Rod Machado s Instrument Pilot s Handbook

Transcription

1 11-10 A fix from which to measure the allowable limits of travel for the procedure turn. the procedure turn must remain (NORCO in our example). This limit is normally 10 nautical miles. For now, let s agree that this will work for our VOR approach to Runway 9 at Riverside. Of course, this distance limit means nothing if you aren t aware of it. Fortunately, the let s hide the procedure turn distance from the pilot gag is no longer a favorite pastime of TERPs specialists. That s why this information is usually found in the chart s profile view (Figure 15). Since NORCO is the place where the procedure turn officially begins, we ll also label it as the initial approach fix or IAF (IAFs are always labeled on approach charts with the letters IAF in parentheses). In case you re wondering why you need to identify an initial approach fix, think back to the FAR section that discussed lost communications procedures. Recall that you are required, under certain circumstances, to proceed to the fix from which an approach begins (page 8-34). The IAF is this place, and there are often several IAFs shown on approach charts. Before we can decide on the minimum altitudes for the procedure turn, we need to assess the terrain for height and obstructions. You don t want your procedure turn to place you at the same altitude used by dirt bikes, do you? We want to be practical about this. We don t want nor do we need to have the procedure turn done at Procedure Turn Distance Limits Fig. 14 says, Are we there yet? At the point of no return? Because of your enviable brain power, you re probably thinking that a pilot might get in trouble if he just kept flying outbound on that 277 degree radial and began his procedure turn a hundred miles from the VOR. You re right (proving once again that Ginko biloba actually works). That s why procedure turns always come with distance and speed (200 knots IAS) limitations in reference to a specific point on the approach structure. Anything beyond is no man s land; go there and no man is guaranteed to land. Flying a procedure turn at the speed of sound would surely result in a sound the sound of an airplane boring into the side of a mountain somewhere. It might be boring for the airplane, but certainly not for the pilot, to whom it would be totally terrifying. So let s establish that far-out point by creating an intersection on the approach course. There are several ways we can do this, but the simplest is to find a nearby VOR and use a cross radial. It happens that Paradise is nearby (I mean the Paradise VOR), so let s use its 355 degree radial and a very thin black line to establish an intersection that we ll call NORCO, as shown in Figure 14. Procedure Turn Limitations A TERPs specialist will look at the nearby terrain and establish a limit from a specific fix or point within which Profile View Fig. 15

2 Chapter 11 - Understanding Approach Charts Holding Patterns in Lieu of a Procedure Turn OK, the barb-type procedure turn is a very popular means of course reversal, but it s not the only way to get the job done. And that s good, because it s not always possible for a TERPs specialist to use it at a given airport. One reason is that this procedure requires a great deal of space. The oval area used by these course reversals can make them impractical. Any higher terrain that intrudes can require an unreasonably high procedure turn altitude. This, in turn, increases the required rate of descent on final, which has definite limits under the TERPs standards. Enter the holding pattern used in lieu of a procedure turn. The holding pattern shown to the right is an excellent means of course reversal because it uses much less space to get pilots reversed and on course. Given that instrument pilots know how to enter a holding pattern, they can easily cross the fix from which the holding pattern begins, enter the pattern via one of the three methods described in Chapter 6, reverse course and be set up to fly the approach course inbound. The one major difference about the holding pattern versus the barb-type procedure turn is that the holding pattern must be flown exactly as shown on the chart. Freelance efforts to create your own holding pattern will not be applauded by ATC. If you need to express yourself creatively, take up ceramics after you land. While you can technically do any type of course reversal when the is used (i.e., you could do a degree turn if it brings you great pleasure), you must fly the holding pattern as given, such as using one minute legs as shown above. On the other hand, everything else we ll discuss about procedure turns still applies to the holding pattern. As a side note, in Chapter 12, you ll learn that the barb-type procedure turns aren t used in GPS approaches. The primary area in which the procedure turn is conducted provides 1,000 feet of terrain and obstruction clearance. The secondary area provides 500 feet of the same. Fig. 16 an altitude that keeps us above all obstructions south to the Mexican town of Hasta la Vista Bebe. We only need an altitude that keeps us safe at a reasonable distance, while turning, based on the maximum procedure turn speed of 200 knots IAS. So what geometric area would be reasonable within which to provide terrain and obstruction clearance? TERPs specialist use a modified geometric race-track like pattern consisting of primary and secondary areas of protection to make this assessment. While we won t cover this in great detail here (read Chapter 14 of Rod Machado s Instrument Pilot s Survival Manual for more detail on these and other charting issues), you can get an idea of how this plays out in Figure 16. The procedure turn area must provide the pilot a minimum of 1,000 feet of terrain and obstruction clearance within the primary area and 500 feet within the secondary area (the secondary area tapers to zero protection at the border). Perhaps the most important take-away idea from this figure is to always make sure you do your procedure turn on the proper side of the approach course (the maneuvering side where the barb is). Even if you re a TV evangelist with a terrain-specialized guardian angel, you don t want to do your procedure turn on the wrong side of the approach course. First, your reinforced hair won t protect you in a collision of this magnitude. Second, for all you know, nobody has even considered that side. Could be dragons there. Consider it marked Abandon ye all hope who enter here. Dante go there.

3 11-12 Looking at Figure 17 (and using other topological charts that I haven t shown), a TERPs specialist would probably find that there are no obstacles standing at an altitude greater than 2,000 feet along the westwardextending approach course (which is officially referred to as the approach procedure track) for the anticipated distance of the procedure turn. Therefore, the charting specialist would add 1,000 feet onto the terrain and obstruction clearance height of 2,000 feet and make this value 3,000 feet, the minimum altitude for the procedure turn. The Approach Procedure Track to Rwy 9 at Riverside Fig. 17 B A The profile view below shows the minimum altitude for the procedure turn (3,000 feet MSL) and the minimum altitude at which to track the approach course inbound (2,100 feet MSL). Fig. 18 Figure 18 shows the chart s profile view indicating a minimum of 3,000 feet for the procedure turn. The line under 3,000 feet means that this is a minimum altitude. You can remain higher if you like, but you can t go any lower (not even if you have a TV evangelist hair helmet). Once you ve completed the course reversal and are established inbound to the VOR on the approach course, you can descend to a minimum altitude of 2,100 feet (where the TERPs specialist has determined there are lower obstacles along this route) if you wish, as shown in the profile view. Take a second to look at the symbology in the profile view. The thick, downward, right-to-left sloping line leading outbound from NORCO (Figure 18, position A) signifies the procedure turn and its minimum altitude of 3,000 feet. The approach course line (downward, left-to-right sloping) leading inbound to NORCO (Figure 18, position B) signifies completion of the procedure turn (when you re established on the 277 degree radial inbound to RAL VOR), thus allowing a lower altitude of 2,100 feet prior to reaching NORCO intersection. Now, I hope you like to get down, too. This doesn t mean dancing. It s almost always wise to descend to the lowest altitude permissible on any given portion of an instrument approach. First, because you don t want to have to make a last-minute plunge for the asphalt (or concrete). Second, because the closer you get to the runway vertically, the better chance you have of seeing the asphalt or concrete and being in a position where you can safely descend and land on it. That

4 Chapter 11 - Understanding Approach Charts is the objective, isn t it? You don t want to fly an instrument approach and not land because you didn t get low enough. Imagine saying to your passengers, The four planes ahead of us landed, but they were 2000 feet lower, which might be why they could see the airport. I just didn t want to get down today. Feeder Routes There s one little problem we need to address before continuing to draw our chart. What is the minimum altitude a pilot should fly from Riverside VOR to NORCO intersection? This isn t covered in our profile view, right? Figure 19 provides the answer. A TERPs specialist will evaluate the local terrain and decide on a safe altitude for the route from Riverside VOR to NORCO via the Riverside VOR 277 degree radial. Then he ll create something known as a feeder route, to make the transition clear to the pilot. Think of a feeder route as feeding you onto the initial approach structure via the IAF. Feeder routes Feeder Route A feeder route from the RAL VOR to NORCO intersection is shown as a charting offset. This route indicates a minimum altitude of 4,000 feet MSL, a distance of 3.7 miles and a direction of 277 degrees. Fig. 19 PETTIS NDB is a local navaid from which a feeder route might be constructed allowing pilot self-navigation onto the approach structure. always contain the altitude, direction and distance necessary to make a transition from one point to the next on a chart. These routes are typically identified by a medium thick black line and have altitude, direction and distance information listed nearby. In Figure 19, the feeder route from the Riverside VOR is offset slightly (known as a charting offset to make it clear what you re supposed to do here) from the main approach course and indicates a minimum altitude of 4,000 feet and a direction of 277 degrees for 3.7 nautical miles to NORCO intersection (distances on feeder routes are placed in parenthesis to prevent confusion with altitude values, just as I ve placed this sentence in parentheses to identify it as a separate but important thought). Now that we ve created the basic instrument approach structure, we should consider an additional and alternative method of getting onto the approach course at Riverside. Said another way, we need to build more feeder routes so we can transition from other navaids, intersections and airways onto our approach course at Riverside. We ve already created a procedure turn, which allows us a means of course reversal in case you arrive at Riverside VOR from a direction other than that of the inbound approach course. For instance, what would happen if you are on a nearby airway or at a nearby navaid and want to transition onto the approach? Let s find out. The nearest NDB is named PETIS (Figure 20). It would be nice if we could have a transition from this NDB to the approach structure. After all, it s in the best interests of all Navaids That Help Create Feeder Routes Fig. 20

5 11-14 instrument pilots to have as many feeder route transitions on the chart as possible. Remember, the assumption is always that you will have to do your own navigation, with no choice for getting from enroute to approach other than via feeder routes (look ma, no radar!). Does the radar really stop working on occasion? You bet it does. Nothing s foolproof. Someone could spill their mocha milk-a grande supremo coffee on the circuitry, causing circuitry seizure in a puff of mocha milka java smoka (it would take a skilled electrician who uses Maxwell s equations to fix it, too). On one occasion in Southern California, the local TRA- CON was nearly evacuated because of an approaching wildfire. It was out of the fire for the controllers, and into the frying pan for the pilots. In situations like that, pilots would be given instructions to fly certain transitions onto the approach structure, then cleared to fly the instrument approach, all without the aid of a radar controller. Yes, boys and girls, once upon a time it was all done that way. You could, for example, be instructed to proceed to the Riverside VOR at 5,000 feet, and then be cleared for the VOR Runway 9 approach to Riverside. Given this clearance, as far as the controller is concerned you ll fly to the Riverside VOR at 5,000 feet, then track outbound on the 277 degree radial and descend to 4,000 feet, descend to 3,000 feet once past NORCO, fly the procedure turn, and once established inbound on the 097 degree course to Riverside, descend to 2,100 feet and complete the approach. The system works without radar because controllers can keep airplanes separated by the use of pilot position reports, as they did in the early days of aviation (and I don t mean last Tuesday, either). By reviewing local terrain information and the availability of nearby navaids, a TERPs specialist can construct several feeder routes to help pilots transition onto the approach course. One example is the feeder route from PETIS, shown in Figure 21. It looks like a bearing of 200 degrees and a minimum altitude of 5,000 feet for 7.5 nautical miles will work, given the local obstructions and terrain. Since the transition begins at the NDB, it is flown by ADF bearing to the Riverside VOR and not a radial or course to the VOR. You just have to use a little common sense to figure this out. It s possible and even likely that if you were in the vicinity of PETIS NDB, the controller would request that you proceed direct to the NDB, and then clear you for the VOR Runway 9 approach to Riverside. If that happened, you d fly direct to PETIS, track the 200 degree bearing to Riverside VOR and descend to 5,000 feet, turn and track outbound on the 277 radial from Riverside VOR and descend to 4,000 feet until reaching NORCO, then descend to 3,000 feet, fly the procedure turn and then, once established inbound on the approach course, you d descend to 2,100 feet and fly the approach (more on this last part later). And you d do it all on your own, without having the controller there to give you radar vectors onto the approach course. It s important to remember that only medium thick lines (i.e., feeder routes) and maximum thick lines (initial approach segments and approach procedure tracks) have altitudes and distances associated with them. This means you can fly these routes on your own using your own navigation. Said another way, a route shown on the approach chart isn t flyable using your own navigation if that route is associated with only a very thin line (a thin line, one that is.007 inch thick, is typically used to identify an intersection or show a VOR radial/course). For example, given the completeness of our chart at this time, the 355 degree radial from Paradise VOR (thin line, Figure 21) isn t flyable because it doesn t have medium or maximum thickness. More important, it doesn t have an altitude, direction, and distance associated with it. That s because the Paradise VOR 355 degree radial forms NORCO intersection. Just think of the medium (.01 inch thick) and maximum (.02 inch) thick lines as advertising signs. They provide you with information. They say you can fly these routes using your own navigation. It s kind of like a sign outside Bubba Bob s restaurant that says, Eat at Bubba s. 5,000 flies can t be wrong. That tells you something. It says don t eat there unless you ve had a tetanus shot. Feed Me More Feeder Routes Since we re constructing feeder routes, we should, however, try to establish one from the Paradise VOR onto the approach structure via NORCO intersection. After all, the Paradise VOR is a major VOR in the Los Angeles basin (pilots love saying they ve flown over Paradise) and it has several major airways passing through it, as shown in Figure 22. By examining local terrain and obstructions, a TERPs specialist will create a feeder route using the 355 radial from Paradise and having a minimum altitude of 3,200 for a distance of 3.5 nautical miles, as shown in Figure 23. Because this is now a flyable route, it gets its own medium thick line with an arrow. About all it lacks is a merit badge. Or, if it misbehaves, a demerit badge. Of course, bright student that you are, you may be wondering why we didn t create a route from the Paradise VOR to the Riverside VOR, instead of creating a route that goes to NORCO intersection. After all, there s already a feeder route that starts at the Riverside VOR. Wouldn t it just be better to go from PDZ VOR to Riverside VOR and fly the depicted feeder route outbound? Not necessarily. First, it s always better to have feeder routes onto the approach structure begin at major intersections or navaids on the chart. This provides a pilot with more choices, makes his and everyone else s job easier, makes the world a happier place, causes flowers to bloom better, and birds to sing louder. In other words, isn t it better to have 10 freeway onramps in a big city instead of just one? The second reason is that TERPs specialists design transitions to the approach structure so that pilots don t turn more than 120 degrees to become established on the connecting segment (in fact, 120 degrees is the maximum allowable limit for turns made when transitioning from one electronically navigated route to another). Heading from PDZ to Riverside VOR, then tracking outbound on the approach course requires a turn of approximately 130 degrees. It s just a lot cleaner and simpler to establish the PDZ transition directly to NORCO intersection.

6 Chapter 11 - Understanding Approach Charts Feeder Route A feeder route from PETIS NDB allows a pilot to fly to RAL VOR at a minimum altitude of 5,000 feet MSL on the 200 degree bearing for a distance of 7.5 nm. Feeder Route A feeder route from PDZ VOR allows a pilot to fly to NORCO intersection at a minimum altitude of 3,200 feet MSL on the 355 degree radial for a distance of 3.5 nm. Fig. 21 Fig. 23 Paradise VOR The Paradise VOR has many airways that run through it. As a result, this VOR can provide several feeder route transitions for the many airports having instrument approaches in the Southern California area. Fig. 22

7 11-16 The Five Segments of an Instrument Approach Instrument approaches consist of five parts or segments, each with its own symbols, rules, customs and quirks. The five segments are the feeder route, initial approach segment, intermediate approach segment, final approach segment and missed approach segment, as shown in the figure on the right. Each segment is designed to allow you to safely and comfortably accomplish the specific objective of approaching an airport in IFR conditions. In much the same way that a staircase allows descent one step at a time, instrument approaches lower you in an orderly and progressive fashion. In aviation, it s a five-step program. If you understand the specific purpose of each instrument approach procedure segment, you will better understand how to execute the procedure. The basic idea of all the segments making up an instrument approach is to take you from wide, expansive airways that are miles in width to fine, precision-like navigational tunnels. Vertical and horizontal tolerances, speeds, and margins of safety all become smaller and more critical as you approach the runway. The various segments are designed with this in mind. They take you from the lofty-above and return you back to the surly bonds of earth. And they do it step by step, with forgiveness for excursions growing ever more stingy. As you get close to the runway, you lack slack. Approach segments are flown in a specific sequence, as shown in the figure above. Size may not matter, but order definitely does. Starting with the feeder route, the aircraft is taken to an initial approach fix (IAF). IAFs are usually identified on the plan view of the approach chart. Initial approach segments start at the initial approach fix (IAF), and proceed to the intermediate fix (IF). IAFs are labeled with the letters (IAF), intermediate fixes are labeled with the letters (IF) on U.S. approach charts. The intermediate segment takes you to the final approach fix (FAF). While the initial approach segment may give you 1,000 feet of terrain and obstruction clearance, obstacle clearance may be as low as 500 feet on the intermediate segment. I told you tolerances would get tight. When the final approach fix (FAF) exists, it is identified by a Maltese cross in the profile view of the chart. This is the place where your final descent to the lowest minimum altitude permissible on the approach begins. When the missed approach point (MAP) is reached, if you can t meet the legal landing criteria then the missed approach segment takes you to the missed approach holding point. According to Figure 23, we now have three feeder routes shown on the chart s plan view. One begins at Paradise VOR, the other at Riverside VOR and the last at PETIS NDB. Each leads you to a point where you can intercept the approach course outbound (the Riverside 277 degree radial) and fly the procedure turn before proceeding inbound. In Catholic school, a nun once asked me to use ominous in a sentence. I stood up and said, Ominous guy. Later, in the emergency room, as I regained consciousness, I understood what ominous really meant. While it might not be ominous if an approach chart didn t have additional feeder routes to help you transition from the enroute to the approach structure, it would certainly be a shame. So let s do what TERPs specialists do and build additional feeder routes onto the approach structure, where possible. Before we can do this, we need to solve the problem of charting scale. How Terrain and Obstructions are Depicted on the Plan View The relief features associated with terrain on the approach chart s plan view are depicted when that terrain exceeds 4,000 feet above the airport elevation. Terrain may also be depicted if, within six nautical miles of the airport reference point (ARP), the terrain rises to 2,000 feet or more above the airport. Terrain meeting these criteria is shown because it should be of interest to the pilot (especially if that pilot s airplane doesn t have a force field). Normally, terrain will be depicted by five or less tints of brown, with consecutively darker tints representing higher terrain elevation contours. Contour levels of 1,000 feet are used in this presentation. Terrain more than 4,000 feet above the airport elevation. Terrain more than 2,000 feet higher than the airport elevation lying within six miles of the airport.