Exit rules for PAC 750?

[skyjumpenfool 2]

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The rest of the discussion seems to be more about stalls.

We have had a really good track record with the one we own at Raeford FWIW.

I posted a Pic of a pac stall that clearely showed a jumper thrown toward the tail. So, yes, stalls and tail strikes can be related.

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=114506;

Since our last experience (1 1/2 years ago) we've not had any issues. Pilots are more aware and jumpers have been diligent, but, it only takes a short lapse in memory to create a problem.

A sign on the back wall might be a good reminder to all. Place it right next to the "No Farting" sticker.

Birdshit & Fools Productions

"Son, only two things fall from the sky."

[Fast 0]

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So maybe a good first rule of thumb to at least try out (since hopefully we're not going to start a designed experiment to test the edges of the envelope ):

1. No more than 1/3 the weight/number of jumpers outside the door (whichever is LESS)
2. Jumpers have to hug the fuselage

#1 might be mistake-proofed by making the step smaller, so that fewer people can reasonably fit outside.

#2 might be mistake-proofed by moving the bar above the door to where most people have to reach for it, so they naturally hold themselves tight.

Another option for #2 would be to get rid of the wonderful step that makes it so easy to hang a lot of jumpers out; that moves the air disruption to about 10" higher, which might improve the aerodynamics.

Regardless, while PACs seem to be a great plane for a DZ, they appear to have somewhat narrower operational limits than some other planes. If we operate within those limits, folks can continue to have fun in them. A couple of rules that can be written easily in the back of the airplane are more likely to be followed than "common knowledge," because common knowledge ain't always common.

Thoughts?

Wendy P.

Well, the step was made smaller. Don't know if many people remember what the step used to look like, but you could easily put 3 in the door and 2 on the camera step with the original step design. Then it got changed to the camera step just being that little nub on the back of the main step.

I think that people should be doing number 2 but I don't like the idea of moving the bar. It will make climb outs more difficult and it's not what people are expecting. Both things which would lead to string out jumpruns and such. The reality of it is that people need to just not be stupid. When someone shows up at a dropzone for the first time, someone needs to make sure they know the rules of the road.

~D
Where troubles melt like lemon drops Away above the chimney tops That's where you'll find me.
Swooping is taking one last poke at the bear before escaping it's cave - davelepka

[skyjumpenfool 2]

....... and somewhere along the road, PAC's will be redesigned to eliminate these (rather serious) issues? Right? Don't get me wrong, I love the PAC's. I just think a manufacturer designing a plane "specifically for skydiving" would want to improve their product.
IMH misguided O.

Birdshit & Fools Productions

"Son, only two things fall from the sky."

[lalapanz 0]

"I can count 10 stalls on jump-run in only a few years, and those are only the ones that get talked about online."

Name ten

[johnmatrix 21]

I jump from a PAC regularly and it is extremely easy to hit the tail.

I know I'm stating the obvious but you have to be very conscious of not jumping up at all on exit from the step. I've almost hit the tail when I thought I was pushing out (not up), I would not have realised if nobody had told me later.

[diablopilot 2]

I have more than 1000 exits from PAC's and if flown properly, there is little risk of a tail strike.

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You're not as good as you think you are. Seriously.

[skyjumpenfool 2]

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I have more than 1000 exits from PAC's and if flown properly, there is little risk of a tail strike.

There's that damn "if" word again.

Birdshit & Fools Productions

"Son, only two things fall from the sky."

[timmyfitz 0]

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I have more than 1000 exits from PAC's and if flown properly, there is little risk of a tail strike.

There's that damn "if" word again.

This statement should work better.

I have more than 1000 exits from [Insert type of aircraft] and if flown properly, there is little risk of a tail strike.

[diablopilot 2]

And I'll add I have seen an example of a stall and improper control/use of just about every modern jump plane in the US.

I have seen Tail strikes on Otters, King Airs, 99's, 182's, 206's, Caravan's.....

I have been in stalls in the same aircraft, plus a few....

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You're not as good as you think you are. Seriously.

[timmyfitz 0]

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And I'll add I have seen an example of a stall and improper control/use of just about every modern jump plane in the US.

I have seen Tail strikes on Otters, King Airs, 99's, 182's, 206's, Caravan's.....

I have been in stalls in the same aircraft, plus a few....

So what you are saying is

"I have seen [insert scenario] in a [insert type of aircraft] when things are not done properly.

or

I have seen tail strikes from [Insert type of aircraft] if the exit is not flown properly.

[diablopilot 2]

No I'm saying {insert comment here}.

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You're not as good as you think you are. Seriously.

[billvon 2,476]

>I have more than 1000 exits from PAC's and if flown properly, there is
>little risk of a tail strike.

Agreed. However, when pilots make errors, the PAC looks like it's a lot more susceptible to problems than other aircraft.

All aircraft are not the same.

[wmw999 2,178]

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when pilots make errors

Or when the jumpers make errors or don't communicate.

I think that jumpers don't necessarily know what an error is for this airplane. Establishing that would be good.

I can remember being in a DC3 with somewhere around 40 or more people in it once; we had a long runway and the people weren't large, so why not if we just cram way forward? I've been in a C182 with 5 jumpers and a pilot, with the same rationale. I've been in a Skyvan with a rafterload of people just sliding around on the floor. We put as many people as we could on the tail.

By and large, we don't do that any more, because it leaves too small a margin for things to go unexpectedly wrong. We have a fairly new airplane

It'd be good to have that knowledge for PACs be generally known, or marked on the airplane. That way it, too, would be just another airplane, rather than a topic of discussion like this.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[davelepka 4]

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All aircraft are not the same

Neither are all rigs, canopies, jumpsuits, helmets, or altimeters. If jumpers would learn how to properly use their equipment (to include aricraft), we wouldn't have these types of problems, or at least we would be able to more accurately identify aircraft that are truely not safe for jumping.

[billvon 2,476]

>Or when the jumpers make errors or don't communicate.

Very true. We've learned that lesson with Skyvans; now we're learning a similar lesson about PAC's.

[diablopilot 2]

There was a large amount of testing done above and beyond the testing required for the FAA when the PAC got to the US. They included stacking increasing amounts of weight in the back of the aircraft and flying different profiles. They and manufacturer testing showed the PAC has a much wider C of G range that any other jump plane, which is why it is so stable and can fly so slow. You can do 8 ways (9 w/video) all day long from the PAC, as long as you keep the airspeed at 80-85 kts. There-in lies the problem. Pilots get too comfortable flying too slow on jump run then they get caught behind the power curve. But the PAC is NOT more susceptible to stalls.

For the record, the PAC tail is 8” lower than a Caravan tail and 18” further aft. And on jump run, with flaps at 20, the tail is considerably high than a Caravan’s.

Here's an example of jumpers successfully using that aircraft as intended. http://www.youtube.com/watch?v=r3WJZ5gz1HE

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You're not as good as you think you are. Seriously.

[chuckakers 372]

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The nose began to climb and the pilot performed the stall prevention maneuver which assisted all the folks camping outside the plane with a safe departure.

Can you describe the " stall prevention maneuver"?

Chuck Akers
D-10855
Houston, TX

[diablopilot 2]

It's more of an "assisting the meat off the airplane" type maneuver. I believe it had a whole lot of rudder involved and "motivates" the airplane away from the jumpers unless they have super human strength.

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You're not as good as you think you are. Seriously.

[skyjumpenfool 2]

All the above is true! However, if you were an aircraft manufactuer, would you not want to improve future production runs of your product to make them better? That's why I said early in this thread..." I hope Pacific Air Corproation is reading this stuff". Imagine a PAC with a higher tail. A good jump ship would get even better!

Birdshit & Fools Productions

"Son, only two things fall from the sky."

[diablopilot 2]

Sure I would, and I'll bet it and other modifications have been considered. However, the act of "moving the tail" is not a simple task. It amounts to a near re-design and engineering of the entire aircraft and most certainly a re-certification of the aircraft.

No one is suggesting changes other jump aircraft, they are instead simply using them in the way they must in order to be successful as designed.

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You're not as good as you think you are. Seriously.

[davelepka 4]

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if you were an aircraft manufactuer, would you not want to improve future production runs of your product to make them better? That's why I said early in this thread..." I hope Pacific Air Corproation is reading this stuff". Imagine a PAC with a higher tail.

Probably not. Not in this case where operator error is causing the problem, and follwing some simple rules can eliminate the problem all together.

Moving the tail up is not an easy process. It would require recertification in the new position, and they're not selling enough of these to jumpers to cover that cost. They're not even selling enough to certify a plane in the first place, which is why they use the Cresco airframe as the starting point, it's already certified.

Think of the tail (elevator and rudder) as being attached to a lever arm (the fuselage) in order to move the wing into different attitudes. Any time you alter the size or position of the rudder, elevator, or fuselage, you change the mechanics of that lever arm.

Let's say you raise the elevator, and now it's in a differeent airstream than before. If it get's more airflow, then it would need a reduction in surface area to apply the same force to the airframe, or vice versa if it gets less airflow.

What effect will the higher elevator have on the rudder? Will it add or reduce airflow to the ridder? Would the rudder need an adjustment in size as well?

How about the airframe? Moving the elevator further up the vertical tail will require the tail to be reinforced. With the elevator routing it's forde down through the vertical tail, and down into the fuselage, it will need to be beefed up. How will the extra weight effect the useful load, or weight and balance calculations?

What about the elevator/elevator trim control cables? There's no longer a straight shot back to the elevator, so now all cables need to make a 90 degree turn to go up the tail, and another 90 to meet the new elevator. How do you design that system? What weight penalty will that bring on?

It's a real pain in the ass, and not something I can see as happeneding in response to the fact that jumpers can't communicate with a pilot, divers can't just wait forward of the door for their group to exit, and pilots can't keep the airspeed up on jumprun. Fixing those are easy. Moving the tail so everyone else can continue to act like a bonehead, not so easy.