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PA-28 crash in AR kills four

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  • #16
    Originally posted by guamainiac View Post
    Bump up a few pounds for the "jock effect" but as past prime, they would not carry the weight and mass so say 200 pounds for the men and 140 for the women?

    How does that put them weight wise?
    680 for the people and 300 or so for fuel with full tanks. We don't know what was in the baggage area, and we don't know who was seated where, except I think it's a safe assumption that the 81 year old pilot was in the front left seat. There could have been a balance issue, but I think you and Gabriel are both right that there was not a "hairy edge" situation regarding loading. I'm still thinking there was a fuel starvation issue (no fire in the crash) which would make the CG move aft with empty tanks, and present a very unstable aircraft with a failed engine. I guess we'll find out eventually.

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    • #17
      Great deduction. Sounds like it fits. Sad, but fits.
      Live, from a grassy knoll somewhere near you.

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      • #18
        Deadstick, one of the sobering reminders of the aging process came home back 20 years ago. I was buying a small cabin boat from a wonderful older fellow, he had purchased a smaller less capable boat and with the small boat he would be limited to the bays excluding any ocean use. Of course I asked why he was selling down and getting rid of what seemed to be a fine boat; out of ear shot his wife said that she insisted on the sale.

        On a holiday weekend and in a very, very heavy traffic at convergent channels that lead to the inlet (here in New Jersey), often shallow pathways to the ocean, I inquired about the dual battery system and how it was actuated. The old fellow just left the helm and began to walk to the rear of the boat to show me the manual throw over system. We were doing about 30 miles an hour (quick in a boat), in traffic and we sure didn't have an auto-pilot. There was no one steering. I got a few steps into following him when it hit me and I dove for the wheel.

        His wife later said, that is why she was forcing the sale. He goes out alone every day when I leave the house. One day he will be gone but at least we won't have as far to search. Sadly we lose the ability to know when to call it quits.
        Live, from a grassy knoll somewhere near you.

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        • #19
          Some years ago, I rented a PA-28-161 and flew it from Killeen, Texas to College Station, Texas to deliver some books for the library at the university in there, and decided to fill the rear compartment with books, probably 80 pounds of books, thanks God I was flying with my brother as passenger, the aircraft was flying with the nose up, probably 2 or 4 degrees nose up, but it was enough to alert me of the weird situation and told my brother to move to the back and remove those books from the rear compartment, and put them in the rear seats. I guess the CG or something changed as we consumed fuel.
          So my word of advise is not to put more than 10 pounds in the rear compartment.
          A Former Airdisaster.Com Forum (senior member)....

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          • #20
            Originally posted by AVION1 View Post
            Some years ago, I rented a PA-28-161 and flew it from Killeen, Texas to College Station, Texas to deliver some books for the library at the university in there, and decided to fill the rear compartment with books, probably 80 pounds of books, thanks God I was flying with my brother as passenger, the aircraft was flying with the nose up, probably 2 or 4 degrees nose up, but it was enough to alert me of the weird situation and told my brother to move to the back and remove those books from the rear compartment, and put them in the rear seats. I guess the CG or something changed as we consumed fuel.
            So my word of advise is not to put more than 10 pounds in the rear compartment.
            Quiz: Does the airplane flies more "tail haevy" (i.e. with a more nose-up attitude) when the CG is farther back?

            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
            --- Defend what you say with arguments, not by imposing your credentials ---

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            • #21
              My answer to that question is the aircraft requires more forward pressure on the control yoke/stick to maintain level flight. If that's what you mean by tail heavy.

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              • #22
                Originally posted by Deadstick View Post
                My answer to that question is the aircraft requires more forward pressure on the control yoke/stick to maintain level flight. If that's what you mean by tail heavy.
                No. As explained, I meant to ask with a more nose-up pitch attitude (compared with when the CG is in a more forward position). I was specifically addressing AVION1's comments:

                and decided to fill the rear compartment with [...] 80 pounds of books, thanks God I was flying with my brother as passenger, the aircraft was flying with the nose up, probably 2 or 4 degrees nose up, but it was enough to alert me of the weird situation and told my brother to move to the back and remove those books from the rear compartment, and put them in the rear seats.
                Anyway regarding your comment, that'd be the case if the pilot did not use the trim, which is hardly realistic. With the plane trimmed the stick force required to maintain level flight is zero regardless of the CG position. It's the trim which would be more nose-down than usual, but that would be hardly noticeable by the pilot.

                --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                --- Defend what you say with arguments, not by imposing your credentials ---

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                • #23
                  Well, of course you'd use the trim to neutralize the stick forces, but with an aft CG it would require more trim than in a balanced CG configuration.

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                  • #24
                    Originally posted by Deadstick View Post
                    Well, of course you'd use the trim to neutralize the stick forces, but with an aft CG it would require more trim than in a balanced CG configuration.
                    Exactly. But there is a not minor difference between one and the other.

                    My "hidden between lines" point is that in pilots' world there are a number of popular tales, many of which are wrong, and taking them for can be dangerous and even deadly. To name a few:

                    That stall is a matter of speed.
                    That an airplane turning from a headwind to a tailwind losses airspeed.
                    That you can't break an airplane due to aerodynamic loads if you fly below the maneuver speed.
                    And so on.

                    Two of them are:

                    "The plane flies in a more nose-up attitude with an aft CG"
                    False. We are used to see cars with a loaded trunk that run with "a nose up attitude", or boats that raise the bow when people moves aft.
                    But that's not the case with a flying airplane. At any one given speed, the wing must be flown at one given angle of attack to produce a lift equal to the weight, independently of the position of the CG. So the same pitch attitude is used to fly with a forward or an aft CG. And if one wanted to split hairs, as more load is transferred to the tail (with an aft CG), the tail will lift that is bigger (more upwards or less downwards) that it's usual share, leaving the wing with less lift to make to bear the remaining weight, so you need fly a little bit more nose-down with an aft CG than with a forward one.

                    "That a stick push force is required for level flight with an aft CG."
                    False, because the plane is trimmed to cancel stick forces. Of course, more nose-down trim will be required, but there is an important difference between the two: feedback. While the pilot wold clearly feel an unusual force on the stick, the unusual trim is very "transparent" to the pilot, because you don't make a force to hold the trim, the only feedback is the visual trim indicator, and the trim indicator is seldom used except before take-off (where, if the unusual aft CG condition is unknown to the pilot, he will put the trim in the unusual position).

                    Unfortunately, the cues that a plane gives for a dangerously aft CG are very subtle, and if the cues are big enough to be clearly detected, then it's probably too much aft and to late already for a corrective action. Thus the importance of a preemptive weight-and-balance assessment as part of the flight planning.

                    The bulk of the cues can be summarized as "the airplane flies funny", including, in order of appearance:
                    A slight nose-up attitude during taxi.
                    Hard to keep control while on-ground due to a light weight on the nose-wheel.
                    Early rotation or too light stick forces needed to rotate.
                    Airplane tends to pitch up after rotation.
                    During flight, little stick forces have more-than-expected effects on pitch (in both directions).
                    The plane doesn't want to keep the trimmed speed as well as usual.

                    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                    --- Defend what you say with arguments, not by imposing your credentials ---

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