Arriving in Style

And let’s face it, the key to that flawless approach is often a well-planned descent. Like so many things in aviation, the preparation for that silky-smooth touchdown often starts miles from the airport while still at our cruise altitude.

In the airline world, descent planning and execution receives a lot of attention. Getting a couple of hundred thousand pounds of swept-wing jet down to sea level from 40,000 feet takes a bit of forethought and no shortage of technology. 

Most of the big jets, when faced with Newton’s laws of motion, need a little assistance when going downhill. To cope with these challenges, airline glass flight decks contain a vertical navigation function (VNAV) that keeps the autopilot, and the crew, on the right path to arrive at the final approach fix, or downwind leg, at speed and on altitude. 

Speedbrakes and spoilers abound, and thankfully jet engines don’t care much about shock cooling. These tools help the pilots deal with this busy section of the flight replete with numerous checklists, changing clearances, and traffic. 

Back down here is GA land, we have many of the same concerns. Descending back to earth from 9,000 feet on a long IFR or VFR cross-country takes a bit of planning. We have some of the same checklists, clearances, and traffic, and we have one less pilot to get them all done. 

Like so much of aviation, there are several ways to skin this descent cat. So, let’s take a deeper look at how to arrive in style. 

So, when is a good time to start planning the descent? It depends. If you are out on a local low-altitude VFR sightseeing flight, your return to the local landing pattern is one part experience and one part muscle memory. You have done this many times before and it comes naturally. 

However, on that trip to EAA AirVenture this summer, the afternoon buildups can push us up to 10,000 feet in search of cool and smooth air. The en route instrument approaches, traffic patterns, and terrain are all new. Add in the usual cumulus buildups, ATC delays, and unexpected changes, and it’s easy to get behind in a hurry. 

So, just maybe planning the descent and landing starts before takeoff? 

First, how much avgas is enough? The VFR and IFR minimum fuel requirements are just the starting point. Sadly, GA accident reports are littered with singles and twins that land just short of the runway with windmilling props and dry tanks. 

I can “legally” land my Cessna Cardinal with just 30 minutes of fuel in the tanks. However, 30 minutes of fuel looks just like empty on my 1970 vintage fuel gauges, and 45 minutes is not a lot better. So, I have decided to double these minimum fuel requirements, and plan to land with 10 or 15 gallons for VFR and IFR, respectively.

When should we review the approach (IFR) or airport diagram (VFR)? Let’s get that done before we start the descent. Anytime the airplane is heading downhill toward terra firma, our attention should be on the instruments in the clouds, and out the windows when the sky is clear. Cruising above the clouds or haze layer is a great place to start planning the arrival. The approach review should include an altitude target for pattern entry or joining the final approach so we can compute the best descent. 

Aviation is full of rules of thumb. Here’s another: Think in terms of 3-to-1 for descents. That is, start your descent in nautical miles three times the number of feet, in thousands, you have to lose. Let’s say the VFR pattern altitude is 1,000 feet, and we are cruising at 10,000 feet. We need to lose 9,000 feet. Drop the zeros, and 9 x 3 = 27 nm. I usually add an additional 5 or 10 nm depending on the airport and procedures to join the pattern, so I might round up to about 35 nm for this example. 

Any descent at or before this mileage will likely keep the engine warm and get the plane down before the final maneuvering phase of flight. Repeating this calculation every couple of thousand feet or so lets us know if the descent is still on track. 

In the big jets, the descent speeds and angles are baked into the sophisticated flight management systems. However, in GA I have noticed two distinct schools of thought.

The “speed demons” leave their power at cruise settings, roll the trim forward, point the nose earthward, and descend somewhere near or into the yellow arc. This saves a couple minutes but increases noise in the cabin and exposes you to another potential problem, which I’ll get to in a moment.

Pilots in the second major group, the “cruisers,” reduce manifold pressure and rpm, leave the trim alone, and let the nose drop. They descend at their normal cruise speed and are quite happy about it all. 

Both of these approaches work with one significant caution. We often end up at higher altitudes to escape the wind shear layer, cumulus buildups, and turbulence below. Of course, in the descent, we will encounter each of these turbulence producers again, and at a higher airspeed. 

Two limiting speeds immediately come to mind, design maneuvering speed (VA), which you’ve probably heard of, and something called “design speed for maximum gust intensity,” or VB. 

A quick check of the POH usually lets us know that both VA and VB may be below our regular cruising speed and the yellow arc. My trusty strutless Cardinal loves to descend and builds up speed quickly. However, I am always aware that VA hovers somewhere near 100 knots, and VB may be even less, both depending on gross weight. So, I am careful to watch the speed heading downhill into the turbulence. 

Let’s consider the possibility that descending through the weather and traffic towards solid ground presents an increased midair collision hazard. Long straight descents, especially on autopilot, present an increased hazard as we pass through each of the cardinal VFR and IFR altitudes. Flight following and ADS-B have lessened this danger somewhat. However, ATC workload does not always allow advisories, and ADS-B is not required in most of the low altitude en route airspace. Clearing the big blind spot posed common to your aircraft type—the wing above or below, for example—is best accomplished with a series of gentle turns to clear the airspace you’re descending into. These belly checks do not have to be abrupt but should be fairly frequent. 

Descending through a scattered to broken deck when VFR or emerging below a solid deck when IFR can also cause a conflict. It is quite legal for VFR traffic to cruise as close as 500 feet below the cloud bases. Glad we reviewed the approach before the descent started so we can keep our eyeballs outside as we emerge from the clouds.

Descending at night brings its own challenges and visual illusions. Descending on a dark, moonless night in mountainous terrain is always a concern. Descending too early can place the pilot on one side of a mountain and the airport on the other. The only warning will be the lights of the airport disappearing—and by then it may be too late. 

A better bet is to proceed over the airport then spiral down. If you are really concerned about the high terrain near the airport, wait until the morning and land when the sun is shining. By the way, this night descending illusion can even occur on final to a runway in flat, unlighted terrain or over the water. The bright lights of the airport may make the runway appear closer, and an early descent can be equally disastrous, so beware. 

We planned the descent well, cleared for traffic, watched our speed in the bumps, and now it’s time to blend in with the local aviator population and land the plane. A towered airport with an approach control can make this quite easy. Be a good listener, keep up with the clearances, stay ahead of the descent gradients, and join the final approach as directed. 

Entering a busy nontowered airport, our listening skills are doubly important. Begin piecing together a mental picture of where everyone is in the pattern, well before you turn downwind. Listening to the CTAF and looking at the ADS-B feed while 10 nm out (remembering the ADS-B is not required at nontowered fields) are a good start. If you have planned it right, arrive at pattern altitude at least 5 nm out and join the circuit. Avoid the dreaded descending downwind. It is dangerous and helps no one’s situational awareness. 

Pet peeve time. One of the cardinal sins of landing at a major airport is having little or no idea of where to taxi once off the runway. 

Thankfully, we have options. First, if lost among the taxiways and runways, fess up and ask for a progressive taxi. Better yet, use your iPad app, spring for the extra bucks for geo location, and follow the taxi diagram on the charts. And even better yet, in addition to reviewing the approach and landing before the start of the descent, take a few minutes to review the taxi diagram. Figure out which FBO you are headed for by name, where it is located, and how you might get there. Do all that in advance and you will look like an ace every time. 

With a tip of the hat to the sage of baseball, Yogi Berra, flying, much like baseball, is “90 percent mental, and the other half is physical.” The best part of flying is making a plan, preparing for the curveballs and sliders that come our way, and always trying to make the perfect flight. 

Spending quality time prior to the descent for landing to make a realistic plan, reviewing the approach, doing some simple math, acknowledging the hazards, and figuring out where the heck the FBO is located will make for a more perfect descent and landing. Having said that, none of us has ever made a perfect flight, but it is the pursuit of perfection that makes us professional.