals. Since I had not heard of this before, and there were no relevant notices to crew or any other such communication, I started looking online and couldn't find any FAA reference either. Thus I turned to you esteemed gentlemen!

Next step, ask Line Ops what they're on about...

Not being a jet pilot I googled the topic and found this article from last year..

Dangerous Approaches | Flight Safety Foundation

- yup! I would also suggest NOT using the new area until you are sure the minima apply.

An excellent article Cwatters - hadn't seen it before. A good example of the problems it highlights is one of our regular destinations - Busan in Korea. Terps minima, fatal if flown to PANSOPS - as an Air China crew found out in 2002. it doesn't help that some airports in Korea use PANSOPS (Incheon and Gimpo) and others such as Busan use TERPS. Not all understand that. When our larger neighbour bough us a few years ago, we adopted their Ops manual which confidently stated that all airfields in Korea use PANSOPS. They only flew to Incheon!

Busan now has a giant checkered board on that terrain north of the airport as well as a series of lead-in lights.

Busan now has a giant checkered board on that terrain north of the airport as well as a series of lead-in lights.

This seems to be an odd safety response – the hazard still exists (short of bulldozing a mountain).
Wouldn’t the use of a PANSOPS procedure and higher circling altitude be more effective?

This is a “How can we do this”’ solution opposed to “Should we be doing this” safety response.

PEI:

I agree with you.

Even at 2.3 miles radius, the circuit height is 1100'. At the PANSOPS radius of 4.6 miles, you will have to fly round finals at about 2000'! It's just not feasible as the hill in question is on the centrline.

Re the TERPS/PANSOPS argument:

You first need to eliminate the 'Arizona/John Wayne' state of mind that TERPS circling is for real men.only and 'if you cannot stand the heat'..............

It does sound as if commonsense is lurking in the cactus bushes in the US of A, however. No-one is suggesting that PANSOPS is the 'best' solution but it is certainly safer.Having done a few TERPS circles the last thing I want in difficult weather in a circle is the added pressure of having to stay within a very tight area.

Agree. To fly a 737 and keep inside 1.7 nm from the runway while allowing for drift and at the minimum vis for circling, can be bloody dangerous. The critical obstacle that defines the published MDA for circling may not be displayed on the instrument approach chart that led to the circling manoeuvre in the first place. It could even be just outside the approach landing splay and invisible at night.

Received wisdom is you don't commence descent below the circling MDA until lined up on final hopefully with a VASIS or PAPI available. But with circling MDA's varying greatly for example from 1500 ft agl to as low as 700 agl, then in order to keep within the protected area for a 737 category, the pilot may be forced to commence descent below the MDA well before he is lined up.

The danger of that is obvious unless the pilot is familiar with the local terrain. The ICAO published protected area around an airport allows a much safer operation; even though occasionally it may result in a higher circling MDA than closer in. A small price to pay for a significant safety factor increase.

BOAC:

The NTSB and the FAA reached a conculsion sort of like that when an American Airlines 707 crashed on the downwind leg of a circle to land at a relatively flatland airport, KCVG. (1965 or thereabouts.)

And, within a few years the FAA prohitbited circle to land for commercial operations unless specific training is provided.

Dan Winterland:

It's only a matter of time until the new, much larger TERPs CTL criteria catches up with them.

OKC465:

My memory didn't do me well on that AAL CVG crash.

I guess 121 was different. I had four rating rides during my career. The first two were in the airplane (1967 and 1969) because the sims weren't qualified. The second two were all sim (1983 and 1986.) We didn't do any CTL either on the rating ride or on any PC.

My cerificate wasn't marked either. I understand they started doing that sometime after my last rating in 1986.

The Australian Air Services AIP has one of the most misleading paragraphs I have seen on the conduct of circling approaches and this is taken from ICAO. Discussing when to descend below the circling MDA for landing it says:

"While complying with (visual obstacle clearance) ...by day or night....at an altitude not less than the MDA, descent below the MDA may only occur when the aircraft intercepts a position on the downwind, base or final leg of the traffic pattern and from this position can complete a continuous descent to the landing threshold using rates of descent and flight manoeuvers which are normal for the aircraft type and during this descent maintaining an obstacle clearance along the flight path not less than the minimum for the aircraft performance category until the aircraft is aligned with the landing runway."

It means at night the pilot must be able to see the ground ahead and below in order to maintain minimum published terrain clearance until on final.

While the AIP is clear in the intent that the pilot must be able to gauge his height at night above terrain, he will almost certainly be unaware of the position of the critical obstacle that dictates the MDA. Therefore, to plan on deliberately descending below the circling MDA merely to suit the ideal glide path profile downwind, or base (which has nothing to do with terrain clearance but more to do with profile handling) - has led to unnecessary risk taking because once the pilot has left the published circling MDA he is entirely responsible for his own obstacle clearance. Unless the pilot is familiar with the position of terrain (such as over water or flat ground) at night, then it is wise to stay at the circling MDA until established aligned with the landing runway.

There are some fundamental & substantial differences between the TERPS & PANSOPS Circling procedures!

See: http://www.skybrary.aero/index.php/C...S_and_US_TERPS

Tee emm:

If the MDA is too high for the pilot to remain at it until turning final and then make a normal descent for landing (while remaining within the lateral limits of protected airspace) then descent below MDA must necessarily occur on base leg or perhaps even late downwind.

The sensible answer is to circle in such circumstances only at an airport and to a runway where you have current and good local knowledge. Otherwise, you are asking for an accident.

Why is the MDA for CTL so high at some airports? Usually big rocks, sometimes a tower. But, a tower can usually be avoided by the designers by restricting CTL to one side of the runway.

Contrary to some folks opinions, CTL can easily become a high risk operation, more so at some airports than others. Less so if the pilot is very familiar with the airport environs and is at the top of his game.

- Concur- an 'incident' I recall many years back at RAF Leuchars in Scotland where a visiting Canberra flew a left-hand night visual circuit on R09, mantaining a direct, clear line of sight to the threshold, and actually rubbed his wingtip tank on the side of Lucklaw Hill (fortunately the side sloping towards the runway.......) half way around finals.................................:eek:

There are many IAPs in the mountain areas of the U.S. where the circling MDA is very high, not because of rocks in the CTL maneuvering area, but because of penetrations of the standard missed approach surface. In the latter case the pilot has lots of clearance in the CTL area, but this isn't really apparent unless the pilot is familiar with the airport.

Where I used to fly, KSEE, was a good example of a relatively high CTL MDA. Admittedly, I just flew a light twin in there but I believe even the bigger jets (Gulf 5, Falcon 900 etc.) had to start their descent on downwind to manage their profile. Overshoot the final for 27R, you would hit the biggest rock in the vicinity of the field. Also if a balked landing was to be executed the published missed approach procedure would not be a very good idea since it would take you approximately right over the highest point (Cowles Mountain for the locals) direct to MZB VOR. Runway only 1615 m. Easy to paint yourself into a corner on a bad day, I can imagine. A basic VFR pattern south of the field might be the best idea. Local knowledge about the terrain is certainly useful.

Are there any procedures laid out at all for balked landing go-arounds below MDA during CTL? Missed approach procedures do not really take that into account, do they?

172 driver:

Nope, you're solo. The U.S. AIM does discuss it. In some cases they advise reverting to the ODP. That may result in a lot of problems including a climb gradient problem for a small airplane.

Any more than they provide G/a patterns below DA on an ILS. Salzburg is a good example (LOWS) where the g/a for the special (200'DH) ILS is quite different to the higher 'normal' ILS due terrain.

Don't forget that in the process of manoeuvring onto the g/a for the 'other' runway if you wish to escape (visually, of course..............) you will be gaining height. Also worth remembering that there is nothing to stop you joining the visual circuit or another 'circle', but that if it is night, it is not a good idea to turn onto the g/a track OR downwind until you are at circling minima.

Received Wisdom?
 

Centaurus,

I presume you are talking about TERPs circling. Or is that what you are teaching for PANSOPs? :eek:

Stay Alive,

BOAC, the only difference in LOWS is a max speed and advise until which altitude you cannot accelerate during the turn, isn't it? Depicted groundtrack and procedure wording is the same though.

LOWS - I have not looked at the plates since 2007/8 but then there was a different ground track. It must have changed.

Just checked - yes, they appear to have 'standardised' all approach g/a tracks since then apart from different speeds/bank (so I reckon it is still valid) - I always briefed the 'CatIII' g/a for a baulked landing.

Surely the solution to that situation is to divert - since descending below the circling MDA at any point other than within the protected area in the final approach splay, is potentially dangerous - unless the pilot can ensure legal terrain clearance for the category of aircraft.

Don't miss the rest of that post?

We need just regular training in the simulator, for example this year we do our CAT III training in SZG. But it is not even required every year.

English Dictionary -Geddes & Grosset - New Edition. Page 352.
"Received"...ad. accepted, recognized':ok:

Slight hijack of the thread here, but my types are all unrestricted (no DAY VMC ONLY circling limitations). Now, if I am flying with a FO who does have this restriction on their certificate am I now limited by their certificate?

Av. I'd say you're to go with the most restrictive crew authorization. That's one of the reasons why Chinese require no circling restrictions on license. Same story goes for both pilots having unrestricted licenses but one not being qualified for the airdrome. Best example I can think of being CIA. VOR A is a circling approach using prescribed tracks. :ok:

Good old common sense will get you to the runway once in VMC conditions. Making restrictions like staying at MDA until turning final only causes you to be high and unstabilized. Any decent pilot can determine in visual conditions where he should be to make the approach work properly. Don't make something easy hard.