As in the title of my column, you can assume that the article will be somewhat lengthy as each item could be a college term paper. Because all airplanes are different in their flight characteristics, airspeeds, locations of controls, avionics and the weather conditions pertaining to the flight, I am using the following for this article:
- Airplane (Beech Bonanza Model P-35)
- Density Altitude (Less than 3,000 feet)
- Approach (Precision ILS Approach with DA less than 250 feet AGL)
- Weather Minimums (Near minimums for the approach selected)
- Wind (within 30 degrees of final approach less than 5 knots)
- GPS Navigator (Garmin GNS-480)
- Autopilot (S-TEC 50 with yaw damper & GPS steering)
- Ground Facilities (All ground facilities VOR LOC GS ADF working, no NOTAMS)
You can use this information as a template to construct your own flight profile after reviewing this article.
The procedure we will be flying for the purpose of this article is the ILS 09 to the Rhinelander, Wisconsin Airport (KRHI) — see the approach chart (Fig 1). This approach will go missed to enter the published holding pattern at ARSHA. We will be doing the full approach using the RHI VOR as a transition and a procedure turn. We will be fully using the autopilot with all its capabilities.
CHECKLISTS: I use a written checklist for all operations on the ground and only while stopped as to avoid taxiing into anything on the ground. I never use a written checklist in flight, but rather I use acronyms and flow patterns and voice callouts from my navigator during flight. Example: Final approach landing checklist at Glideslope intercept is (GUMP): Gas fullest tank on the Bonanza, Undercarriage landing gear down with green light — my hand stays on the handle until I see the green light, Mixture is set to full rich which depends on density altitude, the Prop is set to climb RPM of 2500, not takeoff which is 2700 RPM for nose abatement when practical.
As we approach the airport from the south about 20 miles out at 5000 feet, I will check the weather via the ASOS and find “wind calm 300 overcast, visibility 1 mile, light rain and drizzle.” I elect to do the ILS 09 approach. (Why in this day and age would anyone do an ILS with a GPS approach available with the same minimums?) (Answer) For the purpose of this article! After making my decision, I realize having done this approach numerous times before that, I am speaking with the final controller that will facilitate this approach on frequency 133.65 Mhz. Call: “Minneapolis Center, Bonanza 38Y has the Rhinelander weather and requesting the ILS 09 approach with the RHI transition.” Center: “38Y, you can expect that, proceed direct to the RHI VOR, maintain 5000, approach clearance in 10 miles.”
BUTTONOLOGY: It is now time to load the approach. Every GPS navigator is different, and this would be true for your navigator if it is a Garmin GNS-480. When putting a flight plan into the navigator, if a waypoint listed in the enroute portion of the flight plan happens to be a part of the approach you are using, then your box will auto sequence through the approach with no other action from the pilot. In this case, I loaded the RHI VOR into the enroute portion of the flight plan prior to takeoff. The RHI VOR is also the first waypoint in the approach sequence that I loaded. What this means is, I do not need to select “ACTIVATE APPROACH” once I have loaded the approach. If I had not selected the RHI VOR, I would have created a discontinuity between the two fixes that were not the same and the navigator would not know what to do upon reaching the last waypoint in the enroute segment of the flight plan. This discontinuity is like a block and the navigator is confused upon reaching it. On the GNS 480, the pilot must select “remove discontinuity” which is now shown in the flight plan or select direct to the first waypoint that is part of the approach sequence. On other Garmin boxes, the pilot would select “procedures” then “activate approach.”
In about 10 miles, Minneapolis Center calls and gives us our approach clearance: “38Y is cleared for the ILS 09 approach to the Rhinelander Airport, maintain 5000 until established on a segment of the approach, report procedure turn inbound.” Reply: “5000 until established, cleared for the ILS 09 Rhinelander approach, report procedure turn inbound 38Y.”
This readback is important because it is the last time we talk with Minneapolis Center until we are procedure turn inbound on the approach. We have verified the approach, the altitude, the fact we are cleared to do the approach as published and where is our next radio report. By putting 38Y on the tail of the readback, tells ATC who made the readback.
Acronym: Upon reaching the fix where the approach begins, I will use the acronyms referred to as the “5T’s” “Turn-Time-Twist/Track-Throttle-Talk.”
It is important to note that all of the 5 T’s are not used on all occasions, but it helps us avoid forgetting an important item. If I use any one of the 5 T’s, I review them all when crossing a fix or waypoint; in this case, it is crossing the RHI VOR. The airplane is on autopilot with GPS steering enabled, and as we approach any waypoint in the flight plan, there is a distinct ding from my navigator telling me that we are approaching a fix or waypoint, and the airplane may be turning.
I hear the ding and 10 seconds or so later, the autopilot starts the turn outbound on the transition. This is a trigger for the 5 T’s. The autopilot is doing the TURN, there is nothing to TIME or TWIST as we are using the GPS assist to get us established on the outbound leg of the approach. Remembering our clearance, we look at the approach chart and see that the altitude for this leg is 3500 feet, so THROTTLE is reduced to begin a descent, and altitude hold is disengaged on the autopilot; next TALK will be procedure turn inbound.
BY THE NUMBERS: It is now time to descend from 5000 feet to 3500 feet, and we know from training that this airplane needs 17 inches of MP to descend at 500 feet per minute, as we reduce power on the throttle.
BY THE NUMBERS concept has been around and used in training during WWII, but became popular in general aviation training after the book written by the late John Eckalbar was published (see footnote below).
As we reach our target altitude of 3500 feet as published on the approach chart, I reengage altitude hold on the autopilot and watch the airplane level off and the airspeed magically slow to 110 knots — the perfect airspeed for an approach in a Bonanza.
When training to fly a specific airplane, it is necessary to create a graph and continue to try different combinations — landing gear, flaps, drag devices, and power to achieve the desired results (Fig 2).
We are now level at 3500 feet, and as we approach the initial approach fix (ARSHA), we hear the ding created by the navigator. This would be another occasion to use the 5 T’s, but there is nothing that will occur on this approach, but we should create a habit to do so.
Should we be doing a different approach or one without GPS assist, we may need to do all of the 5 T’s.
After crossing ARSHA, we get a voice call from the navigator saying, “Localizer Alive.”
On my navigator, GPS remains the navigation source and is being flown by the autopilot, but it is a verification that I have the proper frequency of the localizer 111.3 Mhz dialed in correctly and the navigator has verified that it is receiving a signal. Other navigators will handle this differently. For example, a Garmin 430/530 will display a message light about 2 miles before the final approach fix.
After flying outbound for a pre-programmed time from ARSHA, which is determined by the manufacturer of the navigator, that familiar ding is heard again prior to the autopilot turning outbound on the procedure turn. This is again a spot for the 5 T’s acronym to be reviewed, even though no pilot input is necessary as the autopilot is flying. The next ding will be telling the pilot it is time for another turn, which is called procedure turn inbound. The acronym comes up again with the autopilot making the 180-degree turn; the pilot “Twists” in the inbound course and reports to air traffic control. “Talk” “Bonanza 38Y is procedure turn inbound for the ILS 09 approach Rhinelander.”
With one controller running many approaches simultaneously at different airports, it is a good practice to provide the controller with adequate information, rather than trying to shorten communications to save on frequency congestion.
ATC replies, “38Y, radar service is terminated; switch to advisory frequency is approved.”
This communication tells the pilot that he may switch to the Rhinelander advisory frequency of 123.0 Mhz, but not change his assigned transponder code. No more communication is needed with ATC until the pilot lands and cancels his IFR or needs to go missed approach. The pilot should never cancel his IFR clearance in flight until he is 100 percent sure he will be able to land.
The pilot of 38Y replies, “38Y, switching to advisory.”
The pilot acknowledges because in aviation communications protocol, the pilot is to talk last.
At this point in the flight, it starts to get busy. The pilot of 38Y switches radio one to the communications frequency of 123.0 and decides to recheck the ASOS weather on radio 2 frequency 126.825. With the autopilot flying the airplane in GPS steering mode, the familiar beep alerts the pilot that the aircraft will be turning to an approximate heading of 091 degrees as it intercepts the final approach course. Once inbound, the computer-generated voice again meeting programmed criteria, announces localizer alive and switches from GPS to VLOC mode.
It is important to note that all navigators do not have the voice function, nor do they make the switch to VLOC without pilot interaction. I suggest pilots fly approaches in a controlled VFR environment and decide the best way to make the switch from GPS to VLOC on their navigator. Does it work well automatically, or should it be manually done by the pilot? Some autopilots will turn completely off when switching from GPS to VLOC… others change to wings level mode, and some require pilots to change autopilot inputs from digital to analog mode.
As I approach ARSHA as the final approach fix, we see the glideslope becomes alive from above and starts down. Prior to reaching glideslope intercept, I do one last glance at the approach chart noting the Decision Altitude DA/MAP and the initial part of the missed approach procedure.
As I glance at the approach chart, we see ARSHA displayed as a Maltese Cross and a vertical line with the numbers 3477 shown above it. Prior to this, there is an underlined 3500 with an associated lightning bolt symbol nearby. This tells the pilot that the aircraft will intercept the glideslope prior to reaching ARSHA at 3500 feet, and the glideslope will cross ARSHA at an altitude of 3477 feet. It also tells the pilot that the final approach fix is the lightning bolt and not the Maltese Cross if this is a precision approach with an active glideslope. If the glideslope is out of service for this approach, then the approach becomes a non-precision approach and the Maltese Cross ARSHA becomes the final approach fix. Pilots have a precise method of determining the exact location of ARSHA by three methods: (1) the outer marker beacon will flash and sound off, (2) the ADF needle on a frequency of 272 KHZ will swing 180 degrees, and (3) the DME will indicate 6.8 nautical miles when tuned to the RHI VOR on 115.05 Mhz. When checking the altitude when crossing ARSHA, it should be 3477 feet, and it is extremely important to see if there any discrepancies. This could be caused by the pilot setting in the wrong altimeter setting or the aircraft glideslope being out of calibration. A discrepancy in an altimeter setting or glideslope calibration could have disastrous results, and this has happened to me on several occasions.
The glideslope has now about centered, and altitude hold is turned off on the autopilot. It is now time for the acronym, GUMP, followed by a flow pattern going from left to right and the 5 T’s. Gas fuel gauge check with selector on fullest main tank for the Bonanza; Undercarriage, the landing gear down (hand on gear lever till green light); Mixture (full rich for this approach); Prop set to 2500 RPM. The 5 T’s on this approach — Turn (not on this approach); Time (to missed approach point if no glideslope); Twist (nothing to twist on this approach); Throttle (to 17 inches if not there); Talk (report final approach fix on common traffic advisory frequency).
The 50 autopilot has altitude hold but will not capture or fly a glideslope, so it must be done manually by the pilot. The Bonanza is an extremely good instrument platform, and with just the lowering of the landing gear at glideslope intercept, the aircraft needs very little input to maintain the proper descent on the glideslope. As the Bonanza descends on the glideslope, manifold pressure increases and needs to be adjusted by the pilot. It may be necessary to adjust the manifold pressure slightly should there be a change in windspeed or direction on the approach. Every aircraft has its own set of numbers on an approach; the Bonanza speed is 110 knots and does not need any flaps, but some other aircraft do. Many pilots try to fly their aircraft too slow on the approach, making it difficult to maintain glideslope in turbulent air.
Approaching decision height of 1823 feet in IMC conditions with no runway in sight, it is time to execute the missed approach procedure. There are several acronyms that can be used; the one I use is 3 Up’s — power up, pitch up to positive rate, and gear up. The airplane is still on autopilot and trimmed for 110 knots and with the added full power and reduction of drag from the landing gear retraction, it begins to climb with little input from the pilot to maintain that airspeed. Passing over the runway threshold on the climb, the navigator voice calls “Missed Approach” and switches from VLOC back to GPS with no pilot intervention.
The missed approach procedure on the Garmin GNS 480 is different from any other navigator box that I have used, and because the autopilot was never manually disconnected by the pilot or software, it makes for an easy missed approach procedure. The aerodynamics principle that we trim for airspeed creates the pitch up when power is increased and drag is reduced. Should you be flying with a different navigator or autopilot, the results of the missed approach would be quite different. It may be necessary to turn off the autopilot at decision height or it would follow the glideslope to the runway fighting the increase in power and reduction in drag. Hitting the Go/Around button on a flight director autopilot will disconnect the autopilot, allowing the airplane to pitch up with increased power and drag reduction, but no directional control is provided by the navigator to the autopilot. On aircraft with autopilot envelope protection, pitch is established by the autopilot and wings are level with no directional guidance. Most navigators require the pilot to select what needs to be done next, flying a heading or course, and climb to an altitude in altitude preselect. The navigators also require the pilot to switch from VLOC to GPS for the missed approach.
Flying on the autopilot under the direction from the navigator and climbing, I review all of the 5 T’s with the last one being Talk. I switch the radio back to 133.65 Mhz. “Minneapolis Center, Bonanza 38Y missed approach Rhinelander and flying the published missed approach.” The Garmin GNS 480 is now guiding the aircraft path via the autopilot and knows that upon reaching an altitude of 2100 feet sensed from the air data computer, it must turn right and proceed to the missed approach holding point at ARSHA. Having no altitude preselect, I must press the altitude hold button on the yoke reaching 3500 feet as published on the approach chart. Leveling off I know from my “by the numbers chart,” it would be wise to reduce power to 17 inches for a holding speed of about 110 knots. As we continue toward ARSHA, the navigator calculates the entry into the holding pattern and the air data computer provides help in establishing headings and leg lengths based on wind direction and speed. With no further input from me, the aircraft will enter and remain in the hold until a decision is made on what to do next.
With so many different avionics configurations available today, I decided to use a different format in my column to encompass numerous techniques, checklists, flows, buttonology, acronyms and by the numbers to help them fly in the IFR environment.
I would like to dedicate this column to John Eckalbar, who passed away on September 24, 2024. John was a friend, a colleague, and an author of numerous books dedicated to making flying safer and easier. RIP John, and thank you for all you did to make flying safer!
DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of their personal flight instructor and others, and refer to the Federal Aviation Regulations, FAA Aeronautical Information Manual, and instructional materials before attempting any procedures discussed herein.
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