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Lear 35 down approaching Teterboro

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  • #16
    Originally posted by Evan View Post
    Can you shed some light on how this circle to land is done here from the RWY 06 ILS? The only ILS 06 to visual 01 approach I can find involves breaking off the ILS in a right bank and then turning LEFT to final over Giant's Stadium. But, if I'm getting this right, the Lear was making a hard RIGHT turn to final when it lost control. Does that involve breaking off ILS and cycling right turns back to 01? That seems illogical to me.
    Yes, the normal and logical circling from 06 to 01 seems to be first right and then left. But that should be started at 5 miles out, not 0.5 miles out. Starting the circling so short would require much more significant turns (in the same directions as said before). Maybe the stall happened during the first right turn. I initially thought that they overshot the runway during the left turn so they had to ter left more than the RWY heading to come back and then make a right turn to align, but it seems that the accident happened much earlier in the process. The tower does report a steep left bank and the nose going down, which would be compatible with a turn to final.

    In any event, it still seems to be a garden variety of stall-spin-crash-burn-die while maneuvering in the pattern (or in the circling in this case).

    --- 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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    • #17
      Originally posted by Gabriel View Post
      The tower does report a steep left bank and the nose going down, which would be compatible with a turn to final.
      The way I read that, the left bank was probably unintentional, the result of an asymmetric stall. I can't recall where the right turn was first stated as a turn to final (maybe that was your assumption?) but I tend to think the alleged stall happened when turning right, off the localizer... very late and very steep. I guess aerobatics, tailwind gusts and wingtip tanks don't mix.

      Still, would that be considered a 'circle to land' approach? Seems more like... shuffle to land...

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      • #18
        Originally posted by Evan View Post
        Still, would that be considered a 'circle to land' approach? Seems more like... shuffle to land...
        http://155.178.201.160/d-tpp/1706/00890IL6.PDF

        Technicalities...when you land on a runway OTHER than the one the ILS is for, it is generally termed 'circle to land'....and generally, you can 'circle around' all over creation to whatever runway you need...I believe the major rule is to maintain visual contact with the airport, along with some basic altitude rules.

        Based on Gabe's flying article and the 'eyewitness accounts' of extreme banks, I now disagree with Gabe (that it's the ole subtle cramped turn to final with speed decay and visual speed misinterpretation), but more like gross deviation from the good FUNDAMENTAL practice of don't bank the hell out of the plane when down low (or if you are doing anything close to commercial flight).

        Sure, the winds may have contributed a bit, but if they were really banked as steep (or roughly as steep) as what the tower reported...someone had really bad tunnel vision, or were doing Evan's default of Cowboy disregard for fundamentals and procedure, both...

        Pure speculation- I think Gabe may be out of line that the turn needed to be 5 miles out...not sure that's Kosher in the New Yark crowded airspace with airports all over creation...BUT, indeed they waited too long...I was disappointed that Flying did not mention visibility or ceiling- as conceivably, that might force a guy to push it...delays in breaking out and seeing the airport and/or concerns with losing contact while 'circling'.
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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        • #19
          Originally posted by 3WE View Post
          Pure speculation- I think Gabe may be out of line that the turn needed to be 5 miles out...not sure that's Kosher in the New Yark crowded airspace with airports all over creation...BUT, indeed they waited too long...I was disappointed that Flying did not mention visibility or ceiling- as conceivably, that might force a guy to push it...delays in breaking out and seeing the airport and/or concerns with losing contact while 'circling'.
          I always thought a 'circle to land' needed a downwing leg.

          Anyway...

          In a reasonably executed circle to land, I believe that Lear would need a circling radius of about 1.5 miles. Breaking off the ILS at 2 miles out, that seems unlikely to put you on the TDZ of RWY 1.

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          • #20
            Originally posted by Evan View Post
            I always thought a 'circle to land' needed a downwing leg.
            Indeed the term is inspired by a single-runway situation where you shoot the ILS, break out, and circle back around 180 degrees to land in the opposite direction (which actually is maybe more of a teardrop and not a circle)

            That said, with lots of runway configurations and the concept that you fly the ILS to get under the clouds and then land on a different runway results in the "circling minimums" that exist on typical approaches. http://155.178.201.160/d-tpp/1706/00890IL6.PDF

            Circle, teardrop, side-step, shuffle, and Lord knows what other gyrations might be used to land elsewhere...Yeah, it's insider jargon that conflicts with common, "Webster Dictionary" meanings, but is more efficient than "Maneuvering-for-another-runway minimums." Maybe you'd like 'MFARMS', better, but you may have to do more than post in this forum to get the industry to address it.

            So maybe break it off at 3 miles, then. Plus, I wonder if there might be issues with flying over the stadium?
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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            • #21
              Originally posted by 3WE View Post
              Pure speculation- I think Gabe may be out of line that the turn needed to be 5 miles out...not sure that's Kosher in the New Yark crowded airspace with airports all over creation...BUT, indeed they waited too long...I was disappointed that Flying did not mention visibility or ceiling- as conceivably, that might force a guy to push it...delays in breaking out and seeing the airport and/or concerns with losing contact while 'circling'.
              What?

              The Runway 6 ILS, circle to Runway 1 is a common approach to TEB, with aircraft normally leaving the localizer at the final approach fix nearly four miles from the end of the runway. In the May 15 accident, the Learjet remained on the localizer until less than a mile from the end of Runway 6 before starting a right turn to land on Runway 1.
              At the time of the accident, winds were reported as 320 at 20 knots gusting to 30, a few scattered clouds at 4,500 feet and visibility of more than 10 miles.
              Guess where that comes from?

              --- 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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              • #22
                Orange and blue lines are 1 NM long. Green turns are 1NM radius. It assumes no wind.
                Typical descent path is about 300 to 350 ft per NM.
                With a plane that approaches at more than 100 kts, there's no way I am braking off the LOC 06 any closer than 4NM.
                Click image for larger version

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                --- 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
                  Originally posted by Gabriel View Post
                  Orange and blue lines are 1 NM long. Green turns are 1NM radius. It assumes no wind.
                  Typical descent path is about 300 to 350 ft per NM.
                  With a plane that approaches at more than 100 kts, there's no way I am braking off the LOC 06 any closer than 4NM.
                  [ATTACH=CONFIG]7746[/ATTACH]
                  What's the turning radius of a Lear 35 at approach speed in a 90* bank?

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                  • #24
                    Originally posted by Evan View Post
                    What's the turning radius of a Lear 35 at approach speed in a 90* bank?
                    130 kts is 67 m/s.
                    At 90 deg of bank you will not hold the altitude or attitude no matter how much you "pull up" (because "up" is 100% horizontal), but that doesn't prevent you from making the turn, and all the lift will contribute to the radial acceleration needed to bend the speed vector (i.e. turn).
                    So let's say that you pull with a load factor of 2.5, that means that the lift will be 2.5 times the weight, and since the lift will be the only horizontal force with a radial component (neglecting an radial component that the thrust may have), we have

                    Sum of F radial = 2.5 x weight = m x acc radial
                    Since weight = m x g (g = acceleration of the gravity =~ 10 m/s2)
                    2.5 x m x g = m x a
                    So, a = 2.5 g = 25 m/s2

                    Now, in a circular motion, a = V2/r, so r = V2/a = (67 m/s)2 / 25 m/s2 = 179 m = 0.1 NM

                    How much with a 30 deg bank turn, assuming we hold the vertical speed constant?

                    Well, the vertical component of the lift needs to be equal to the weight.
                    The lift vector, tilted 30 degrees from the vertical, will need to measure weight / cos 30 deg.

                    1/cos 30 = 1.15 will be the load factor (and, if you are interested, the stall speed will be sqrt(1.15) = 1.075 times, or 7.5% faster than, the 1G stall speed). But we are not interested in anything of this.

                    The horizontal component of the lift, the one that will make the plane turn, will be lift x sin 30, and since lift was = weight / cos 30, we get that the horizontal component will be weight / cos 30 x sin 30 and that's weight x tan 30 = 0.58 times weight (and remember that weight = m x g).

                    Horizontal force = horizontal component of the lift = 0.58 x m x g = m x a
                    a = 0.58 g

                    a = v2/r

                    r = v2/a = (67 m/s)2 / 0.58x10 m/s2 = 773 m or 0.42 NM

                    At 15 deg bank it would be 0.9 NM.

                    --- 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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                    • #25
                      Originally posted by Evan View Post
                      What's the turning radius of a Lear 35 at approach speed in a 90* bank?
                      Do you mean in the horizontal plane, or the vertical?
                      Be alert! America needs more lerts.

                      Eric Law

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                      • #26
                        Originally posted by elaw View Post
                        Do you mean in the horizontal plane, or the vertical?
                        What's the climbing radius of a Lear 35 in a 90* bank? I guess its an ever tightening... spiral...

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                        • #27
                          Originally posted by Gabriel View Post
                          ...Guess where that comes from?...4 miles...
                          LOL- it's beautiful making half-donkey-ass-hat posts after a very quick scan of the flying article, and having Gabe do the deep dive read. I owe you a beer- on my second scan of the article, I did not see ceiling and visibility.

                          Seeing that ceiling / visibility is a non issue...I also see that I was right that 5 miles was a bit much since 4 miles is standard...

                          OK, good...I get it...the 4 miles (to me) seems like a fat, dumb and happy figure. I am pretty sure I have seen a 3 mile-or-so, near-90-degree base-to-final turn while riding an MD-80, heading West and then South into KKCI...nice gentle bank...plenty of time to straighten it out on final...speed under control...solid airmanship. (Yeah, sure, my foffie side imagined them running a wingtip into the ground...but the reality was Fat, Dumb, Happy, Stabilized).

                          So, the guy broke it off 1 mile out...I concur that is too tight. I do still stand by my 'gross deviation from really fundamental fundamentals'...So, maybe it's 1) Don't bank the hell out of a jet (especially down low), and 2) Fast planes will get ahead of you if you are behind. I can't totally discount the wind, but what...without the wind, they would have only needed an 85-degree bank?
                          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                          • #28
                            Originally posted by Gabriel View Post

                            r = v2/a = (67 m/s)2 / 0.58x10 m/s2 = 773 m or 0.42 NM
                            Ok, so, one mile out... .42NM radius turn to the right... .42NM radius turn to the left... nothing a self-respecting cowboy in a hotrod 35 can't handle...

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                            • #29
                              Originally posted by Evan View Post
                              What's the turning radius of a Lear 35 at approach speed in a 90* bank?
                              Depends upon how much you pull up relentlessly and how far above maneuvering speed you are.
                              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                              • #30
                                Originally posted by Evan View Post
                                Ok, so, one mile out... .42NM radius turn to the right... .42NM radius turn to the left... nothing a self-respecting cowboy in a hotrod 35 can't handle...
                                Cowboys knew their stuff and they were bold and daring but not suicidal. They may try to ride a brave bull in a rodeo, but they would not stay standing in front of a stampede of bulls.

                                If this pilot intentionally attempted a say 60 deg bank turn at approach speed and 500 ft, "cowboy" is not the word I'd use. I may use it if he attempted an aileron roll after staying in a shallow climb after take off to gain enough airspeed.

                                --- 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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