Monday, March 07, 2005


Landings are the yardstick by which passengers measure pilots. They like their transition from flight to terra firma to be barely noticeable. If you grease it in, you'll likely get a few happy comments as the passengers disembark. Nevermind that you may have nearly killed them half a dozen times while enroute; the fact that you greased the landing qualifies you as SkyKing in their minds. Conversely: spend two hours picking your way around TSRAs, picking up moderate ice, and shooting a non-precision approach to minimums - and then bounce the landing. Two hours of competent, shrewed airmanship are cancelled out by two seconds in the flare.

I can't really hold the emphasis on landings against the passengers - as pilots, we do put a lot of effort into our landings, and get a charge out of a really nice one. As an aside, a nice landing and a good landing are two entirely different things. A good landing merely requires that:
1. The airplane be near centerline.
2. The airplane's heading is the same as the runway heading.
3. The touchdown occurs with no sideways drifting (side-load).
4. Descent rate is slowed prior to touchdown (unless landing on a aircraft carrier!).
Professional pilots make good landings the vast majority of the time. Nice landings depend both on the pilot and the airplane. I've flown with a few captains that were very consistent on their landings, but they were never greasers. One of them told me he'd much rather have consistently good landings that weren't greasers, than try so hard to make greasers that he ended up with a few bad ones. That makes sense.

Not all airplanes are created equal when it comes to landings. Some are known to be easy, and some are notoriously hard. The MegaWhacker is one of the hard ones: it requires special technique, and is extremely inconsistent. The difficulty derives from it's length. The MegaWhacker is 107 feet long, yet is fairly low-slung, so caution must be exercised to avoid hitting the tail on the ground during takeoff and landing. On landing, we can use no more than 5 degrees of pitch while close to the ground; depending on flap setting and weight, approach pitch is usually already 1-3 degrees, so there is very little additional pitch available to slow the descent rate in the flare.

When airplanes get close to the ground, they encounter a "cushion of air" known as ground effect. This slows the descent rate somewhat, but is not enough to prevent a hard landing by itself. In most airplanes, you retard the throttles (cut the power), and pitch the nose up to slow the descent rate. In my airplane, cutting the power effects a massive descent rate, so that's a really bad idea. Since we cannot pitch up much more, we usually hold our pitch angle steady while adding a touch of power.

The problem is compounded by the sensitivity of the throttles. On a landing with the flaps set at 35 degrees, only about 2% additional torque is needed. Just bumping the throttles slightly can result in 5% torque increase. If too much power is added, the pitch must be immediately decreased or the airplane will "balloon," after which the pilot will need to cut power and the landing will be firm.

Given all of this, you can see why consistently nice landings are almost impossible in my airplane. I do occasionally make greasers - I made one of my best a few days ago - but in between them are decent landings, ok landings, and teeth-chattering pounders that leave every passenger calling their personal injury lawyers. Furthermore, getting used to landing the MegaWhacker has completely screwed up my landing technique in other airplanes. When flying the C-152 at Troutdale, it takes every inch of willpower to make myself reduce power to idle on short final, and use enough pitch to keep the nosewheel off the runway during landing.

Incidently, there are times where really nice landings are inappropriate. On a short runway, a very wet runway, a slippery runway, or in a heavy crosswind, a firm touchdown is much safer than a "greaser." Furthermore, really nice landings don't save any wear-and-tear over good landings. So really, making a greaser is all about passenger comfort, and more significantly, boosting the pilot's ego.