BeechTalk - BT

Username Protected · **Posted:** 27 Jan 2015, 00:32

Username Protected wrote:

CJ's AFM Limitation section says "Takeoffs and landings are limited to paved runway surfaces.".

How short a field can you operate from? At sea level.

Username Protected · **Posted:** 27 Jan 2015, 00:42

Username Protected wrote:

Depends which CJ, weight, OAT, and winds.

CJ2+ at 8500 lbs, -25C, 30 kt headwind = 1520'

12,500 MGW, 20C, 0 wind = 3420'

In general 4000' is always good. 3000' can be doable at lighter weight or some headwind.

These are balanced field length accelerate to V1 and stop distances. Actual runway used during normal takeoff can be 50% to 60% of that but those distances are not published.

Was thinking of your CJ2+ since you're familiar. We have a few CJs operate in and out of our airport (KSQL, 2600' at sea level). I know one is a CJ4, it's actually based here. I have seen CJ1s on occasion, and I *think* 2s or maybe 3s, I haven't studied them enough to tell just by looking.

The -25C case doesn't come up that much around here.

Username Protected · **Posted:** 27 Jan 2015, 00:55

Username Protected wrote:

Was thinking of your CJ2+ since you're familiar. We have a few CJs operate in and out of our airport (KSQL, 2600' at sea level). I know one is a CJ4, it's actually based here. I have seen CJ1s on occasion, and I *think* 2s or maybe 3s, I haven't studied them enough to tell just by looking.

The -25C case doesn't come up that much around here.

Really depends on their weight in operating off of SQL. CJ3 and CJ4 need less runway for the same weight then CJ2 because they have more powerful engines and their BEW isn't much more then the 2.

Cessna has an iPad App and you can put in airport, runway, current conditions and it tells you max weight for takeoff.

Username Protected · **Posted:** 27 Jan 2015, 00:59

Username Protected wrote:

Actual runway used during normal takeoff can be 50% to 60% of that but those distances are not published.

It isn't exactly clear to me why a turboprop is allowed to operate at a runway for which it can't stop if an engine fails at precisely the wrong time, but a jet isn't. Seems arbitrary.

To put it another way, if I was willing to have no accel stop capability in a turboprop, then I would be willing to do that in a jet, too. If anything, the jet is less likely to have an engine failure in the first place.

Mike C.

Username Protected · **Posted:** 27 Jan 2015, 01:01

Username Protected wrote:

We have a few CJs operate in and out of our airport (KSQL, 2600' at sea level). I know one is a CJ4, it's actually based here. I have seen CJ1s on occasion, and I *think* 2s or maybe 3s, I haven't studied them enough to tell just by looking.

And they ALL met balanced field, right?

Sure....

Mike C.

Username Protected · **Posted:** 27 Jan 2015, 01:04

Username Protected wrote:

It isn't exactly clear to me why a turboprop is allowed to operate at a runway for which it can't stop if an engine fails at precisely the wrong time, but a jet isn't. Seems arbitrary.

It is arbitrary to some degree. Gotta draw lines somewhere. I suspect there's a history in the time where jets had much longer takeoff rolls and faster takeoff speeds.

But even so, at present Jets under 6000lb (i.e. Eclipse) dont' need balanced field. And don't turboprops of some size/certification need balanced field. Can you operate a part 25 turboprop part 91 without a balanced field? (DO-328, Saab 2000, etc)

Username Protected · **Posted:** 27 Jan 2015, 01:08

Username Protected wrote:

Actual runway used during normal takeoff can be 50% to 60% of that but those distances are not published.

It isn't exactly clear to me why a turboprop is allowed to operate at a runway for which it can't stop if an engine fails at precisely the wrong time, but a jet isn't. Seems arbitrary.

To put it another way, if I was willing to have no accel stop capability in a turboprop, then I would be willing to do that in a jet, too. If anything, the jet is less likely to have an engine failure in the first place.

Mike C.

Username Protected · **Posted:** 27 Jan 2015, 01:08

FAR 23 vs FAR 25, different set of certification rules. Normal versus Transport. Perfectly legal for you to takeoff in your turboprop lose an engine and plow into a neighborhood being FAR 23. Not legal for Southwest to do the same being FAR 25. Higher level of safety. You can derive all of the same info from the performance section, few do.

If turboprops had to have a Balanced Field Length, nobody would buy them.

Username Protected · **Posted:** 27 Jan 2015, 01:12

Username Protected wrote:

Can you operate a part 25 turboprop part 91 without a balanced field? (DO-328, Saab 2000, etc)

Show me what the AFM says about takeoff limitations and computations.

Username Protected · **Posted:** 27 Jan 2015, 01:15

Under part 23 a climb gradient on one engine is required if the airplane has a GTOW of 6000# or more. (commuter category)

Merlins, Mitsubishis and Conquests will climb at close to 1000FPM on one engine at GTOW.

Username Protected · **Posted:** 27 Jan 2015, 01:15

IDK about a FAR 25 Turboprop, but you can fly a FAR 23 "Commuter" Category KA 350 without a balanced field. Meaning you don't have to have the 115%(I can't remember if it's 115 or 130) of the all engine TO distance. You do have to have the TO distance and Accel/Stop though.

Username Protected · **Posted:** 27 Jan 2015, 01:16

Username Protected wrote:

Under part 23 a climb gradient on one engine is required if the airplane has a GTOW of 6000# or more.

Where is this stated? Certification or everyday? Not following.

Username Protected · **Posted:** 27 Jan 2015, 01:18

Username Protected wrote:

Under part 23 a climb gradient on one engine is required if the airplane has a GTOW of 6000# or more.

Where is this stated? Certification or everyday? Not following.

Username Protected · **Posted:** 27 Jan 2015, 01:19

So, you are saying that a King Air at MTOW has to climb? Absolutely not true. On one engine of course.

Username Protected · **Posted:** 27 Jan 2015, 01:21

The Merlin I flew did have balanced field data in the manual. Accelerate stop is rarely the limiting factor in a turboprop so if you have accelerate go performance you're probably balanced.

Best jet to replace MU2