Aircraft approach category question

[de facto]

Citation2


You are confused because the same name (aircraft category)is used in both the approach category (straight in)and the circling maneuver.


A category of an aircraft is dependent on its VAT ..not the circle!!!!!!!!!

I recall a question that many examiners ask during oral test, or type rating : what is the maximum speed allowed in a circle to land for a C aircraft? Answer : 180 kts.

It is a wording issue,a B737 with a mac landing weight of 65.3T(cat C) may have to perform a circle at higher speed than 180 kts due to flap failure,(lets say 200kts),it will use cat D minima(higher MDA) even though it is STILL a CAT C category.
Get it?

AerocatS2A

Join Date: Jan 2004
Location: Australia
Posts: 1,595
Jeppesen Aus states you can circle at a higher category if you wish provided you comply with the restrictions for the higher category. Basically if you need more room to manoeuvre you can use the larger circling area of a higher category provided you also use the higher obstacle clearance altitude.

Correct!
Your aircraft is still a CAT C (this will NOt change,its fixed by the operator)but you as pilot may use CAT D CIRCLING minima because of higher SPEED due to flaps malfunction for example.

Likewise if your aircraft only just fits into a Cat at max landing weight you can't drop down when at a lower weight.

Correct.

[9.G]

Aircraft approach category - Wikipedia, the free encyclopedia. It's the actual speed for the circling. As already mentioned I can fly it in clean config due to whatever reason but gotta use minima accordingly.

[Citation2]

De facto: I think you misunderstood me. This is from Airbus FCTM
"The circling area which ensures obstacle clearance is based on a maximum speed of 180 kt for Category C aircraft (ICAO PANS-OPS and JAR OPS) "

If you are in an abnormal situation such as flap failure your Vref is going to be directly affected.On A320 , flaps 0 landing will result in a Vref+60 . So you will obviously be in a higher Category , because the Vref was directly affected and not because you chose to fly faster in a portion of the approach.

Not even talking about circling, If in abnormal condition your vref ( vref is Vat or speed at threshold) is let's say 165 kt even for a straight in ILS approach, you will use D category.

Now in normal situation regarding circle to land , you will not change your aircraft category because you are flying faster as a maximum speed has been taken into consideration for each cat A, B , C, or D

If your final approach speed Vref is within 121 and 140 kts, You are in the C category , you are allowed to fly up to 180 kt in a circle to land.

If your Vref is between 141-165 kt, you are in the D Category, you are allowed to fly up to 205 kts in a circle to land.

This is PAN OPS regulation and how obstacle clearance is calculated using the Max speed for the category.

You could be doing a low as 121 kts on final, but ICAO designed for you a circle to land protection based on 180 kt, without the need of changing your category. This has been catered for in PAN OPS

FAA, terps approach have different rules and do not have such wide protections as PAN OPS. So if you are doing 180 kts in a circle to land designed according to TERPS, you will have to use the next higher category.

If you are performing a circle to land designed according to PAN OPS regulations , wider protections with max speed are provided without having to go on the next higher category.

Airbus FCTM :In regions where FAA TERPS criteria apply, the circling areas and limit speeds are more restrictive

[roulishollandais]

Pansops is not an OACI recomandation but a work document. Each State does its national regulation wich is published. Reserves can be done to the annex and must be declared.

Wiki is not a reference!!

[westhawk]

A real world example of how to determine which minimums are applicable to your aircraft for an IAP according to FAA guidance:

Lear 60 max ldg wt Vref = 139 KIAS. Airplane is an approach category C aircraft. Aircraft only fit into ONE approach speed category according to the MLW Vref or 1.3 Vso. The LR60 is a Cat C aircraft. Cat C landing minima are the lowest which may be used. However if the approach speed to be flown is greater than 140 KIAS then cat C minima is no longer applicable. The minima which are applicable to the ACTUAL approach speed to be flown during the approach MUST be used.

A typical situation encountered on a routine basis might go like this:

A single runway airport has a GPS-A as it's only published IAP. No straight-in mins are published and circling will be required. Calculated Vref at arrival weight will be 136 KIAS. For circling the 60 a speed of Vref + 12 (Vac) is indicated so Vapp will be 148 KIAS. Therefore the Cat D minima are the lowest which may be used even though the LR60 is certified as a Cat C aircraft. Clear as mud now? Anyway that's how we have to do it in FAA land unless we were flying in the airspace of another country with more restrictive rules. We are obligated to respect whichever is more restrictive.

Best,

westhawk

[de facto]

Citation 2 i see what u mean now, yes i agree,if flap failure your vref will be affected during a circling maneuver and you will be restricted to a max speed ie 205 kts if your vref was lets say 195 kts.your aircraft even thou being cat c ,you will fly cat d minima.
Cat C in that condition is STILL you certified approach category though.

I fully agree with westhawk post above.

[aterpster]

Citation:

You could be doing 160 kts on final or 180 kts in a circling , you are still in C category as long as your Vref is within 121 -140 kts at threshold.

You obviously don't have a handle on the situation.

My "clueless" airline was TWA, that owned some 50 727s and had a very close relationship with Boeing.

I believe it was the way the airplane was certified but I am not sure of that. What I am sure of is TWA's prescribed speed for the 727's CTL procedure fell into Category D, at least at, or near, max landing weight.

[737-NG]

Have not studied the JAR nor ICAO rules yet but FAA says a circling approach must provide a minimum of 300 feet of obstacle clearance within the circling approach area. The size of this area depends on the category which the aircraft operates.

Category A= 1.3 mile radius
Category B= 1.5 mile radius
Category C= 1.7 mile radius
Category D= 2.3 mile radius
Category E= 4.5 mile radius

Digging deeper into my FAR/AIM I get this from CFR Part 91:

"An aircraft can only fit into one approach category. If it is necessary to manoeuver at speeds in excess of the upper limit of the speed range for each category, the minimum for the next higher approach category should be used"

So a Cat C aircraft would become Cat D, and so on.

But I do think Citation2 has a point.(règles DGAC-JAR je suppose??)

[de facto]

"An aircraft can only fit into one approach category. If it is necessary to manoeuver at speeds in excess of the upper limit of the speed range for each category, the minimum for the next higher approach category should be used"

Agree.only one certified approach category but minima of a higher may be used due to non normal higher SPEED (which indirectly comes from a higher VREF.)

So a Cat C aircraft would become Cat D, and so on.

No you dont become cAt D,you remain cat C but you use cat D minima.
Your catc is FIIIiiIiIiIiXxxxxxxED by operator/regulator!

The radius of protection you showed is for TERPS,PaNOPs are wider.

[737-NG]

Oooh come on de facto, you know what I meant!

[9.G]

C2, there're 2 types of approaches straight in and circle to land.
Aircraft categories are defined for a straight in, as you've stated, as per Vat.
Circling, missed approach and take off aircraft categorization is defined with max speed for maneuvering. The relevance of this is that for a straight in approach you'll use the minima for the declared category by the operator regardless of the Vapp flown whereas for circling you'll apply the minima for the actual speed flown. Best example for that, again as you stated, is when you're CAT C for a straight as per PANS OPS but gotta fly a circle to land as per TERPS. Automatically you'll be in the cat D for circling thus using CAT D minima.

[BOAC]

This is a very complex and confusing situation needing careful attention and not helped by posters here who are not stating whether their figures are TERPS or PANSOPS. I am having difficulty finding references for TERPS approach categories - I have always assumed they are the same as PANSOPS which I believe are ICAO - 90/120/140/165. Can anyone confirm?

The main area of confusion for me is in circling - PANSOPS max speeds are clearly defined - 100/120/180/205. . I cannot find TERPS. Posters above (9.g + westhawk) are suggesting that TERPS max circling speeds are the same as the TERPS approach category speeds - is this correct?

FAA/ICAO links would be nice.

[aterpster]

Federal Aviation Reg: § 97.3 Symbols and terms used in procedures.

As used in the standard instrument procedures prescribed in this part--

Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 Vso at the maximum certificated landing weight. VREF, Vso, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry. The categories are as follows--

(1) Category A: Speed less than 91 knots.

(2) Category B: Speed 91 knots or more but less than 121 knots.

(3) Category C: Speed 121 knots or more but less than 141 knots.

(4) Category D: Speed 141 knots or more but less than 166 knots.

(5) Category E: Speed 166 knots or more.


FAA Aeronautical Information Manual:

5-4-7. Instrument Approach Procedures

a. Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VSO at the maximum certified landing weight. VREF, VSO, and the maximum certified landing weight are those values as established for the aircraft by the certification authority of the country of registry. A pilot must use the minima corresponding to the category determined during certification or higher. Helicopters may use Category A minima. If it is necessary to operate at a speed in excess of the upper limit of the speed range for an aircraft's category, the minimums for the higher category must be used. For example, an airplane which fits into Category B, but is circling to land at a speed of 145 knots, must use the approach Category D minimums. As an additional example, a Category A airplane (or helicopter) which is operating at 130 knots on a straight-in approach must use the approach Category C minimums. See the following category limits:

1. Category A: Speed less than 91 knots.

2. Category B: Speed 91 knots or more but less than 121 knots.

3. Category C: Speed 121 knots or more but less than 141 knots.

4. Category D: Speed 141 knots or more but less than 166 knots.

5. Category E: Speed 166 knots or more.

[Fullblast]

C2, there're 2 types of approaches straight in and circle to land.
Aircraft categories are defined for a straight in, as you've stated, as per Vat.
Circling, missed approach and take off aircraft categorization is defined with max speed for maneuvering. The relevance of this is that for a straight in approach you'll use the minima for the declared category by the operator regardless of the Vapp flown whereas for circling you'll apply the minima for the actual speed flown. Best example for that, again as you stated, is when you're CAT C for a straight as per PANS OPS but gotta fly a circle to land as per TERPS. Automatically you'll be in the cat D for circling thus using CAT D minima.

Agree with you, it might be just wording, but to me some posters are saying something different. It seems that someone is upgrading the straight-in app. minima in case of higher Vref.
You say Vapp, that's not the same as Vref, what do you exactly mean?

FB

[BOAC]

Thanks - that confirms a significant difference between ICAO and TERPS. Under ICAO, the max circling speeds are separately defined. Under TERPS they relate to Approach category, which for most 737/AB drivers NB puts you in Cat D for all circling on TERPS, eg Greece (I believe still??), Israel, and North Am.

Incidentally, the FAA doc may be out of date as it does not mention 1.23 Vs1g - or is this not recognised in FAA land?

[27/09]

aterpster

If it is necessary to operate at a speed in excess of the upper limit of the speed range for an aircraft's category, the minimums for the higher category must be used.

For example, an airplane which fits into Category B, but is circling to land at a speed of 145 knots, must use the approach Category D minimums. As an additional example, a Category A airplane (or helicopter) which is operating at 130 knots on a straight-in approach must use the approach Category C minimums. See the following category limits:

The first part of of you post that is highlighted is correct however you are using the wrong speeds when selecting which category minima applies.


As you stated a Cat B aircraft is one where VRef falls between 91 and 120 kts. However the maximum speed inside the final fix for a Cat B aircraft is 130 kts and max circling speed is 135 Kts so the Cat A aircraft operating at 130 kts can use Cat B minima for the straight in approach and not Cat C as you stated.

The Cat B aircraft you mention at 145 knots can use Cat C circling minima as the max Cat C circling speed is 180 knots.

The table in this Wiki article lays it out quite clearly.

Aircraft approach category - Wikipedia, the free encyclopedia

With further reading I see the FAA and some other jurisdictions do it differently and just as aterpster quoted.

It's just as well we all do it to the book, just depends on which book.

[de facto]

BOAC,

TERPS and PANOPS both group aircraft into categories based on VREF.
PANOPs is using higher speeds for circling (ie cat C up to 180kts) hence a larger radius required (max 4.2 rather than 1.7NM for USTERPS).
Min vis PANOPS circling is 2NM , USTERPS is less(1.3NM).

I cannot find TERPS. Posters above (9.g + westhawk) are suggesting that TERPS max circling speeds are the same as the TERPS approach category speeds - is this correct?

I believe it is ,as there is no mention of any difference and required visibility is lower for USTERPS,which makes sense as your radius clearance is also lower.

[aterpster]

27/09:

The first part of of you post that is highlighted is correct however you are using the wrong speeds when selecting which category minima applies.

I am not using anything. That is a direct quote from the FAA's Aeronautical Information Manual. I did add the bold for emphasis, however.

[9.G]

Fullblast, it's Vref sorry I just used airbus term. Vapp is Vref+approach correction. However that's not the point. The point here is how to use this classification on a daily basis. Let's take an example of a A 321 with higher gross weight fitting into CAT D for a straight in. We fly IAP as per PANS OPS 4. Now, what minima will be applicable for circling? Is it CAT D or C? Surely with flaps 3 and gear down the IAS during circling won't be higher than 180 Kts will it? IN this case for a straight in I must use CAT D minima and for a circling I can elect to use CAT C. On the the other hand A 330-CAT C with flaps/slats stuck at 0. Which minima is applicable for a straight in and for a circling? Is it CAT C or D? IAS flown in this case is 182Kts. I've seen some guys using CAT C for a straight-in others used D. Which one is correct that's the question? It's definitely D for circling though. Funny enough if you look at the approach plate straight-in landing minima has only reference to the aircraft category whereas circle to land to the max Kts. IAS.

BOAC, glad you got figured that one out.

[BOAC]

I think having looked deeper, even the FAA appear confused!

I have yet to see, on a TERPS chart (JEPP) any circling minima defined by Approach Category, simply by circling speed which is a far better and easily applied figure. Thus in FAAland, where 5.4.7 states 'must use the approach Category D minimums' for circling it is not necessary, since speeds are the governing factor both under PANSOPS and TERPS, and are tabulated on chart minima for TERPS. The one thing a pilot will readily know is the speed at which he plans to circle, be it iaw SOP or with some particular situation on the day. In Pansops you are 'required' to know and apply the max circling speeds for each approach category.

Apart from the often discussed idea of 'harmonising' circling areas between TERPS and PANSOPS, I do feel it is time for a change, preferably by PANSOPS, to display circling minima based clearly on circling speeds rather than 'approach category'. IE For a 'Cat C approach a/c' (eg 737-700) why not have PANSOPS display minima for '180/205' instead of 'Cat C/Cat D'.

What say the masses? Will it make life simpler?