TAAs for TAAs by Matt McDaniel In the past few years the aviation industry and the FAA have coined a new term Technically Ad vanced Aircraft (TAA). Most pilots envision a TAA to be one of the several new composite, glass cockpit, fully automated aircraft that have flooded general aviation ramps in the last decade. However, the reality is much simpler. The FAA s definition for TAA is an aircraft equipped with at least one IFR approach certi fied GPS (with a moving map) and a coupled autopilot. By that description, the majority of King Airs flying would qualify as TAAs (either as they were manufactured or as they have been modified or upgraded). Now that you King Air operators are all puffed up with pride at your new-found status, you d probably like to go fly one of those fancy GPS approaches. Chances are very good that approach will incorporate the other TAA the Terminal Arrival Area. While your aircraft doesn t have to be of the TAA variety to be equipped to shoot approaches incorporating TAAs, the two do typically go hand-in-hand. It is the latter TAA (Terminal Arrival Area) that we will discuss here. Not only is it a fairly recent addition to the IFR vocabulary, it is chock full of misunderstanding. A simple lack of knowledge about this new and improved method of transitioning from the en route structure to the terminal environment (approach phase) is the primary source of such confusion. The TAA is covered well in Chapter 5 of the Aeronautical Information Manual (AIM) and that should be your primary source of updated information on how to interpret and use it safely and legally. The first item to note is that TAAs will only be associated with RNAV (GPS) type approaches which, of course, are only going to be flown by aircraft equipped with approach-certified FMS or GPS navigation systems. However, TAAs are not found on every RNAV procedure (most often, they are absent in areas of heavy air traffic congestion). Yet, they are found extensively throughout the United States and where they are published, they replace the charted Minimum Safe Altitude (MSA) for that particular approach procedure. By now, most of us are familiar with the T- con figuration RNAV approach procedures (see Figure 1, where a standard T is used, as well as a standard MSA circle). The T design (or slight variations thereof) provides efficient means of beginning these procedures by incorporating up to three Initial Approach Fixes (IAFs) and eliminating procedure turns (NoPT) for the outer two IAFs. The center IAF also serves as an Intermediate Fix (IF) when the approach is begun at either of the outer two IAFs and is, thus, generally labeled IF/IAF. Under certain 12 KING AIR MAGAZINE JANUARY/FEBRUARY 2010
circumstances, a holding pattern in lieu of a procedure turn may be required for proper course intercept and/ or altitude adjustment if the IF/IAF is indeed used as the IAF. Variations on this T design may cause the procedure to resemble a Y (where the outer legs are not perpendicular to the inbound course), an L (where one of the outer legs is missing, such as is often the case where parallel runways exist), or even an I when no outer legs are incorporated due to terrain, airspace or other elements restricting the procedure s design. Further variations can occur on any of the above examples, as well (see Figure 2, where the procedure resembles a lopsided Y and no TAAs are incorporated to replace the MSA). In spite of the two examples we ve seen so far, the majority of RNAV approaches now incorporate Terminal Arrival Areas and many previously designed RNAV approaches are being converted from the MSA system to the TAA system. Standard TAAs consist of three areas defined by the initial and intermediate approach segments. While the AIM defines these areas as the straight-in, right-base and left-base areas, it may be easier to think of them simply in conjunction with the IAF they are associated with (as depicted in the plan-view of the approach plate). The straight-in area (which feeds your flight directly to the IF/IAF and generally encompasses a 180-degree arc centered on the IF/IAF), can be further divided into pie slices defined by magnetic courses TO the IF/IAF. Minimum altitudes within each TAA sector are defined by distance arcs and each may contain multiple minimum altitude sectors (a.k.a. step-down sectors ). These minimum altitudes conform to standard obstruction clearance limits (1,000 feet or more where terrain dictates). Standard TAAs begin 30nm from the charted IAF. Since they replace the MSA circle that we ve always seen on approach charts, it should be noted that the standard MSA circle is a 25nm radius from a defined fix (often, but not always, the Final Approach Fix [FAF]). The standard TAA sectors incorporate significantly more real estate because they have a 30nm radius measured from up to three separate IAFs (see Figure 3, which contains standard 30nm radius TAAs with multiple distances, bearing sectors and minimum altitudes). Since TAA sectors are based upon the underlying RNAV approach, their shapes may be modified from the norm in order to conform with any modification that might exist to the standard T configuration of Figure 1: An example of standard T-configuration RNAV approach procedures, as well as a standard MSA circle. Figure 2: The procedure resembles a lopsided Y and no TAAs are incorporated to replace the MSA. JANUARY/FEBRUARY 2010 KING AIR MAGAZINE 13
the underlying approach. In fact, some TAA sectors could be eliminated altogether if terrain, the underlying approach, or other factors dictate. The FAA is no longer allowing the production of TAAs with missing sectors, but previously published ones still exist. Where am I? Inbound pilots should determine their position from the TAA boundary prior to arriving there. If you are currently navigating to the IAF that your sector is based on, both bearing TO and distance FROM the fix should be available to you at all times via the FMS or GPS. If the sector s outer boundary is 30nm and your distance from the fix is 40nm, you are 10nm from the TAA boundary. High level math, this is not! Pilots not currently navigating to a specific IAF, should determine which TAA sector they can expect to enter. This can be done by selecting the IF/IAF and determining the magnetic bearing TO it. Even if you are not planning on using the central IF/IAF as your specific IAF, it is the only one that will give a true indication of which sector you will enter from your present position, especially when approaching from near the boundary between the left and right base areas. Remember, each sector may have differing terrain and minimum altitudes, so knowing your position can be vital to safety of flight. Once you determine which TAA sector you will enter, you can request a clearance to the appropriate IAF as far out as you like to expedite your arrival. A Workload-Reducer or a Confusion-Producer? One of the primary purposes of the TAA is to expedite arrivals through efficient air navigation and via reduced interaction between the pilot and Air Traffic Control (ATC). If both pilot and controller are familiar and comfortable with the TAA rules, it can be a blissfully simple exercise for both to get the inbound aircraft from the en route segment to the runway. But, if either is even slightly out of sync with the rules or the thought processes of the other, confusion, unsafe assumption and increased radio chatter are likely to result. If the inbound pilot has been cleared to the IAF, they are expected to both proceed direct to that fix and to descend to the initial TAA minimum altitude upon entering the TAA. However, they may not descend further (such as might be assumed if the minimum altitude is lower at some distance further inside the TAA), without either specific clearance from ATC or being cleared for the approach. If cleared for the Retrofit. Rebuild. Renew. GARMIN G1000 UPGRADES RAISBECK MODIFICATIONS BLACKHAWK MODIFICATIONS CUSTOM PAINT AND INTERIOR The King Air Specialists (352) 796-5173 w w w. a m e r i c a n a v i a t i o n. c o m 14 KING AIR MAGAZINE JANUARY/FEBRUARY 2010
approach, the pilot is not only permitted, but is expected to descend to the minimum altitude depicted, upon entering the TAA and upon crossing into subsequent sectors of the TAA. Upon reaching the IAF, that same pilot would, of course, be expected to descend per the approach procedure. However, bear in mind, that a clearance to the IAF is not a clearance for the approach. To use a specific example, let s refer again to Figure 3. Let s assume you are approaching NIRYO on a bearing of 090 degrees TO (you are directly west of NIRYO) from 40 miles out. Several scenarios could certainly play out, but let s address three common ones to clarify the paragraph above. Scenario 1: From your position of 40nm west of NIRYO at 10,000 feet MSL, ATC states, King Air 12345, proceed direct NIRYO, expect the RNAV/GPS Runway 32 approach at Rapid City. You would, of course, navigate directly to NIRYO. You would also be expected to initiate descent to 9,400 feet upon crossing 30nm from NIRYO. Yet, you would not be expected (or authorized) to descend further (such as to 6,200 feet at 12nm from NIRYO) without either specific clearance to do so from ATC, or subsequently being cleared for the approach. Figure 3: Contains standard 30nm radius TAAs with multiple distances, bearing sectors and minimum altitudes. 16 KING AIR MAGAZINE JANUARY/FEBRUARY 2010
Scenario 2: This time, we ll assume we are proceeding to NIRYO as per scenario 1, currently 25nm from NIRYO. ATC then states, King Air 12345, descend and maintain 8,500 feet, cleared for the RNAV/GPS 32 at Rapid City. You would descend to 8,500 feet immediately (ATC can issue altitudes lower than depicted on approach plates under certain circumstances, but if you are leery, by all means, query ATC). Here, you would also be expected to begin your descent to 6,200 feet at 12nm from NIRYO and descend per the approach procedure thereafter. Your descent at 12nm from NIRYO is assumed by ATC because you ve been cleared for the approach. Pilots N Paws is an online meeting place for pilots and other volunteers who help to transport rescue animals by air. The mission of the site is to provide a userfriendly communication venue between those that rescue, shelter, and foster animals; and pilots and plane owners willing to assist with the transportation of these animals. A general aviation transport requires just one pilot volunteer and is far more efficient and dependable than time-consuming ground transportation for these animals who are often in danger of euthanization. Volunteer pilots retain complete authority of their planning and flights, and can give as much or as little time as they like. SIMPLE AS 1-2-3 No bothersome paperwork required! If you love to fly, and you love animals, please join us now! It s easy, it s fun, and it s extremely rewarding. Joining is easy and takes just a minute of your time. 1. Go to www.pilotsnpaws.org and register 2. Post your information and read other posts 3. Wait for contacts / make contact with others WHY JOIN THE PILOTS N PAWS NETWORK? Enjoy flying while helping a worthwhile non-profit organization Flights are tax-deductible 501c3 Expand your network of pilot/aviation contacts and other professionals Gain flight experience and log more hours Explore new geographical areas An extremely rewarding experience every time Pilots N Paws www.pilotsnpaws.org Scenario 3: From your position of 40nm west of NIRYO at 10,000 feet MSL, ATC states, King Air 12345, proceed direct NIRYO, cleared for the RNAV/GPS Runway 32 at Rapid City. You are now expected to begin descending to 9,400 feet at 30nm from NIRYO, further descend to 6,200 feet at 12nm from NIRYO, and to descend per the charted approach procedure inside of NIRYO (all without further communication from ATC). While it may seem a little complicated and even confusing on the surface, the heart of the matter is really fairly simple. It all hinges around whether ATC has issued clearance for the approach or not. If traffic is such that ATC can issue an approach clearance at or outside the TAA s outer distance boundary, doing so relieves them of needing to issue subsequent altitude or route clearances. Equally it relieves the pilot of having to follow any instructions that are not spelled out on the approach plate. In a perfect world, everyone would be in the same loop and the next communication from ATC would likely be, King Air 12345, contact Rapid City tower crossing EHGAW, and the pilot would be free to focus on flying the 18 KING AIR MAGAZINE JANUARY/FEBRUARY 2010
charted procedure. But, in reality, the world of air navigation is no more perfect then the world below your King Air. Therefore, when in doubt, mash that push-to-talk switch and confirm exactly where ATC expects you to be (vertically and horizontally). In Conclusion The TAA is yet another way that advanced avionics and the other TAA (Technically Advanced Aircraft) are helping to optimize our airspace system, or at least to increase its efficiency. Nonetheless, the responsibility to safely operate any given flight still rests squarely on the shoulders of the pilot in command. Therefore, it makes perfect sense that, in the AIM, the FAA uses a number of variations on the following sentence to keep us all honest: If the pilot is not sure of what they are expected or authorized to do by ATC, they should ask ATC or request a specific clearance. Good advice, indeed. About The Author: Matthew Mc- Daniel is a Master and Gold Seal CFII, ATP, MEI, AGI, IGI and CSIP. In 20 years of flying, he has logged over 10,500 hours total, over 4,000 hours of instructiongiven and over 2,500 hours in King Airs and the BE-1900D. As owner of Progressive Aviation Services, LLC (www.progaviation.com), he has specialized in Technically Advanced Aircraft and Glass Cockpit instruction since 2001. Currently, he s teaching clients nationwide, via personal flight training and seminars, providing contract pilot services in a wide variety of corporate aircraft. He s also an airline and corporate pilot, having flown a wide variety of airliners and corporate jets and holds five turbine aircraft type-ratings. Matt can be reached at: matt@progaviation.com or (414) 339-4990. JANUARY/FEBRUARY 2010