How can I Make a Smooth Landing?

[David Vega]

Looking through some of your FSACARs flight reports, I notice that some of our pilots are having a difficult time landing smoothly. Clearly some of you have turned off crash detection, because with some of the descent rates I've seen would have certainly resulted in a crash. What constitutes a smooth landing? FSACARs metric shows your descent per minute in feet. I know, for example, that in a small airplane, like say a Cessna 172, a good descent ratio for landing is 500 feet per minutes (fpm). But that's while on final approach. You want a much smoother touchdown, since 500 fpm is almost 8 feet per second. Picture the landing gear touching down at that rate. Pretty hard, no? It sure would rattle all those little liquor bottles.

A good landing begins with a good approach. The three main factors that make a good approach and landing are speed, speed, and (here it comes) speed. I mean, slow down. When you are getting close to the airport, you can't afford to be going too fast. Yes, it's 250kts or less below 10000 feet, but you must slow down at least 20 miles from the airport. Have you noticed ATC telling you to slow down? What's a good rule of thumb? As you approach the field, gradually slow down. Set speed goals so that when you're 40 miles away, you'll be at 240kts, 30 miles at 230kts, etc. If you're doing an ILS approach, by the time you intercept the localizer, be at 180kts. In fact, be at 180kts with the appropiate flap set. This will give your autopilot, if you're using it, the chance to capture the localizer without overshooting. What next? See my next posting.

dv

[David Vega]

So, we've intercepted the localizer, are at 180kts, with the first set of flaps deployed. Continue the approach. Watch for the glideslope indicator to start moving. I'm assuming you're intercepting the glideslope from below. As the glideslope indicator moves down, slow down to 170 in a smooth motion. Don't forget to properly deploy flaps keeping flaps max extension speeds. When the glideslope indicator is between the two dots above the horizon on the attitude indicator, lower the landing gear, and slow down some more. Again, the autopilot should start a slow descent of about 800 fpm. As you get closer to the runway, slow down to Vref. When you get to minimums, if you see the runway, and everything else is configured right, go for the landing, otherwise go around. Most pilots like to manually fly the last portion of the landing. I usually disconnect the autopilot at 500 feet above ground. But you could also go for an autoland, if your aircraft is so equipped. You may not get a very smooth landing with autoland though.

If you're going for it manually, as you cross the runway threshold, gradually pull the throttle back. When you are about 10 feet of the runway, initiate a flare. This is a combination of flare a little and hold, flare a little and hold, and so on until you touch down.

Is that the end of the landing? See my next posting. Feel free to comment .

Dave Vega
STL Hub Chief

[JohnnyT]

I want to make a complement to what Dave wrote about touch down speed.

In the fleet describtion of Scandinavian Airlines on Operational Limitations:
http://www.sasflightops.com/

B737
"Hard landing limits:
More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)
If any of these values is exceeded a hard landing inspection must be performed."

Also a SAS A340/MD80 captain told me:
"During flight test one MD-81 made a touch down with 900 ft/min and they lost the tail (broke behind the engines)."

Johnny Taptos
SAX715/SAS213

[David Vega]

So, your wheels just touched down with a gentle screech, there was no jolt, and the passengers are wondering when is the airplane going to touchdown. Now what

Hopefully you remember to arm the autobrakes and/or spoilers (if your jet requires it) so while your jet decelerates, you kick in those powerfull retrorockets, also known as reversers. Turn them off at 80kts, and continue bracking. I'm also assuming you are landing below your maximum landing weight. Exit on the first available taxiway, or follow ATC instructions. You have arrived

Should you aim for a smooth landing all the time

[Pylet]

Excellent tutorial Dave! One thing I do is have the spoilers armed on approach as well as the autobrakes. Then on touchdown I bring on the reverse thrust till 80 knots as you stated and I let the auto brakes keep doing their job till 60 knots at which time I start manual braking. This will help keep the brakes cooler and keep from jolting the passengers forward with too much applied pressure. I then find the first exit, stow the spoilers and turn off the auto brakes and then start the taxi checklist.

[JohnnyT]

"During flight test one MD-81 made a touch down with 900 ft/min and they lost the tail (broke behind the engines)."

http://video.google.de/videoplay?docid= ... 6351320760

Johnny

[Dave Blake]

"During flight test one MD-81 made a touch down with 900 ft/min and they lost the tail (broke behind the engines)."

The nose gear collapsed, too.

[David Vega]

Excellent tutorial Dave! One thing I do is have the spoilers armed on approach as well as the autobrakes. Then on touchdown I bring on the reverse thrust till 80 knots as you stated and I let the auto brakes keep doing their job till 60 knots at which time I start manual braking. This will help keep the brakes cooler and keep from jolting the passengers forward with too much applied pressure. I then find the first exit, stow the spoilers and turn off the auto brakes and then start the taxi checklist.

It's interesting to note that Southwest Airline prohibits its pilots from using the autobrakes. The brakes, when autobrakes is used, have a mandatory before flight cooling period that is longer than Southwest keeps its airplanes on the ground. See http://www.ntsb.gov/events/2006/Chicago ... 347682.pdf
and
http://www.ntsb.gov/Publictn/2002/AAB02 ... tobrake%22 .

[David Vega]

http://forum.avsim.net/page/index.html/ ... art-1-r816

[shackler781]

The practical test standards for your private license requires the ability to perform slow flight, wherein you are maintaining heading and altitude while just above stall speed. This is to help you understand what the controls 'feel' like at approach speeds. You also perform stalls, not to learn to stall, but to learn the 'feel' of an impending stall so you can recognize it during non-training flight. Point being, we learn what flying 'feels' like. Though you cannot actually get all the sensations of flying sitting at your desk with a cup of coffee and Saitek controllers mounted in front of you, but I have found a real good way of 'feeling' the approach in FSX. Before I ever joined SAX, I would setup my sim for approaches at different airports with ILS, tune the approach frequencies, and activate the autopilot. I would calculate my approach speeds, enter them, and let autothrottle handle the engines. My entire approach was automated and I would watch how the computer handled it. It took me a while-and actual flight training-to recognize the value of trim and stable thrust during approach. After a while I could focus on my sight picture, including VASI/PAPI lights, and give my gauges a regular and consistent scan with my attention focused squarely on how the approach 'felt' as a whole. If you are having trouble with landings automate the whole thing for a while in practice sessions. Try different weather settings and times of day, and don't be afraid to disengage AP from time to time to see if you can maintain the approach. I am much better at landing in real flight than FSX, which has to do with depth perception more than anything, but I have gotten much better over the years this way and am no longer petrified of arriving at an airport where a visual approach is called for. Let me know if you try this and how it works. I'm curious to see...

[David Vega]

Here's a good article on landing jets. Note the point about positive landings are preferred over the smooth greasers of propeller aircraft.

Dave Vega
sax702

[airifr]

Mostly important is being stabilized, you can have all parameters correct if not stabilized landing will suffer, be it at 1000ft. Positive landings are necessary depending on conditions, short runways, gusty conditions etc..
Smooth landings and positive landings are two different techniques although similar.

[airifr]

Mostly important is being stabilized, you can have all parameters correct if not stabilized landing will suffer, be it at 1000ft. Positive landings are necessary depending on conditions, short runways, gusty conditions etc..
Smooth landings and positive landings are two different techniques although similar.

Forgot to mention, a smooth landing will have under 100fpm and a positive landing will have between 200 and 300fpm, anything over 300fpm is excessive. We can't land an aircraft at 400fpm and say "I made a positive landing", no.