Old School Navigation: DIY Visual Approach Charts

In the olden days before the advent of moving map GPS but following the bad old days of the four course, navigation was a mix of pilotage, NDB and VOR tracking. The aircraft I’ve flown recently all have either a large GPS, a glass panel or a combination of both. That doesn’t mean that I always use them as a primary means of getting around. Call me crazy, but looking out the window is a lot more fun than staring at a screen.

I was fortunate to have instructors in my formative years who were old school navigators. They knew how to use GPS like wizards but wouldn’t let me use it until I had figured out how to read a map. After all, the map on the GPS is a repeater of sectionals and enroute charts that pilots used to carry before the iPad was invented. Knowing how to read one means knowing how to read the other. I was taught to look for checkpoints that were not directly under me (or at least offset myself by a 1/2 mile so I could see something prominent), not to draw a course line from the middle of an airport to the middle of another (unless you make a Dutch F-16 style takeoff, or fly out of ADS, not many people turn on course by midfield) and most of all, to verify the correct checkpoint by referencing it with another landmark.

One problem I had in parts of NJ and PA was finding certain airports. I knew where they were based on planning, they just had a pesky tendency to be hidden by trees and hills. We never flew much above 3000 MSL for the obvious airspace reasons, thus my limited line of sight in some areas meant that a few airports didn’t reveal themselves until the last second (at least on the first trip to a new field). Annoyed by this, I started drawing my own visual approach charts and still do to this day. It’s fun and gives you something to work with when flying into an unfamiliar field.

This technique works really well in densely populated areas also, day or night. Usually the airport is the dimmest set of lights out there and it’s hard to resist the urge to focus on a shopping center or highway just beyond the rotating beacon. For the approach into ADS from the north, an easy way to get in is to be north of the Sam Rayburn Tollway and the Dallas North Tollway intersection when you call up Regional Approach. At the southeast corner of this massive intersection is the huge headquarters of Hewlett Packard which actually is a charted VFR checkpoint (formerly Electronic Data Systems, hence the EDS on the chart). Follow the Tollway south and when you pass the next spaghetti-bowl intersection of the George Bush Tollway and the Dallas North Tollway, you are 2.7nm from ADS. Chances are unless you’ve been there before, you won’t see the airport but may see the beacon (it is literally in the middle of a city). Just keep following the Dallas North Tollway. Whoever built it must have been a pilot because at the 45 degree pattern entry point, it turns to you guessed it…a perfect downwind leg for Runway 33. Look to your right and you’ll see the airport if you’re at pattern altitude.

The Addison “Tollway Visual Rwy 33” sets you up for a right downwind entry.

Satellite terrain view of the densely populated North Dallas area and how congested the boundary of Addison is.

Getting back to 47N at night after returning from Long Island was made simple by using a natural landmark. I followed the Raritan River until it literally dumped me out on extended final for Runway 25. Starting You’ll pass over a wide freeway bridge, the NJ Turnpike/I-95. When you pass this bridge, a quick look to your left (south) should reveal the 2 Tower Center, which is as you probably guessed, two tall office buildings. Due west of I-95 is the Rt 1 bridge, followed soon thereafter by a series of highway bridges and a railroad viaduct linking New Brunswick to Highland Park. On the north side of the river at this point is the Rutgers football stadium that occasionally has a TFR but if there are no lights on, there shouldn’t be any issues (NOTAMS or a quick call to NY Approach keeps your conscience clear). Keep going and you’ll see I-287 making an “L” in front of you (and crossing the river). Just after this, the river will curve to the left, you’ll cross I-287 again and when the water becomes difficult to see, look up and you’ll see Runway 25 directly in front of you.

River Visual for Central Jersey Regional Rwy 25.

Satellite terrain map view of approach into Central Jersey Regional showing how the river narrows as the airport is reached.

Nearby 47N is SMQ, which is from some angles hidden by trees. Follow I-287 to the north and when you are parallel to the large Aventis Pharmaceutical facility on the right, look to your left and the airport will be there. If you happen to miss it from this angle, continue north until reaching the juncture of I-287 and I-78. Turn west to follow I-78 and look to your left again. The airport is in the southwest corner of this juncture less than a mile from your position.

Somerset Airport visual approach following I-287 with multiple reference points.

Wider view of the “inital” fix into SMQ.

Going to Newport State, RI? From the west, follow the Jamestown Bridge that crosses Narragansett Bay. When the highway bends sharply to the south, continue to the east. Cross the bay, pass over the Newport Naval Complex and cross highway 114 (north-south orientation) and you’ll be midfield for UUU.

Newport State Bridge approach. Note obstructions on the Newport segment of the bridge.

Wide view of approach over Narragansett Bay and the Naval Facility.

These are just a few of my personal examples and I’m sure you have your own for fields you fly into. The advent of satellite maps online has made it easier to cross-reference ahead of time what the terrain looks like rather than looking at yellow vs tan vs brown on a sectional. Plus the ability to see what buildings are near your destination airport is a vast improvement over trying to guess which warehouse or mall to look for while airborne. While I would rather fly with a moving map as a bright and shiny cross-reference, I have no issues going without one. Planning makes all the difference in being where you want to be vs someplace else. Happy navigating.

Advertisements

Six Degrees For Separation: One Way To Solve The DFW Airspace Issue

The airspace over Addison (KADS) is slated to be changed soon if the FAA proceeds with its plan to reduce congestion into Dallas Love (KDAL) and Dallas/Fort Worth (KDFW). The airspace change includes a lowering of the Class D over Addison from 3000 MSL to 2500MSL. While that may not seem like much, it is in an area where operations are already in a very tight fit with DFW traffic to the west, DAL traffic inbound from the east-northeast and large amounts of corporate, fractional, cargo and training traffic underneath at ADS. In fact, the final approach fix (JERIT) for ADS rwy 15 is at 2000 MSL, which would leave only 500 feet separation between IFR arrivals into ADS and DAL traffic at 2500 if this airspace change goes through. As it stands, ADS is already the busiest GA airport in Texas and in the top 5 in the United States.

The area of concern: The 3000 MSL roof of Addison's class D is slated to be lowered to 2500 MSL, leaving very little space for aircraft as big as MD-80s and 737s to maneuver. The proximity to DFW and DAL is noteworthy.

The area of concern: The 3000 MSL roof of Addison’s already highly modified class D is slated to be lowered to 2500 MSL, leaving very little space for aircraft as big as MD-80s and 737s to operate. The proximity to DFW and DAL is noteworthy.

There are numerous ways to avoid having to redesign the existing airspace. Although I’m sure some will suggest vectoring airliners further to the north and west before their southbound turn towards DAL, this is not efficient with respect to the jets. Anything that increases fuel consumption for the airlines is not only irresponsible environmentally, but financially. Likewise, the hundreds of businesses that rely on ADS should not be marginalized in the effort to reduce the impact to airliners. I am not writing this from the standpoint of “big airliners are against little piston planes”. Instead, I am writing this as the result of several years of observing, studying and testing new methods of utilizing existing airspace. After reading the NPRM on the changes to DFW’s airspace, I came to the conclusion that people may not be fully grasping the true capabilities of modern jet airliners.

The upside-down wedding cake design of Class B airspace is optimized for steep climbs and descents. Standard Class B has a floor gradient of 300 ft/nm out to the 10nm ring. This equates to only 1000fpm at 200ktas or 1250fpm at 250ktas. But again, this is for the floor and operations in excess of these values would be well contained within the airspace. With the advent of RNAV STARs and GPS approaches, creating 3D highways in the sky is no longer a fantasy but an easily employable system that works in VFR or IFR conditions. The only way to fit more aircraft into the volume of airspace already set aside is to increase the angle of descent at critical segments inside the Class B.

For separation and flow purposes, many congested terminal areas drop arrivals down 30 or 40nm out so that departures can climb unobstructed above them. This is because in areas like the DFW Class B, the proximity of DFW, DAL, ADS, AFW, NFW, FTW, GKY, GPM and RBD makes it very hard to get everyone where they need to be at the same time. When most of the non-RNAV STARs were designed, it was hard to conceptualize how to position aircraft three-dimensionally. Now that airliners and many corporate aircraft feature VNAV, FPA symbology and the ability to climb or descend in excess of 2000fpm, being able to follow a constant descent path is much easier to plan and execute.

As mentioned before, the standard floor gradient for Class B is 300ft/nm. Modern jet aircraft can climb at more than twice this rate under most conditions. Descending is actually more difficult to manage in some cases as an angle which is too steep will preclude deceleration to flap and gear speeds. Testing this theory in various sims, talking to pilots of different aircraft and flying the procedure in real aircraft has shown that an average glide angle of 6 degrees results in a power-off approach with no increase in airspeed (in reality the range was roughly 4.5 to 7.0). Depending on configuration, very low levels of power may be required to maintain airspeed. This power setting will invariably be less than that used during the current step-down method of approaching. This has tremendous advantages for noise abatement, fuel conservation, airspace utilization and wake turbulence avoidance.

Jets are not as responsive as light GA airplanes in the approach phase which is why a 6 degree glide path converts to a standard 3 degree glide path at some pre-dplanned distance from the runway, most likely 1500 to 1000 AGL (depending on the aircraft type and wind conditions). Further out in the Class B airspace, descent angles can be more conventional if satellite airport conflicts are not present, allowing jets to “pre-configure”; going to a minimal flap setting that would produce enough drag to keep speed from increasing in the descent. Some aircraft that are extremely clean with high inertia such as the A330 and B777 may require shallower angles or the use of speedbrakes.

Using this type of approach in the northeast sector of the DFW Class B would bring Love arrivals over Addison between 3000 and 4500 MSL (depending on where they are vectored from). This is a substantial safety margin for both Addison and Love arrivals. An additional benefit is that Love’s lateral spacing would not have to be modified from what exists today, reducing the potential for conflict with Dallas/Fort Worth traffic on the Cedar Creek Six arrival when a south flow is in use. Around the DFW Class B, departures leave the terminal area on north, east, south and west headings, while arrivals enter on northeast, southeast, southwest and northwest headings. This existing deconfliction works well with 6 degree descent angle as departures would not risk losing separation with arrivals.

The whole idea behind the 6 degree approach is to use what we already have without making any particular group of operators have to suffer. If the procedure works well in our airspace, it can easily be implemented nationwide for reasons as varied as traffic management, noise abatement and reduced emissions. Please try this procedure in whatever simulators you have access to. An example to test out is DAL runway 13L, crossing WADES at 7500 MSL, NITER at 1900MSL and conducting a normal visual or ILS once crossing the FAF. Since this is an angle-based and not a rate-based procedure, your VS will change as you descend and or change airspeed.

KDAL ILS 13L 6 Degrees

Runway 13L Dallas Love. Note the modified IF crossing altitude to produce a 6 degree glideslope to the FAF.

If you want to convert any IAP to a 6 degree variant, simply decide what your conversion altitude or intersection is (when or where you go from 6 to 3 degrees) and how far back from that point you want to commence the approach. Applying basic trig will net you the IF crossing altitude. For example using DFW’s runway ILS 17L:

FAF = GBUSH, 2300MSL

IF = RIVET, Unknown MSL, 12.6nm from FAF

sin descent angle x distance to FAF x nautical mile in feet + FAF altitude

((sin6 x 12.6) x 6076)) + 2300 = 10302 MSL at RIVET

KDFW ILS 17L 6 degrees

Runway 17L Dallas/Fort Worth Intl. Notice the modified crossing altitude at the IF.

In the meantime, please send the FAA your comments and suggestions on the proposed airspace change. My solution is not the only one and the more minds that work on this issue, the better.

http://www.regulations.gov/#!docketBrowser;rpp=25;po=0;dct=PS;D=FAA-2012-1168