Thread: Landings...

I was just going through the NTSB aviation reports on aircraft accidents. While at a pancake breakfast two weeks ago two acquaintances at the table took off right before us and somehow ended up in the ocean about four miles off the end of the runway. I was curious if there was any update (the reason for my inspection) as to how this happened but I don't think we'll ever know.

So while there I thought I'd look up and review all the CT mishaps...If my memory serves me correctly there was one in 04, two in 05, four in 06 and three already this year. Also if my memory serves me correct again, they we're all during the landing phase. Fortunately unlike above there has been no fatalities.

I know there has been much reported here on how to land the CT and I can't start to tell you how great full I am for that. I'm going down Monday to finally see my plane and do my transition training and the first words out my mouth for Tom will be Landings, Landings, Landings!!

As we all know this is a great airplane and as we all know all airplanes have an idiosyncrasy or two! They can be overcome through training and the continued sharing of knowledge.

So keep up the sharing and many thanks for everyone's input....because of it I know where to spend some quality time in my new CT and hopefully protect my investment.

Roger H

[i]

Roger,

I will be in Carson City mid day Tuesday, will you still be there?

I have about 350 landings now and my opinion on landing the CTSW has evolved. The newer revelation is that there are too sides to the coin. We have talked a lot about the negatives and how to avoid a poor energy state. It is highly desirable to have good control of airspeed and pitch attitude until the mains are in contact and sufficient energy is bled off. (even then keep flying the plane till it's tied down or hangared)

The positive is that the CTSW is highly maneuverable and very quick to respond to control and throttle input which means that your approach can be kept stable in gusty conditions.

With lots of flaps the CT can fly at a very slow speed so be precise when using a lot of flaps. At first it might be easy to balloon and or bounce and when that happens you may become more vulnerable because you will be slower, higher and pitched up more so go around at first. If you can settle without the balloon or bounce it will be easier to remain in a good energy state. When you balloon a little but elect to land as apposed to going around try to limit your pitch attitude and add power. For me it is very helpful to be able to visualize what I am trying to avoid, in the CT I am trying to avoid a high pitch attitude at touchdown when I'm using 30 or 40 degrees. I'm also trying to round out at 30 or 40 at a very low altitude probably under 3'. When I land with 15 degrees it is usually windy and I don't sense a round out but rather a settling in a slight climb attitude. This is the easiest type of landing for me but then you are rolling out at a higher speed.

You have the right mind set so you should do fine. Don't worry about how many attempts it takes to get a feel, it isn't a race the objective is to get the feel.

Yes Ed, I should still be there. N199CT is getting it's FAA inspection Tuesday and I get to follow the process. See you then and many thanks for the "landing" input.

Roger H

See http://www.aerospaceweb.org/question/ae ... 0165.shtml for definitions of:

Angle of Incidence
Angle of Attack
Pitch Angle.

The mean aerodynamic chord (MAC) of the wing is a line drawn from the leading edge to the trailing edge.

Assume a CTsw cruising along at 80 kts, say, with flaps up. The angle of incidence has been chosen by the manufacturer and is fixed. The pitch angle has been set by the pilot to hold the altitude and the angle of attack is that which results.

Now, lower the flaps to 15 degrees. Redraw the MAC from the leading edge to the trailing edge of the flaps. In effect, the angle of incidence has been increased. To maintain a reasonable angle of attack, the pitch angle must be lowered. Said another way, lowering the flaps results in a flatter pitch angle. Lowering the flaps more and more results in lowering the pitch angle more and more.

In the CTsw, this effect is particularly pronounced when compared to most other aircraft. At 15 degrees of flap, as at takeoff, the pitch angle which just barely raises the nose wheel off the ground is correct for lift off. This is a relatively shallow climb angle compared to most aircraft at take off. Raising the flaps and assuming a 70 knot airspeed for climb results in an increased pitch angle as the above would suggest.

If one selects 30 degrees of flap and reduces power at the base turn, the pitch angle is very much below the horizon to keep 55 knots. In fact if the engine is at idle, the nose down attitude is rather striking and surprizing at first, compared to most other aircraft. The touchdown angle is, according to this theory, also flatter than it is for 15 degree flap landings. For this reason, the change of pitch angle in the flare for 15 degree flap landings and approaches is much less than that for 30 degree flap landings. The approach and touchdown angles for a 15 degree flap landing approximates that of most other aircraft.

However, the transition from final to touchdown at 30 degree flaps must be learned in the CTsw. It isn't difficult, it is just a bit different. The 30 degree flap approach angle is fairly steep and the landing pitch angle is fairly flat, with nose wheel just barely off the ground. Increasing pitch angle too much by holding the plane off the ground can cause it to abruptly drop...this is just fine if you are just inches off the ground, but not so good if you are high.

I suspect that a part of the explanation for the more dramatic effect of flaps on pitch angle in the CTsw is the fact that essentially the flaps extend across the entire wing since the ailerons droop as well as the flaps. Flaps cover only about half the wing in other aircraft, so the effect is less dramatic.

Now, it follows that the landing pitch angle for a 40 degree flap landing will be flatter yet. In fact, it will be very very flat, almost three points. We (correctly) don't want the nose gear participating in the landing shock so we will naturally try to get the nose a bit higher and face the real possibility of a drop out. Again this is OK if you have skillfully got the gear a few inches off the ground, but very bad if you are a foot or more in the air. Recovery isn't easy with the drag of 40 degree flaps. Getting it right is a lot easier if a little power is carried.

My advice for new pilots is to learn the CTsw using 15 degree flaps for takeoff and landings. When that feels comfortable, do a lot of slow flight at the other flap settings and then work on the 30 degree flap setting landings. Only later, when your skills have developed and you want to study short field landings, work out your technique for 40 degree flap landings. Or not. The only reason I can think of to do a 40 degree flap landing is for short field work and I am not sure it would help much there. For gusty conditions and/or crosswinds, use either no flaps or 15 degrees only and increase speed. Increase speed by one half the gust value. In gusts, get set up with a little power on (and hand on the power) and cruise down the runway fishing for the sweet spot.

For ample runways, a little power on any final approach generally makes smooth landings easier, but you should practice power off approaches and landings regularly to be ready for the day when there is no choice in the matter.

Russ....an excellent summation of the characteristics of the CTsw on approach and landing.

Thankyou.

Dave

Russ,

I agree, an excellent assement. Perhaps we can get you to write an initital landing slyubus as a suggestion to Flight Design. I think you migh include a comment about the slippery airframe and the short coubpled charictaristics as well as the quick roll response due to the short wings.

I bet you are a good CFI.

Ed Cesnalis

Here is a question for you veteran CT pilots out there. Danbury Munipal (DXR) is my base field. Runway 26 is the most frequently-used runway, and it has a 500-ft (AGL) hill with a tower about 1/3 of a mile before the threshold. I have to stay high up to that distance and then I have to lose altitude fast. You know how the CT likes to keep gliding so sometimes even at idle it is difficult to get the plane down once I'm past the hill if I keep the airspeed at 60kt (60kt is very close to the best glide speed, unfortunately). As a result, my instructor and I determined that for Danbury it makes sense to use a 40-degree flap setting on final and that's how I learned to land the plane (those go-arounds at 40-degree flaps feel very weird at first, but I'm glad I did them many times with an instructor). The problem with 40-degree flaps, for me, is not so much the flair (since I've done it a million times) but dealing with crosswinds and gusts, which are quite common in Danbury.

Nowadays I tend to land at 15 degree flaps (mostly as a result of the comments on this forum), but it's a struggle to get the plane down once I pass the hill. I have to resort to two slightly undesirable techniques. I either slip the plane (not ideal, especially in gusty weather, because this is not considered a stabilized approach), or go faster than 60 kts (I can go up to 80 with the 15-degree flaps, and the plane glides much less efficiently at faster speeds thus coming down faster, but then I float a lot longer to bleed off the energy; thankfully Runway 26 is about 4,400 ft long).

Given such an obstacle on final, would you rather land regularly with a higher flap setting, or land regularly with a slip? Which, in your opinion, is the lesser of two evils?

Hi Hedger,

Can you drop down lower and come around the hill and straighten up for the runway instead of going over?
Maybe come in at a slight angle?

Unfortunately, there is no way around the hill for Runway 26. From the POH and the website, the CT's glide ratio is 14:1 at idle with 15 degree flaps at 63 kts. According to the A/FD, the approach ratio is 11:1 for Runway 26 at DXR. Therein lies the problem.

I don't have experience with the CT but since I started looking at planes with short ground rolls I realized the advantage of changing my landing philosophy. Instead of aiming for the numbers with a short roll plane I just decide how much of the runway I can fly over before I go around. Unless you have a very short runway a little float shouldn't hurt you unless you are one of these macho pilots who like to brag about making the first turnoff. Of course you could make the argument that if you don't aim for the numbers you won't be prepared for an engine out with only a short field available. I fly single pilot single engine IFR in IMC over hostile terrain and it always amuses me that other pilots who do the same suddenly worry about keeping a tight high pattern at the airport so they can make the runway if they have an engine out.