I was always taught that a any landing you can walk away from is a good one. Seriously though, it comes down to many factors including weather, managing energy and  timing of the flare. Don't obsess over the rate of descent. A safe landing is more important than a smooth landing. 

2 hours ago, clayton4115 said:

what would be a good landing in fpm for a CJ4?

I don't know how to answer that.  I mean, "it depends" is the best answer.

Often fpm isn't a very good way to classify a "good" landing in a jet.   Sometimes, like at KMDW or MHTG, you may need to plop down the aircraft in a hurry.  It's not a smooth landing, but it's a GOOD landing because you aren't overrunning the runway.

This is not what to do

https://youtu.be/1xjJuWkSUGA

 

 

15 minutes ago, precog said:

This is not what to do

https://youtu.be/1xjJuWkSUGA

 

 

hahaha your right, but I shouldn't laugh I would probably do the same learning to fly!

A good landing is a very small number of FPM (flare).  What I expect you were asking about was approach FPM.

15 hours ago, Chock said:

Aircraft carrier jets and props are a bit different though. They are designed to come down really pretty hard because what that does is absorb a lot of the energy from flight as a downward impact rather than the aeroplane retaining a lot of forward motion. This makes the aeroplane easier to slow down with the arrestor wires. So it's not uncommon for a carrier jet fighter or similar to come down at 700 fpm because the thing is designed to take that kind of thing, although they might have to jettison external stores to be able to do this. You won't find most carrier landings being less than maybe 450 fpm, although what the oleos on most carrier aeroplanes do have, is a controlled release valve on them which slowly lets the compression off to prevent the aeroplane from bouncing back into the air.

While technically correct, the energy dissipation from a hard touch down is negligible when it comes to slowing an aircraft in the forward direction. Little of the energy from the y axis translates to the x axis. 

The larger reason for the high descent rates on a carrier trap come from safety and reproducibility.

Hitting a small touchdown area is much more reliable from a stable flight attitude than hitting that same point during a transiting attitude. You also spend more time in ground effect with a flare, as if the carriers burble wasn’t enough to deal with for variability.  

As for safety, and assuming an identical touchdown point, a flare adds a segment of a shallower descent. This effectively lowers your “threshold” height compared to a standard approach to the same touchdown point at a fixed glide slope angle. In this case, the threshold is clearance at the ramp. And you want that to be healthy to avoid ramp strikes. 

In fact, to maintain ramp clearance in high wind over the deck scenarios, the IFOLS glide path angle is increased. Higher headwinds slow the ground speed on approach, which with a moving runway means a long travel over the group for the same height…effectively making a more shallow approach angle. 
 

And if that isn’t enough, the IFOLS heigh is adjusted per aircraft to maintain a safe ramp clearance. Each aircraft has set hook/eye distance.  It’s the vertical distance from the pilots eyes to the hook at landing AOA. It only varies by a few feet from each aircraft, but the importance of ramp clearance is such that this too is adjusted. 
 

There’s a lot of work that goes in to making sure the tail hook (which is the lowest part of the aircraft) crosses the ramp at the same heigh every time. If I recall the number correctly, it’s 13.1’ from the ramp to the hook on a perfect approach. 

27 minutes ago, fppilot said:

A good landing is a very small number of FPM (flare).  What I expect you were asking about was approach FPM.

Now I'm confused.  I don't want to step on your toes, as you have an aviation background, but approach FPM is in exact relation to approach speed.  There is no good or bad, as a glideslope, or ideal approach, is at a fixed angle.  The higher your approach speed, the higher the descent rate necessary to hold that angle.  An aircraft following a 3 degree glideslope travelling at 100 kts is going to have a lower descent rate than an aircraft travelling at 200 kts.  There is an optimum descent rate for any given speed to hold that glideslope angle, or adversely, a given speed to hold a descent rate.  He specifically asked about landing, which is a whole different ballgame to descent rate at approach, which is speed dependent.

4 minutes ago, Sigwolf said:

Now I'm confused.  I don't want to step on your toes, as you have an aviation background, but approach FPM is in exact relation to approach speed.  There is no good or bad, as a glideslope, or ideal approach, is at a fixed angle.  The higher your approach speed, the higher the descent rate necessary to hold that angle.  An aircraft following a 3 degree glideslope travelling at 100 kts is going to have a lower descent rate than an aircraft travelling at 200 kts.  There is an optimum descent rate for any given speed to hold that glideslope angle, or adversely, a given speed to hold a descent rate.  He specifically asked about landing, which is a whole different ballgame to descent rate at approach, which is speed dependent.

I believe you are overthinking this.  I recommend you abandon theory and go to a local airport and at least hitch a ride with a GA pilot and observe.

1 minute ago, fppilot said:

I believe you are overthinking this.  I recommend you abandon theory and go to a local airport and at least hitch a ride with a GA pilot and observe.

Seriously?  I hold a commercial license with a former CFIIMEL, and a retired ATCS.  I tried to be nice to someone in the industry, and you decide to throw out that line?

9 minutes ago, Sigwolf said:

Seriously?  I hold a commercial license with a former CFIIMEL, and a retired ATCS.  I tried to be nice to someone in the industry, and you decide to throw out that line?

Then I seriously do not recognize where you were coming from.  If you truly have the credentials you represent then why in the world would you have gotten so theoretical and technical?   You would be fully trained and versed in the question, and it is not rocket science.  Configuration and speed.

Edited August 18, 20214 yr by fppilot

1 minute ago, fppilot said:

Then I seriously do not recognize where you were coming from.  If you truly have the credentials you represent then why in the world would you have asked your question?  You would be fully trained and versed in the question you asked.

I am, which is *why* the question was asked.  Because it would not make sense that you would assume the OP was asking something completely contrary to what he said.  I do find it very funny that you think that you should be the gatekeeper to my credentials.  I earned those... your opinion of them really doesn't matter.

6 minutes ago, Sigwolf said:

I am, which is *why* the question was asked.  Because it would not make sense that you would assume the OP was asking something completely contrary to what he said.  I do find it very funny that you think that you should be the gatekeeper to my credentials.  I earned those... your opinion of them really doesn't matter.

My comment was to the point that you were being too technical and theoretical for the discussion. Approach speed and flaring is just not that complicated! 

11 minutes ago, fppilot said:

My comment was to the point that you were being too technical and theoretical for the discussion. Approach speed and flaring is just not that complicated! 

And my point was that you were conflating different subjects.  Approach speed *is* technical and is directly related to descent rate.  It doesn't need to be complicated, just follow the recommended speeds for the aircraft flown and you will achieve the desired rate.  Flaring, on the other hand, is an art, and different aircraft will require different application of that art. 😄

 

edit..  I may, or may not, have had a few less adept students in that art that prompted my career change to ATC, not to mention the early 90's hiring deficit in the airlines.  Happily, a good number of my former students have stayed the course, and are successful airline pilots today, though most have them have faced layoffs and furloughs over the years.  Aviation is a difficult, but usually rewarding career path.

Edited August 18, 20214 yr by Sigwolf
clarification

1 hour ago, Sigwolf said:

Now I'm confused.  I don't want to step on your toes, as you have an aviation background, but approach FPM is in exact relation to approach speed.  There is no good or bad, as a glideslope, or ideal approach, is at a fixed angle.  The higher your approach speed, the higher the descent rate necessary to hold that angle.  An aircraft following a 3 degree glideslope travelling at 100 kts is going to have a lower descent rate than an aircraft travelling at 200 kts.  There is an optimum descent rate for any given speed to hold that glideslope angle, or adversely, a given speed to hold a descent rate.  He specifically asked about landing, which is a whole different ballgame to descent rate at approach, which is speed dependent.

 

This is a very good point for airliners and other heavy aircraft that conform to a stabilised 3 degree approach. The situation with GA is not quite so simple.

Regardless, I do agree that the original discussion was about fpm at touchdown after flare, not fpm during approach.

 

4 minutes ago, Glenn Fitzpatrick said:

 

This is a very good point for airliners and other heavy aircraft that conform to a stabilised 3 degree approach. The situation with GA is not quite so simple.

Regardless, I do agree that the original discussion was about fpm at touchdown after flare, not fpm during approach.

 

Funny thing is, it's just as simple.  I can't count the number of times students of mine said, "I can't understand why I came in so high, I was trying to descend." as they came in at 85+ kts in a C172.  The next time around they fly the approach at 65 kts and everything comes together.  Trim and throttle control are obviously important, but nailing the ideal airspeed for a given aircraft makes an approach so much easier, and correspondingly, makes the transition to flare easier, as well.  The best landings generally are a result of a nice, stabilized, approach.  You can certainly make a smooth landing from a lousy approach, but you have to work a whole lot harder.