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I believe we have all read more than one article describing how to make good landings. I think we can all agree that using a stabilized approach should result in a good landing, the kind of landing where the flight attendants can smoothly walk the aisle collecting the last of the beverage cups and empty Goldfish packages.
There are groups of pilots who seldom use a stabilized approach because the variables of most of their landings make that difficult, and their normal landing is to use a flexible approach with almost everything varying except the final contact with the ground.
I’m not sure I can name all the groups of pilots that are in this category, but those that I can think of are: bush pilots, military liaison pilots, crop dusters, and many glider tow pilots who are limited by space or time factors. Getting on the ground quickly or into a too-small or non-standard area that may pass for a runway, will determine how it is approached. A stabilized approach is best for normal flying but is a luxury that some pilots don’t have.
Bush pilots don’t usually have the luxury of making a stabilized approach.
These pilots have made enough stabilized approaches and the resultant good landings to know what it is like to touch the ground smoothly even if everything on their variable approaches is wildly chaotic. The chaos is expected and through practice, mastery is achieved. With time it may be difficult to land using a stabilized approach. It may just seem too strange.
Crop dusters usually have the seasons working against them—crops ripen according to the season as light and temperature move north. Some dusting operations move with the growing season; some dusters remain local and do repeat applications of chemicals when needed. There is usually lots of area to treat. All dusters are subject to the weather and must make optimum use of flyable time. Getting on the ground quickly for refills is necessary. There are no beverage containers to collect, and the shortest distance between two points is still a straight line. Traffic patterns are not normal. Since dusting or spraying has been described as flying low altitude aerobatics all day long, the landing approaches are no exception.
Tow pilots often have time restraints as well. Getting gliders in the air when the thermals are strongest is the goal, and everyone wants to be in the air simultaneously. Short return times are desired, returning from the direction of the most promising looking source of lift, a billowing cumulus cloud. That often results in a downwind landing. Trailing a usually 200-ft. long towrope adds more challenge, especially if operating from a relatively short, tree-lined field. Almost every landing is a high approach over the trees until the rope is clear. That is often followed by a steep descent using maximum slip and/or full flaps until almost touching the runway. Another (time consuming) option is to drop the rope on one low pass over the field and then return to land with less challenge.
Bush pilots have many challenges. First, they might be landing at places that aren’t airports. In fact, the places they land are often not even thought of as places. They could be a beach, a stream bed, or an uphill glacier. If there is somewhere you want to go, they seem to be able to get you there. It does have to be clear of trees or large rocks, but they seem to be able to land an airplane like it is a helicopter. There are short field landing competitions, usually flying Piper Super Cubs, Cessna 180s, 185s, or similar high wing aircraft with huge low pressure tires that repeatedly land in about twenty feet.
The approach is not at all normal. It is stabilized however, in that once they slow the plane down to below normal stall speed in a very high angle of attack, power is all that is preventing a stall. They slowly approach the landing zone just “ hanging on the prop.” It takes lots of practice, hopefully done first at high enough altitude for stall recovery before it is in regular use. It’s always precarious—you’d better be really good or stay away from places like Alaska or northern Canada.
Pilots of military aircraft whose designation began with “ L” during World War II, Korea, and maybe Vietnam, and were used primarily for target spotting, shared most the challenges of bush flying where no standard landing site was available much of the time. Similar landing techniques were required in the L-1 to L-19.
I definitely agree a stabilized approach is the best way to have a smooth passenger or flight-attendant-pleasing landing. Practice and master these before you try landing in the other super flexible manner, because the only thing they share in common is to be stabilized—but only in the last six inches above the ground.
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George, you’re right about most pilots not benefiting from stabilized approaches every time.
The need for stabilized approaches arrived with the jet age. To fly fast jets need small wing area which equals high wing loading. To fly as slow as possible for takeoff and landing jets need the most effective flaps possible, both leading and trailing edge.
Flaps add low speed lift, but also add lots of drag. Because a jet is in a very high drag configuration on approach it can decelerate rapidly and a high sink rate will develop. Also–particularly with early turbojet engines–there is a considerable period of several seconds required for a jet engine to spool up and provide more thrust after the throttles are moved.
To avoid rapid loss of airspeed and high sink rates jet pilots need to maintain a stable speed and sink rate for the final portion of the approach.
While a stable approach in a prop airplane works fine, it’s not essential as in jets. Piston engines, in particular, accelerate rapidly so quick changes in thrust are available. And the wing loading and flap drag of a prop airplane isn’t the same as jet so airspeed and sink rate changes can be managed successfully, as you point out.
But, pilots who are training for a career in jets, need to learn stabilized approaches in piston training airplanes. I understand that requirement, but I sure do hate to be behind them on final as they maintain Vref +10 all the way in from the marker in a Cherokee. :)
Your comment about following slow traffic is why my final is on occasion, “dynamic:” My one-runway home airport can be _quite_ busy with Gulfstream and Citation jets mixed in with flight school Cessnas, as well as Bonanza and Cirrus traffic. To accommodate the faster traffic, it’s not terribly uncommon for me to be on final with idle throttle, trimming and putting out flaps, slowing all the way to the flare.
This article and your comment bring up a salient point, Mac. While beginning and GA pilots should know about and be able to perform a stabilized approach, many times they have to fly a fast approach and then transition to a normal 1.3Vso speed — or less — in prep just before landing … often under the duress of lots of high speed traffic behind them. THAT would be more important to a GA pilot … getting rid of that extra energy. No one ever talked about energy management when I learned to fly 50 years ago. I had to learn it the hard way.
I like how this comment is worded because it describes how things could go badly in a jet in an unstabilized approach. In my opinion, the importance of understanding the pitch stability characteristics of your aircraft generally applies to both jet/turbine and piston aircraft. In a piston aircraft the risk may lie in a pilot (perhaps inexperienced and/or low proficiency) while on an approach, inducing pitch oscillations that they spend a lot of attention on fighting, perhaps all the way into the landing, including the last 6 inches. This depletion of attention span can certainly lead to frightening experiences and poor outcomes.
George Frost, a great article!
Mac McClellan a great addendum!
Cheers,
Indeed.
I’m thinking that a really stable approach for a bush pilot would be to get a helicopter instead endlessly modifying Super Cubs to reduce the landing roll another couple of feet.
I would add another type of non-stabilized approach. At the Class C airport I fly out of, there is a lot of airline, military and other traffic. If you are a GA aircraft on an IFR flight plan, but are given a visual approach, don’t be surprised if you enter the pattern on a downwind or extended base 5,000 feet above pattern altitude. This calls for speed brakes, gear down, full flaps and a “dive” at maximum flap speed to make it down. Yes, you can always say “unable” but good luck – you may end up being vectored for the next half hour. The good news is that a decent landing can be pulled off after the “big dive”.
Lack of stabilized approach is a good catch-all for explaining an “unsuccessful landing” but an experienced pilot should be able to delay the stabilization to the important point that George Frost highlights.
Often flying a Partenavia twin P68C from Cleveland to O’Hare I would also often receive a routing of 6,000 feet over Midway, which abuts ORD. The first time it happened I was cleared for the landing from that altitude. (I can still hear the chuckles of the controller.) My “stabilized” approach wound up being over 5,000 feet of slipping the aircraft (which it did very well) down to an otherwise normal landing.
landing.