Hot answers tagged

32

From FAA INFO 15002: A [snowflake] -XX°C icon will be incrementally added to airport approach plates, beginning Mar 5, 2015. The icon indicates a cold temperature altitude correction will be required on an approach when the reported temperature is, “at or below” the temperature specified for that airport. This looks to be a work-in-progress, as they ...


14

DME is "Distance Measuring Equipment". It tells you how far you are from the equipment transmitting the signal. This is often co-located with a VOR, or at an airport. turn heading 180 degrees to LGA 2.5 DME So, this means turn due south and continue until you are 2.5 nautical miles from LGA. At this point you're instructed to turn left on to a heading of ...


12

The key is in the part of the procedure description I've highlighted: When local altimeter setting not received use Northeast Philadelphia altimeter setting -- you're using the altimeter setting for an airport 15 miles away. 15 miles may not seem like a lot of distance, but it's enough for there to be a notceable variation in altimeter settings. The FAA ...


11

It indicates a "temperature restricted" airport where precautions are required to calculate and set correct altimeter settings because the errors caused when the temperature is at the lowest recorded , if not corrected, can exceed the required obstacle clearance shown on the chart. Since the air is significantly more dense than the "ISA standard day", the ...


8

Original answer: The speed of Category A aircraft is too low to execute the missed approach. For this particular airport, it's basically a hole in the ground with steep mountains on all sides. To go missed, you gotta get up in a hurry, and the TERPS data probably indicates a minimum speed is needed. Edit: Despite the downvotes and comments stating that ...


8

While researching this subject, I found a few things that shed light on the subject: Procedures FAA ATC Order 4-8-1 Note 1 says: 1. Clearances authorizing instrument approaches are issued on the basis that, if visual contact with the ground is made before the approach is completed, the entire approach procedure will be followed unless the pilot ...


7

As best I can understand from the TERPS, it's because there are certain criteria for RNAV missed approaches that wouldn't be met by copying the ILS missed approach. Specifically, I found the following (see chapters 7 and 15): In RNAV missed approaches "turns shall not exceed 120°", but the ILS missed approach requires about a 180° turn. There's some ...


7

Section 5-4-9 of the AIM contains a lot of guidance on procedure turns, and says (in short): If the procedure turn is charted as a teardrop or hold-in-lieu of procedure turn, then it must be flown as charted. (Does not apply in this case.) If it is a standard procedure turn, the barbed arrow shows the maneuvering side (so the first turn should be flown as ...


6

Closest regulatory thing I could find : ICAO Doc 8168 Section 4 Arrival and approach procedures 1.7.5 Any constant descent angle shall clear all stepdown fix minimum crossing altitudes within any segment. 5.2.5.1 A stepdown fix may be incorporated in some non-precision approach procedures 5.5.5.2 The protection area assumes that the ...


5

There are two situations to consider: altitude restrictions before the Final Approach Segment altitude restrictions in the Final Approach Segment The first case is clear-cut. There is a risk of going outside altitude restrictions if you intercept the glideslope before the published glide slope intercept point, except if noted otherwise. An FAA Information ...


5

The STC documentation provided with the GPS / FMS installation will indicate the type of minima it can go down to. Typically, GA aircraft like a Garmin 430/530 will only be certified down to LNAV minima. Business type aircraft with FMS's may be certified to LNAV/VNAV minima. These installations use a barometric altitude input to calculate a pseudo ...


4

You are confusing some terminology. RNAV (GPS) approaches can have several different sets of minima. See the example RNAV (GPS) Y 28L at O'Hare: It has: LPV LNAV/VNAV LNAV sets of minima. LPV is an instrument approach procedure (IAP) with localizer-type precision and with vertical guidance, (hence the name LPV), provides a pilot with a "ILS-style" ...


4

"a barbed arrow indicates the maneuvering side of the outbound course on which the procedure turn is made" That only means the procedure must be flown on the east side of the outbound course. It does not tell you which way to turn after flying 039 degrees. JEPP charts show the entire loop on a procedure turn and they never turn towards the FAF. The turn ...


4

In the FAR's it is left up to the pilot how to perform the turn. You just have to do it on the correct side of the approach coarse and stay within the protected area. In your instrument training, your instructor may have insisted that you fly a standard barbed PT just as it's depicted. Nothing wrong with that. But you don't have to do it that way. Both ...


4

At the very beginning of my answer, I would like to remind that everyone should be familiar with the type of charts he is using. A thorough description (PDF) of all charts published by the FAA is available on this FAA website. Refer to page 77 of the PDF document to find the altitudes your question is dealing with. On every flight, you make decisions based ...


2

Well, some of the things you are talking about are not even permitted for a visual approach :-) Here's my 2c : ICAO Doc 8161 7.2.2 After initial visual contact, the basic assumption is that the runway environment should be kept in sight while at minimum descent altitude/height (MDA/H) for circling The circling approach allows you to fly at/below ...


2

This is speculation, but in the absence of an obvious technical reason it's at least possible that this is because category C/D pilots have better lobbyists than category A/B ones. I found an interesting but somewhat dated (1995) document called Establishing Visibility Minimums; the author used to chair the ALPA TERPS committee. It says: [The TERPS ...


2

I can't yet find where this is indicated in TERPS, but it appears that the OCS surface starts at the point before the threshold where the GP is 250 feet above the threshold height. I'm inferring that from this document about calculating VNAV criteria. It has the above diagram and says: The distance from the runway threshold where the OCS surface starts ...


2

Probably because it's so shallow: you have 8+ NM to descend about 1100'. On a 3 degree angle, you'd typically decsend 1100' in a little over 3 miles. I'll leave it to good folks with calculators to work out exactly what angle this would be, but it's under 1.5 degrees, so probably below whatever limit TERPS gives for depicting an angle there. One solution ...


2

RNAV(GPS) procedures being combined with LPV or LNAV/VNAV, which are Landing Systems Your confusion here is that LPV is a landing system which it is not. It is a way of saying your GPS is going to work kind of like an ILS and will have similar horizontal/vertical responses on your way down or as the FAA puts it Localizer Performance with Vertical ...


2

I will have to answer my own question, since I have noticed that in FAA's PBN Manual it states: PBN 8260.58A 1-2-5c . Turn parameters. For OEA construction, a turn is indicated when the course change exceeds the alignment tolerance of 0.03 degrees. So, at least as far as route design is concerned, the alignment threshold for turn indication is 0.03 ...


1

I think what you're talking about are what pilots refer to as "fly-past" and "fly-over" waypoints. Up until recently, all waypoints in the world were "fly-past", ie you could cut the corner from one leg to the next and not actually fly over the waypoint itself. This is still the standard, unless otherwise stated. But then some SIDs and STARs needed people to ...


1

Because the navigational beacons and the indicator instruments in the cockpit are such that the system is less precise at longer distances. Second the plane must find the initial fix or intersection while flying blind under IMC before becoming aligned and so the area acts like a funnel. In some areas the terrain may limit the radio beacon signal so a wedge ...


1

The probable reason why the obstacle clearance surface line is shown terminating prior to the threshold is because the glide slope transmitter antennas are located about 50 feet in front of the threshold. When a plane lands using instruments, it uses what is called the "instrument landing system" (ILS), and nearly all commercial airports have them. The ILS ...


1

The minima's are usually decided based on the Missed Approach procedure, which one of the criteria being obstacle clearance. I believe the answer lies in your question, its due to the heading course and altitude restriction on the MAP point. RWY 16L needs to climb straight 165 deg which puts you through the obstacle , whereas 16R Missed approach procedure ...


1

Look at the top left of the profile view, you see "Remain within 10nm" you can do the turn however you want as long as you remain with in 10nm. A 172 may have no problem staying inside 10nm if they did the turn to the left, a HondaJet might have more trouble remaining within the protected airspace.


1

GPS approaches and missed approach routing are designed point to point to point, so "climb to XXX then direct ABC" doesn't work -- there is no defined track to sequence to after the straight-ahead leg. So the GPS approaches can't use the same procudure as the ILS does. There does seem to be a terrain or obstacle issue somewhere on the missed approach ...


1

Look at where the missed approach points are on each approach. The ILS has you very low, and possibly unable to clear the terrain to the northeast, hence the turning procedure. The RNAV has you going missed almost 1000 feet above the ILS, so terrain clearance would not be as much of a factor. For either ATC or convenience reasons they probably prefer you to ...


1

Think of it this way ... Before the published glideslope interception point (lightning bolt symbol) we must respect all published crossing altitudes even in receiving a glideslope signal. Once inside the published glideslope interception point the glideslope becomes the primary vertical navigation. Published altitudes inside the glideslope intercept point ...


1

The asterisk informs the pilot that this only applies to the Non-Precision LOC approach. The bolded V is indicating this is a Visual Decision Point (VPD). See Aeronatical Charts Users Guide. On some IAPs the decent rate required to reach the minimum decent altitude (MDA) by the missed approach point (MAP) at a distance from the threshold that will allow ...


Only top voted, non community-wiki answers of a minimum length are eligible