Approach/Landing category and Vref

[leonard17F]

Dear Ppruners

Need to refresh my memory:
Is the approach Category defined by the speed at Max Landing Weight or by the ACTUAL weight ? I.e. Is it fixed or does it change according to actual scenario ?

And if you add knots because of other considerations, crosswind or turbulence for example, do you have to bump up your Category ?

Thanks a million !

Leo

[Denti]

Probably depends on the rules which you have to follow. Having flown only under european rules, the category was always fixed for me, although there were some weird things, like category C, except for circling which was D on our 733s.

[aterpster]

Is the approach Category defined by the speed at Max Landing Weight or by the ACTUAL weight ? I.e. Is it fixed or does it change according to actual scenario ?

Fixed by certified structural max landing weight (the landing weight when not runway limited).

In the U.S. at least, if you elect to fly the approach at a higher category speed then you are bound by the minimums for that election.

There is one business jet I am aware of (one of the Gulfstream models) that are Category D for straight-in, unless they depart knowing they will land at less then a specified weight. They then activate some certified placard that places them in Category C for that flight.

Denti: the 727 was that way, certified for Category C for straight-in, D for CTL.

[Check Airman]

aterpster,

I'll have to go look up a reference, but isn't the approach category determined by Vef at the actual landing weight, and not the maximum?

[Too Few Stripes]

The category is fixed under EASA, ref-

Cat.op.mpa.320 aircraft categories

(a) Aircraft categories shall be based on the indicated airspeed at threshold (VAT) which is equal to the stall-ing speed (VSO) multiplied by 1.3 or one-g (gravity) stall speed (VS1g) multiplied by 1.23 in the landing con-figuration at the maximum certified landing mass. If both VSO and VS1g are available, the higher resulting VAT shall be used.

(b) The aircraft categories specified in the table below shall be used.

table 1: aircraft categories corresponding to Vat values

aircraft category Vat

A Less than 91 kt

B From 91 to 120 kt

C From 121 to 140 kt

D From 141 to 165 kt

E From 166 to 210 kt

(c) The landing configuration that is to be taken into consideration shall be specified in the operations man-ual. (d) The operator may apply a lower landing mass for determining the VAT if approved by the competent authority. Such a lower landing mass shall be a permanent value, independent of the changing condi-tions of day-to-day operations.

[aterpster]

Check Airman:

FAR 97.3

[Cak]

ICAO PANS-OPS Doc. 8168 is clear about this:

Speed at treshold at MAXIMUM landing weight

[Cak]

ICAO PANS-OPS Doc. 8168 is clear about this:

Speed at treshold at MAXIMUM landing weight

Same as EASA regulation

[Check Airman]

aterpster,

Thanks for the link. I still disagree with you though, based on the wording in 97.3

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 way I read it is that if Vref is not specified, then you use 1.3*Vso at MLW.

My understanding of it in practical terms is that a light aircraft which doesn't have a published Vref (eg C172) would use 1.3*Vso at MLW, and so would always be in the same category. A larger aircraft has published values for Vref, and so the category would depend on weight.

Am I way off the mark here? If I'm not mistaken, you have a background in procedure design, so I'm interested to hear your take.

[donstim]

Check Airman,

See https://docs.google.com/viewer?url=h...rpretation.pdf

[Check Airman]

Thanks for that link. It certainly explains aterpster's (and the FAA's) position. They should re-write 97.3 in that case, because what they meant isn't really what they've said.

[aterpster]

The conclusion is consistent with 97.3:

"We therefore conclude that for aircraft grouped by speed of V REF aircraft approach category must be determined using speed of VREF at the maximum certificated landing weight."

BTW, I recall that document when it published. The attorney's history is wrong. TERPs was adopted in November, 1967.

[leonard17F]

Thanks a lot everybody !

Just to make sure I understand:
- if you are NOT runway limited, you would use the Vref at MLW
- if you ARE runway limited, you would use the Vref for the "actual" MLW
- you NEVER use the actual landing weight
- if you perform a circle to land and/or use a different flap settings which will induce a higher Vref, you will use the new Vref, still at Max Landing Weight for that configuration, hence higher minimas

Am I correct ?

Leo

[Cak]

I don't think you can choose a category by yourself . If you are limited by runway or something else, you need to have approval from the authority to use a lower category. Category should be a permanent value, not regarding of actual speed and actual weight

[aterpster]

Cak:

I don't think you can choose a category by yourself . If you are limited by runway or something else, you need to have approval from the authority to use a lower category. Category should be a permanent value, regarding of actual speed and actual weight.

Exactly. Approach category is determined in certification. If I am very light one day I cannot elect a lower category because Vref fits that lower category with today's landing weight. But, on the flip slide, if I elect to fly at a higher category speed I am then bound by the minimums for that higher category.

[leonard17F]

Got it !
Thanks a million !

[PilotBr]

Hi folks, I understood that the app category is based on VREF in the MLW, right? I have a question regarding the configuration, I'm flying the Airbus 320, in conf FULL it's category C, but in conf 3 the speed will increase 5 knots, so it'll enter in category D.
Can you help me with this question?

Thanks