Approach Category

MikeOH58

MikeOH58

Well-Known Member
Using 1.3 x Vso, an aircraft is approach category A. Lets say the pilot decides to fly the approach at 110 knots. Does he/she now us Category B minimums, or do you continue with Cat A?

I've gone and confused myself. Right now i'm thinking you continue to use Cat A minimums. The only time you increase would be on a circling approach. You would still use Cat A wx criteria, but increase max circling distance to 1.5 miles.

How off am I?
 
MikeOH58 said:
Using 1.3 x Vso, an aircraft is approach category A. Lets say the pilot decides to fly the approach at 110 knots. Does he/she now us Category B minimums, or do you continue with Cat A?

I've gone and confused myself. Right now i'm thinking you continue to use Cat A minimums. The only time you increase would be on a circling approach. You would still use Cat A wx criteria, but increase max circling distance to 1.5 miles.

How off am I?
Click to expand...

If you are using a higher airspeed for the approach, then yes, you would bump your numbers up accordingly. My aircraft is a cat C jet, but when we do section formation approaches (using higher speed), we use the cat D numbers for mins.
 
Okay so you are saying that not only the circling protected radius, but also Wx minimums are dependant on the speed actually being used.
 
Aircraft category is determined by using 1.3 times VSo OR the highest speed to be used during the approach/circling maneuver.
 
MikeOH58 said:
Okay so you are saying that not only the circling protected radius, but also Wx minimums are dependant on the speed actually being used.
Click to expand...

Correct, that is my understanding (at least in cases where you are dealing with different mins depending on category). The protected radius is the reason for the higher mins in those cases, so they kind of go hand in hand.
 
shdw said:
I don't recall reading a regulation that says you must use the category for the speed you are flying. I believe that is an AIM recommendation, been a while.
Click to expand...

You can be flying a 172 and fly Cat E minima if you like, just use the appropriate MDA, and for circling you can use the respective radii.
 
I've always used Category B in the planes I've flown. I can count on one hand the number of times I've flown an approach under 90 knots. On the approaches I've flown I can't recall any of them that have big differences in Cat A/B minimum's.
 
KSCessnaDriver said:
I've always used Category B in the planes I've flown. I can count on one hand the number of times I've flown an approach under 90 knots. On the approaches I've flown I can't recall any of them that have big differences in Cat A/B minimum's.
Click to expand...

I don't think it works in that direction. It seems like you're talking about lowering your category, and the OP is talking about raising his category. I think lowering your category (from Cat B to Cat A, for example) is always against the rules. I can't quote a chapter and verse on that, though, so I'm not 100% on that. Still, I always hear about this question the other way... category increases, not category decreases.
 
fish314 said:
I don't think it works in that direction. It seems like you're talking about lowering your category, and the OP is talking about raising his category. I think lowering your category (from Cat B to Cat A, for example) is always against the rules. I can't quote a chapter and verse on that, though, so I'm not 100% on that. Still, I always hear about this question the other way... category increases, not category decreases.
Click to expand...

Wasn't saying I go from B to A. I've never flown something that wasn't a Category A. Should have made that clear from the beginning. I just can't stand people who enjoy flying an ILS at 70 knots.
 
fish314 said:
I don't think it works in that direction. It seems like you're talking about lowering your category, and the OP is talking about raising his category. I think lowering your category (from Cat B to Cat A, for example) is always against the rules. I can't quote a chapter and verse on that, though, so I'm not 100% on that. Still, I always hear about this question the other way... category increases, not category decreases.
Click to expand...

FAR 97.3

(b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at the maximum certificated landing weight. VREF, VS0, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry.
 
it is the paragraph before the approach category chart on the 2nd page of NOS approach charts. It says to use 1.3xVso or the speed on the approach (i parphrased, mine are in my car)
 
Blackhawk said:
FAR 97.3

(b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at the maximum certificated landing weight. VREF, VS0, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry.
Click to expand...
So, since we have a ref speed specified...at MLW, we're Cat C. Does this mean at 8000 pounds-ish (with a ref of 89) I can use cat A?

...it's a "specified" speed of VREF

-mini
 
Xiph said:
Hmm, sounds like it.
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That's what I always thought. Otherwise, why put in the part about "Vref, if specified..."?

However, the common thought process in everyone I've ever talked to is "you can fly it at 89, but it's still a Cat C airplane for an approach."

If that were the case, then why have the "Vref, if specified"?

If you wanted to take it further, we could probably get into Cat D heavy with flaps up and no Thrust Attenuators. That doesn't mean we're always a Cat D airplane.

-mini
 
MikeOH58 said:
Using 1.3 x Vso, an aircraft is approach category A. Lets say the pilot decides to fly the approach at 110 knots. Does he/she now us Category B minimums, or do you continue with Cat A?

I've gone and confused myself. Right now i'm thinking you continue to use Cat A minimums. The only time you increase would be on a circling approach. You would still use Cat A wx criteria, but increase max circling distance to 1.5 miles.

How off am I?
Click to expand...

Simply use the category based on the speed in which you're flying. In your example, using Cat A weather minimums while expanding the maximum circling distance to 1.5 miles can be dangerous. The circling minimums are typically raised as the category goes up, simply because there are more obstacles the further you get from the threshold.

For example, let's say that an approach has circling minimums as such:

Cat A: 500 AGL, 1sm visibility
Cat B: 700 AGL, 1-1/2sm visibility

If you're flying the approach at 120 knots (putting you at the top of category B), would you still go down to 500', even though you may be using every bit of that 1.5nm due to speed? What if there's a 600' TV tower 1.4 miles from the threshold?

Don't mix and match. Just fly what's on the chart.
 
minitour said:
That's what I always thought. Otherwise, why put in the part about "Vref, if specified..."?

However, the common thought process in everyone I've ever talked to is "you can fly it at 89, but it's still a Cat C airplane for an approach."

If that were the case, then why have the "Vref, if specified"?

If you wanted to take it further, we could probably get into Cat D heavy with flaps up and no Thrust Attenuators. That doesn't mean we're always a Cat D airplane.

-mini
Click to expand...

If the airplane is certified as a Cat D airplane then it's a Cat D airplane. You can go up, but not down. This is an issue for the CRJ which was almost a Cat E airplane.
 
Blackhawk said:
If the airplane is certified as a Cat D airplane then it's a Cat D airplane. You can go up, but not down. This is an issue for the CRJ which was almost a Cat E airplane.
Click to expand...
Explain...

Blackhawk said:
FAR 97.3

(b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at the maximum certificated landing weight. VREF, VS0, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry.
Click to expand...

Why even include that if you're only going to use 1.3 Vso at MLW for your numbers?

If my numbers say I'm 89 knots, why am I not cat A but still stuck in cat C? That's the "specified" Vref.

I'm not saying you're wrong, because (as I said earlier) I've heard it spewed as gospel before from many. I just want to know "why?".

-mini
 
minitour said:
Explain...



Why even include that if you're only going to use 1.3 Vso at MLW for your numbers?

If my numbers say I'm 89 knots, why am I not cat A but still stuck in cat C? That's the "specified" Vref.

I'm not saying you're wrong, because (as I said earlier) I've heard it spewed as gospel before from many. I just want to know "why?".

-mini
Click to expand...

"Because I said so" is not good enough??:rolleyes:

From the Instrument Procedures Handbook:
"V​
​
​
​
REF refers to the speed used in establishing the approved landing distance
under the airworthiness regulations constituting
the type certification basis of the airplane, regardless of​

whether that speed for a particular airplane is 1.3...

An airplane is certified in only one approach category, and
although a faster approach may require higher category
minimums to be used, an airplane cannot be flown to the
minimums of a slower approach category. The certified
approach category is permanent, and independent of the
changing conditions of day-to-day operations. From a
TERPS viewpoint, the importance of a pilot not operating
an airplane at a category line of minimums lower than the
airplane is certified for is primarily the margin of protection
provided for containment of the airplane within the
procedure design for a slower airplane. This includes
height loss at the decision altitude, missed approach climb
surface, and turn containment in the missed approach at
the higher category speeds. Pilots are responsible for
determining if a higher approach category applies. If a
faster approach speed is used that places the aircraft in a
higher approach category, the minimums for the appropriate​
higher category must be used."
 
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