Final approach to Runway 5
During my career as a commercial pilot, I have flown the VOR approach to runway 06 at Mazar-E Sharif, Afghanistan, in the Hindu Kush Mountains at night, the ILS 10 approach over the beach with spectators at St. Maarten Island, and even flew the VOR/GPS circling approach in a Boeing 747 to runway 13L at John F. Kennedy International Airport after flying across the pond, aka the Atlantic Ocean. But the approach to runway 05 at Casa Grande, Arizona, must be the craziest of them all.
While conducting an instrument checkride at Deer Valley Airport in Phoenix, AZ, a flight instructor briefed me that I needed to depart Deer Valley Airport using the Deer Valley 3 Departure, obtain a clearance to fly through the Bravo Airspace at Phoenix Sky Harbor Airport, make a radio call to request the “Top of Stack” on the Casa Grande Airport Unicom frequency, enter the holding pattern procedure turn at the “Top of the Stack” and more.
I was dumbfounded and advised the instructor that I just needed to do an ILS as part of the checkride test and that I certainly did not need to do what he suggested. Well, I quickly learned that Phoenix, with its sunshine weather, does not need an ILS approach at every airport, and in fact, there are very few ILS approaches outside of Phoenix Sky Harbor Airport in the area.
Case Grande Airport (KCGZ) offers three approaches commencing at Stanfield (TFD) VOR, including an ILS, VOR, and RNAV (GPS) approaches. The approaches include a holding pattern procedure turn to line up with the runway. The kicker is that you are never the only one who wants to shoot this approach. All the airplanes enter the holding pattern and stack upwards at five-hundred-foot intervals. You make radio calls on Casa Grande Airport Unicom frequency, but you address the radio calls in the VOR stack to “Stanfield Traffic” (the name of the VOR).
To start, you call “Stanfield Traffic” when you are about 5 minutes out and request the “Top of Stack” while stating your position, distance, altitude and time from the Stanfield VOR. It sounds something like this: “Stanfield Traffic, Cirrus 123 is 5 minutes North of Stanfield, 4,500 feet, request top of stack.” A response might be: “Stanfield Traffic, Skyhawk 234 is at top of stack, 5,000, 5,500 open.” You respond: “Stanfield Traffic, Cirrus 123, 5 minutes North of Stanfield, 10 DME, taking top of stack at 5,500.”
The lowest airplane in the stack will report the “procedure turn inbound” on their final turn in the stack, report crossing the Stanfield VOR inbound, and state that the “approach altitudes are open.” Yesterday, my checkride candidate and I were approaching the Stanfield VOR to conduct an ILS approach to Runway 05. We made the requisite radio call to “Stanfield Traffic,” and the response came back from an airplane at 6,000 feet. She stated, “Top of Stack is 6,000 feet, 6,500 feet open.” We advised that we would be taking the new top of stack at 6,500 feet and entered the stack.
When the bottom airplane crossed the Stanfield VOR inbound and reported “approach altitudes open,” the next airplane up in altitude at 4,500 feet announced it was leaving that altitude for the approach altitude. (This call is intentionally different than stating a specific altitude as the approach altitude could be 3,800 feet or 3,200 feet depending on the instrument approach you are conducting. The next airplane announced, “Stanfield Traffic, Seminole 357 is 5,000 feet descending 4,500 feet, 5,000 open, Stanfield Traffic.” Every airplane in the stack does this in sequence. We eventually worked our way down from 6,500 feet, to 6,000, 5,500, 4,500, approach altitude at 3,200, and then were able to shoot the ILS approach to runway 05.
After the approach, we flew the first portion of the published missed approach procedure. If we had wanted to conduct another “30+ minute” approach at this venue, we would need to start over, request the “Top of Stack,” and follow the same procedure. Rather than put my checkride applicant and me through this adventure again, I usually head over to Coolidge Airport (P08). Coolidge offers its own peculiarities, such as a non-standard traffic pattern, a VOR approach that does not line up with the runway, parachute jumping from very high altitudes, and what is often referred to as “the other stack.” I still find it less busy than Casa Grande (although a lot more pilots have discovered my secret place); it offers a variety of instrument approaches, and I can always get in a circling approach.
The Arizona Flight Training Workgroup (AFTW) www.aftw.org is an active group that provides helpful guidance for the peculiarities of this extremely busy training environment. Here is an excerpt from what I found on their website:
“Practice Instrument Approach Procedures at Casa Grande. This document is available online at www.aftw.org. The following procedures are recommended in an attempt to develop standardization among all pilots that use the Stanfield VOR and the Casa Grande instrument approaches. This letter is not intended as a directive. It is intended to serve as a tool to communicate the training industry’s desires. Any questions or concerns about these procedures are welcome by contacting the Arizona Flight Training Workgroup (see website address above).
Pilots should carefully monitor the Casa Grande AWOS before making their initial call 8 to 12 nautical miles from Stanfield VOR (TFD) on 122.7 to request “top of stack.” The aircraft occupying the “top of stack” will respond with their altitude to inform the approaching aircraft. The approaching aircraft will then respond by giving their position in miles, direction from the VOR and altitude, estimated time of arrival at TFD, as well as announcing that they will occupy the “top of the stack,” even though they are not yet at TFD. Altitude separation will be 500 feet between aircraft. Courtesy, consideration, and vigilance are what make this system work. Please abide by the altitude separation. It is understood that instructors need to instruct. However, they must also monitor and work their position in the stack.”
If you ever get a chance to visit “The Stack,” I hope you enjoy the experience. But if you’ve never been there and are flying overhead at flight levels, dial up the Casa Grande Unicom frequency just to see what’s going on.
