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Old 27th Dec 2012, 00:31   #21 (permalink)
 
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FlightPath...

Of course a procedure is designed to accommodate aircraft but the point I'm trying to make is that it's incorrect to say that a procedure was designed for an airplane operating on all engines and therefore not designed for an airplane operating OEI.

A procedure is designed with certain performance requirements. If an aircraft can meet those performance requirements then it can safely follow the procedure. It doesn't matter how the aircraft attains that performance!
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Old 27th Dec 2012, 17:21   #22 (permalink)
 
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Well, a matter of semantics I suppose. I also understand there is reality, and one reality is that very few pilots would have a level-off section in the EO missed profile...that is again, the worst case scenario...


The FAA is quite clear that the missed approach procedure is all engine, classifies EO as non-normal operations, and leaves engine out procedures to the operator.


There are many airports where there is a missed approach procedure, and EO is specifically not allowed...the aircraft must divert.

Balked operations are completely different....

Last edited by FlightPathOBN; 27th Dec 2012 at 17:23.
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Old 27th Dec 2012, 20:35   #23 (permalink)
 
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Quote:
During actual flight testing of engine out procedures, it was interesting to note just how difficult it is to make the climb and not violate the missed approach surface, especially if you are configured for landing, and near the 140kts CAT C speed....
5% at 140kts groundspeed is about 710ft/min. This might be a struggle in hot conditions high elevation and high weight.
2,5% is about 355ft/min at 140 kts.

Sorry but I really don't believe that most twins will struggle with 2,5% in reasonable conditions.

Offcourse as a performance engineer you will be presented with the difficult cases, probably the usual suspects. But on most airports I suggest that twins can easily handle 2,5% EO.
I haven't seen anything from our performance calculations LPC NG (A319/A320), that suggests otherwise.

And offcourse there are techniques to create a higher actual gradient: lower flap setting for landing (less drag in missed approach climb config) and a higher approach speed (more energy to start with)

Last edited by 737Jock; 27th Dec 2012 at 20:42.
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Old 27th Dec 2012, 21:09   #24 (permalink)
9.G
 
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737, the problem is that that 2,5% or whatever is required has to be maintained till MSA or MA level off altitude/level whichever comes first due to the fact that the level off segment has been deleted from the latest PANS OPS version. That puts a limitation on TOGA thrust usage even if the climb gradient is satisfied. So both criterion must be achieved GA climb gradient and duration of TOGA usage to be able to reach the necessary alt/lvl accelerate, clean up and ONLY then reduce thrust. That's where the performance dep. comes in and determines this threshold temp until which following the published GA is OK above which SE dep. must be followed. that's all at or above the mins below the mins (balked landing) the only choice left is to follow SE dep.

Last edited by 9.G; 27th Dec 2012 at 21:13.
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Old 27th Dec 2012, 21:57   #25 (permalink)
 
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737..

Well, that is also the case...most missed approach procedures are along the lines of straight ahead until 2500 or such...I would not get involved unless it didnt really really work, but the people loading up the ac will look at all of these factors for the destination airport anyways...
. As stated before, the criteria does not address EO missed, so one has to rely on 3rd party developers to sort out performance issues.
Think of the public missed...you have 737's out there with 20K engines, all the bleeds, MLW, and its 90 degrees out...then go EO....

My perspective is from RNP procedures, which must take into account the worst case setting for the aircraft, and typically the missed procedure for EO is the straight section, then the all engine missed has the turns...
That is why there are very specific procedures for different variants of the 737 family and many of those will not work with the A320 family.

Get calls all the time, especially from AUS, when the temperatures get high, and they dont want to limit weights...

The EO missed procedures with turns, if needed, would then result in an astronomical DA, temperature limits or weight limits.

Last edited by FlightPathOBN; 27th Dec 2012 at 22:00.
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Old 28th Dec 2012, 16:11   #26 (permalink)
LIN
 
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Italia458.
I think you have misunderstood something about PANS-OPS.
According to Doc 8168, you cannot choose to operate an aircraft in different CAT (reduced speed during circling in order to use lower minima, etc).
8168 Vol.II states: "An operator may impose a permanent, lower landing mass, and use this for determining V(at) if approved by the state of the operator. The category defined for a given aeroplane shall be a permanent value and thus independent of changing day-to-day operations." (Part I, Section 4, Chapter 1. 1.8.6)
and
"The design of procedures in accordance with PANS-OPS criteria assumes normal operations. It is the responsibility of the operator to provide contingency procedures for abnormal and emergency operations" (Foreword 1.5)
Hope this helps
Regards
LIN
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Old 28th Dec 2012, 16:57   #27 (permalink)
 
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LIN...

Quote:
According to Doc 8168, you cannot choose to operate an aircraft in different CAT (reduced speed during circling in order to use lower minima, etc).
I have that on my computer at home, I'll have to take a look at it. In Canada I'm not sure that 8168 is a specific document that we need to abide by. Being Canada, our rules are based on ICAO rules but we have the Canadian Aviation Regulations (official document) and the AIM which expands on the rules and provides some ways that you can comply with the CARs and then we also have the ICAO AIP.

I haven't seen a regulation specifically stating how the operating speed needs to be determined with regard to the specific Categories. If anyone can point me to something in a Canadian document that'd be great!
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Old 28th Dec 2012, 17:10   #28 (permalink)
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italia458, look at RAC 9.21
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Old 28th Dec 2012, 17:28   #29 (permalink)
 
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9.G...

RAC 9.21 states:

"Aircraft that are manoeuvred
within these category speed ranges are to use the appropriate
instrument approach minima for that category."

I'm well aware of that. It doesn't say that I can't operate 5 knots slower than 140 kts so that I can drop from Cat C to Cat B for departure so I don't need 2SM vis for departure!
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Old 28th Dec 2012, 17:36   #30 (permalink)
 
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Italia,

I have provided most of the RNP procedures used by Westjet in Canada...
NAVCANADA uses TP308 for the design critieria, which is virtually FAA TERPS.
The CAT references are the same as FAA... including the holding patterns.
Note that the FAA hold patterns are much different that the ICAO hold patterns. http://www.faa.gov/documentLibrary/m...er/7130.3A.pdf

(in answer to the CAT question, you can always fly a faster CAT than your aircraft, but never a slower CAT...)

TP308 references FAA documents for the following:
  • Non-precision instrument approach procedures;
  • Precision instrument approach procedures;
  • Departure instrument procedures; and
  • En route instrument procedures.

From TP308 ammendments...http://www.tc.gc.ca/media/documents/...s/ac2005-3.pdf

This amendment brings TP308/GPH209 up to date with FAA Order 8260.3B Terminal Instrument Procedures (TERPs) by incorporating new and revised sections based on TERPs changes 17-19.

From TP308 GPH209
Volume 6, Supplemental Criteria Construction
(1) Document 1 – Flight Management System (FMS) – Added
(a) Former US FAA Order 8260.40
(2) Document 2 – RNAV Departures – Added
(a) Former US FAA Order 8260.44
(3) Document 3 – Terminal Arrival Areas (TAA) – Added
(a) Former US FAA Order 8260.45
(4) Document 4 – Wide Area Augmentation System (WAAS) – Added
(a) Former US FAA Order 8260.50
(5) Document 5 – Required Navigation Performance (RNP) – Added
(a) Former US FAA Order 8260.51
(6) Document 6 – Precision ILS Category II/III (ILS CAT II/III) – Added
(a) Former US FAA Order 8260.61

Last edited by FlightPathOBN; 28th Dec 2012 at 17:46.
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Old 28th Dec 2012, 18:25   #31 (permalink)
 
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FlightPath...

I'm aware of TP 308 and of how it relates to other documents. The current document version is Change 5.3, not sure if you have that one.

Can you provide a reference for what you said: "you can always fly a faster CAT than your aircraft, but never a slower CAT"
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Old 28th Dec 2012, 19:05   #32 (permalink)
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Doc 8168.

1.3 CATEGORIES OF AIRCRAFT

1.3.1 Aircraft performance has a direct effect on the airspace and visibility required for the various manoeuvres associated with the conduct of instrument approach procedures. The most significant performance factor is aircraft speed.

1.3.2 These categories provides a standardized basis for relating aircraft manoeuvrability to specific instrument approach procedures. For precision approach procedures, the dimensions of the aircraft are also a factor for the calculation of the obstacle clearance height (OCH). For Category DL aircraft, an additional obstacle clearance altitude/height (OCA/H) is provided, when necessary, to take into account the specific dimensions of these aircraft.

1.3.3 The criterion taken into consideration for the classification of aeroplanes by categories is the indicated airspeed at threshold (Vat ), which is equal to the stall speed Vso multiplied by 1.3, or stall speed Vslg multiplied by 1.23 in the landing configuration at the maximum certificated landing mass. If both Vso and Vslg are available, the higher resulting Vat shall be applied.

1.3.4 The landing configuration that is to be taken into consideration shall be defined by the operator or by the aeroplane manufacturer.

1.3.5 Aircraft categories will be referred. to. throughout this document by their letter designations.

1.3.6 Permanent change of category (maximum landing mass).

An operator may impose a permanent lower landing mass, and use of this mass for determining Vat if approved by the State of the Operator. The category defined for a given aeroplane shall be a permanent value and thus independent of changing day-to-day operations.

1.3.7 As indicated in Tables I-4-1-1 and I-4-1-2, a specified range of handling speeds for each category of aircraft has been assumed for use in calculating airspace and obstacle clearance requirements for each procedure.

1.3.8 The instrument approach chart (IAC) will specify the individual categories of aircraft for which the procedure is approved. Normally, procedures will be designed to provide protected airspace and obstacle clearance for aircraft up to and including Category D. However, where airspace requirements are critical, procedures may be restricted to lower speed categories.

1.3.9 Alternatively, the procedure may specify a maximum IAS for a particular segment without reference to aircraft category. In any case, it is essential that pilots comply with the procedures and information depicted on instrument flight charts and the appropriate flight parameters shown in Tables I-4-1-1 and I-4-1-2 if the aircraft is to remain in the areas developed for obstacle clearance purposes.

Last edited by 9.G; 28th Dec 2012 at 19:06.
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Old 28th Dec 2012, 19:33   #33 (permalink)
 
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Here is an FAA reference...

SAFO 12005
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Old 28th Dec 2012, 20:49   #34 (permalink)
 
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9.G...

As stated in a previous comment I don't believe 8168 applies to Canada. Also, 8168 is talking about categories based on Vat which is essentially Vref - the speed to be targeted at 50' above the runway, over the threshold. That is NOT what Canada's rules are based on. Canada's rules for categories are based on your indicated speed at which you are commencing the maneuver at. I thought you knew that as you referenced a Canadian document; RAC 9.21. If you will do a circling approach at 140 kts you will be in cat C. Our Vref speed is in cat B - however we do NOT get to use the circling minima for cat B as we are operating in the speed range of cat C.

Again, I have not seen any rule in Canadian regulations that state we can't change indicated airspeeds while maneuvering to change the category we are in.

Last edited by italia458; 28th Dec 2012 at 21:01.
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Old 28th Dec 2012, 20:59   #35 (permalink)
 
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FlightPath...

I have never seen such a thing and I don't believe it exists in Canada. I've looked into this before as I used to teach multi-IFR and I'm quite sure Canada doesn't have those rules. It makes sense that the category doesn't change IF you base it on Vref for the MCLW. The way Canada does it is by the indicated speed at which you're operating for the particular maneuver.

I think there's a bit of a problem when you base it on Vref though, as you will be flying significantly faster than that while circling. The aircraft I fly, we circle in cat C, fly to the MAP on a precision or NPA in cat C but our Vref is cat B. The Canadian way seems more restrictive. It's entirely possible we could fly our approaches and circling 5 knots slower so that everything is in cat B though.
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Old 28th Dec 2012, 21:52   #36 (permalink)
 
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The CAT certification is by the aircraft manufacturer.

The 8168 final approach CAT is based on the speed of the SEGMENT, FAF to threshold, not crossing the threshold. There are other segment and holding speeds per the CAT.


You can go up a CAT by going faster, if conditions warrant and the regulator allows. Many CAT C aircraft, esp 737 variants, use a CAT D approach speed and minima, IF they are authorized...
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Old 28th Dec 2012, 22:10   #37 (permalink)
 
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FlightPath...

Interesting. But not in Canada. It seems like you're an approach designer - I would assume you understand why it would be good to limit an airplane based on the speed at which they're flying a maneuver or segment in instead of their Vref speed?

I am a little confused as to what you're talking about though since you just mentioned 8168 final approach CAT is based on the speed of the final approach segment but 8168 and your FAA document states that it's based on Vat (Vref).

What does the FAA use for determining category for specified visibility takeoffs?

Last edited by italia458; 28th Dec 2012 at 22:11.
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Old 28th Dec 2012, 23:52   #38 (permalink)
 
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The final segment CAT speed is based on Vref. So for a CAT C aircraft, speed in the final approach segment can range from 140 to 164 kts IAS.

Other segments have minimum speeds as well per CAT..


To calc RVR:
rho=log(I=ET ) 􀀀 2 log/RVR

MOR =log(0:05)RVRlog(I=ET ) 􀀀 2 logRVR equals 3RVRlog(I=ET ) 􀀀 2 logRVR

  • Calculate MOR550 corresponding to RVR = 550m using the intensity of the
    edge lights.
  •  Calculate MOR200 corresponding to RVR = 200m using the intensity of the
    centre line lights.
  •  Using Koschmeider’s Law, calculate the actual MOR.
  •  Compute such that MOR = MOR550 + (1 􀀀 )MOR200. Then the …nal
    value of RVR = 200 + 350 .

Last edited by FlightPathOBN; 28th Dec 2012 at 23:52.
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Old 29th Dec 2012, 00:13   #39 (permalink)
 
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FlightPath...

This is from Canada's current TP 308 document - there are 3 pages I've uploaded.

First page shows that all maneuvers are based on airplanes flying by the speeds listed under paragraph 212 - this is applicable all times there are specific restrictions or minima for categories published (ie: spec vis departure, DA, MDA, circling, etc.)

As you know, TAS at altitude will be higher than IAS and that needs to be compensated for. Formulas published in the TP 308 document account for that.

Page 3 shows a very similar chart to the one you posted. This is Canada's guide to developing instrument procedures and this is what we follow. Essentially, protection areas are defined based on these speeds, which provides a margin of safety for aircraft operation.

I will emphasize that aircrews are to abide by the chart on page 1 to determine what category they are in based on their indicated speed at which they are carrying out the maneuver.


https://www.box.com/s/iwreiuzbt040jglkwhra
https://www.box.com/s/3htnrh8n6kvw389n3zw7
https://www.box.com/s/2frpd9y2ipb12lqma4x2

Edit:

Quote:
What does the FAA use for determining category for specified visibility takeoffs?
I don't think you understood my question. A specified visibility takeoff is a visual climb over the airport for the initial departure, up to a specified altitude so as to clear obstacles. Usually a standard 1/2 departure will also be depicted but with a climb gradient in excess of 200'/NM. If you are unable to meet the required higher climb gradient, you have the option of departing while maintaining visual contact with the center of the aerodrome until a certain altitude that will permit a 200'/NM climb up to the minimum altitude for enroute operations. The required visibility in Canada for such a takeoff is: Cat A (1SM), B (1.5SM), C and D (2SM).

Does the US have such a thing?

Last edited by italia458; 29th Dec 2012 at 00:18.
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Old 29th Dec 2012, 15:18   #40 (permalink)
LIN
 
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Italia458:
I have to give in! You are correct in what you say, but only with regard to Canadian rules! The original question was with regard to Doc 8168, however.
I have just had a short look at TP 308, and I must say that I'm amazed at how much different from DOC 8168 it is. Even basic things like primary and secondary areas are very different, Speeds for categories of aircraft are completely different, etc, etc.
How on earth there can be that great differences in criteria from country to country within the very international world of aviation is beyond me.
I am a PANS-OPS designer, so I do know 8168, but I will certainly not call myself an expert on TP 308 (or TERPS, for that matter).
Why can't we all agree on using one set of rules? Isn't that why we have ICAO?
Regards
LIN
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