Many times in a jet I’ve pulled the buckets just to slow down the taxi. A jet is a different animal than a Bonanza in that you’ve a whole lot of thrust pushing all the time. I don’t think the SF has bucket.

I don't think any of the Williams-powered jets have TRs.

Which other jets are Williams powered (without TRs)? Do they have lots of runway overruns?

No prop. 85kts will help, but it in this case a jet and a prop plane are very different.

Yes, using the brakes HARD and a DRY LEVEL PAVED runway.

Now land the Eclipse on a wet runway. What is the runway usage then?

How about glare ice? What is the runway usage then?

The Bonanza will stop since it lacks residual thrust.

The SETP/TTP will stop easily since they have beta.

The jet? Different animal.

This is why someone might prefer an M500 over an SF50, if they have need to land on runways that aren't always dry.

You will never see a jet "bush" plane, but you will see turboprop bush planes all the time.

Mike C.

The jet has thrust, but the prop has drag.

Landing a twin with one feathered requires significantly more runway if you just roll out.

No Williams powered jet uses TRs.

However, early Williams applications that lacked FADEC (CJ, CJ1, CJ2 for example), used "thrust attenuators" which are paddles canted into the exhaust stream. They didn't "reverse", but they cut down on the idle thrust.

https://www.youtube.com/watch?v=qS_1Ui48N3w

With FADECs, idle thrust became less and the TAs were removed. Non FADEC fuel controllers have to keep idle thrust safely above bog down levels for all density altitudes, temperatures, winds, etc, so they have much higher idle thrust. A FADEC can computationally compensate for all the variables and maintains the engine RPM at a lower but controlled speed.

I've seen estimates that the ground idle thrust on a FADEC equipped FJ33/44 engine is about 50 pounds. That is like a rope tied to the front of the plane with a constant 50 lbs pull.

The older JT15D engines were about 200 pounds. So a Citation II, for example, would have 400 pounds pulling on it at idle.


Runway overruns are the signature accident for jets.

It is hard to find a light jet without a runway overrun.

Here is an eye opening chart from a CJ2+ showing the various adders for runway conditions.

Example:

Dry: 2800 ft
Wet: 4150 ft
1/8" standing water: 6300 ft
1/8" slush: 6400 ft
1" snow: 5800 ft
compacted snow: 4000 ft
wet ice: 16,400 ft (!!)

So whether you can get into your airport may change if it RAINED.

Mike C.

Yes. Wet ice is the game stopper. Most other conditions can be handled with adequate runway.

In the 550, a 1/4” of slush or water is a max limitation iirc.

Mike, you seem to want to state the obvious, and for some reason, state it over and over again as if it is really a revelation.

Of course jets are different from props. Duh.

Here's one way you haven't stated: Jets have a substantially lower accident rate than turboprops--a fraction of the fatal accident rate, and *way* less than the MU2--notwithstanding the higher possibility of overrun.

Ken

It is to some. How a Bonanza lands doesn't teach us much about a jet.


You have missed the numerous times I have said that.

But since you want it repeated, here is what I wrote on May 30th, 2016:

"The GA jet safety record is about 10 times better than turboprops."

Mike C.

You thought I would go back and look at what you wrote 2 *years* ago? I have trouble wading through what you write in 2 days!

Mike, I'm sorry, but I can't always read the volumes you post, so help me out please: what's your point? Is it that the SF50 is bad and won't sell? It looks to me like it is selling, and a lot of people seem to think it's pretty good.

Ken

Then you aren't qualified to say what I have or have not written, so you should avoid making such statements.

Mike C.

It would be much more interesting to see the fatal record of single pilot owner flown biz jets versus single pilot owner flown SETP's. Part 91 pro-flown and part 135 pro-flown usually with 2 pilots comprise the vast majority of biz jet flight hours and heavily skew the data. To think a single pilot flying 150 hours per year as a jet owner operator will enjoy the safety benefit of a 2 pilot pro-flown biz jet is a little silly. There have been quite a few owner flown single pilot fatals in biz jets in the last few years. WE have seen fatals in the Eclipse, Mustang, P100, and several Citations. Hour for hour, not sure there really is a difference in single pilot SETP and single pilot biz jet owner operators, especially matched for mission. In fact the turbine accidents all have the same thing in common. The pilots usually killed a perfectly good plane. That is because for the most part, turbines aircraft rarely completely fail. In fact with more pilots stepping up into biz jets as the prices come down, I expect the accident rate to increase.

It would be much more interesting to see the fatal record of single pilot owner flown biz jets versus single pilot owner flown SETP's. Part 91 pro-flown and part 135 pro-flown usually with 2 pilots comprise the vast majority of biz jet flight hours and heavily skew the data. To think a single pilot flying 150 hours per year as a jet owner operator will enjoy the safety benefit of a 2 pilot pro-flown biz jet is a little silly. There have been quite a few owner flown single pilot fatals in biz jets in the last few years. WE have seen fatals in the Eclipse, Mustang, P100, and several Citations. Hour for hour, not sure there really is a difference in single pilot SETP and single pilot biz jet owner operators, especially matched for mission. In fact the turbine accidents all have the same thing in common. The pilots usually killed a perfectly good plane. That is because for the most part, turbines aircraft rarely completely fail. In fact with more pilots stepping up into biz jets as the prices come down, I expect the accident rate to increase.