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Aspen, Colorado Canadair crash

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  • #16
    Originally posted by Gabriel View Post
    The maximum demonstrated crosswind is the max crosswind that the manufacutrer demonstrated during certification. It's not a limitation. And hence, it cannot be violated.

    That said, it is usually considered a good practice not to attempt to do what test pilots didn't attempt themselves.

    Good night.
    ok, so you too are advocating that pilots violate what's written in the manuals of their aircraft? these maximums, "demonstrated" or otherwise, are part of the operating manuals of the respective aircraft. i guarantee the manufacturer put them there for a good reason.

    in the thread on pprune, there are several comments that are relevant: just because you can get away with doing something that doesn't comport with the requirements doesn't mean you should.

    you may live to tell the story about how you landed in violation of requirements. and the aircraft may very well be capable of operating in far more severe conditions than the manufacturer lists. but the bottom line is this: bust requirements and the crash is your fault.

    these jokers destroyed a $30 million ++ aircraft and caused one person to die (not sure if it was a crew member or not). if they had simply diverted nothing would have happened except some rich folk would've been a little inconvenienced.

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    • #17
      Originally posted by TeeVee View Post
      ok, so you too are advocating that pilots violate what's written in the manuals of their aircraft? these maximums, "demonstrated" or otherwise, are part of the operating manuals of the respective aircraft. i guarantee the manufacturer put them there for a good reason.

      in the thread on pprune, there are several comments that are relevant: just because you can get away with doing something that doesn't comport with the requirements doesn't mean you should.

      you may live to tell the story about how you landed in violation of requirements. and the aircraft may very well be capable of operating in far more severe conditions than the manufacturer lists. but the bottom line is this: bust requirements and the crash is your fault.

      these jokers destroyed a $30 million ++ aircraft and caused one person to die (not sure if it was a crew member or not). if they had simply diverted nothing would have happened except some rich folk would've been a little inconvenienced.
      C'mon Mr. Lawyer- interpret this correctly and stop putting words in our mouths.

      Who advocated disregarding the maximum demonstrated crosswind?

      It his however, a fact that the maximum demonstrated cross wind component is likely less than the maximum capapble cross wind component.

      Think about that for a second- how in the hell do you test that the engineer calculated maximum crosswind component is accurate or not...

      If they calculate 30 knots, and you find a measured 30 knot wind but it happens to 31 knots- you're probably screwed...

      So, all you've got is the actual crosswind when you are testing the plane.

      Then you have a number that means nothing...and has no legal meaning.

      It's just a figure, not a violation.

      Now, as to the subject of good judgement- and the requirements to use it...like I said, I'm thinking as a Lawyer you know a lot about that.

      No one said that exceeding the demonstrated crosswind was a good thing to do...we just said that it was not illegal.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #18
        Originally posted by TeeVee View Post
        ok, so you too are advocating that pilots violate what's written in the manuals of their aircraft?
        No. Why? Does it look so?

        these maximums, "demonstrated" or otherwise, are part of the operating manuals of the respective aircraft.
        Not everything that is written in the operating manual is a requirement or a limitation.

        For example, the manual of the Piper Tomahawk recommends to rotate with 60 knots to improve the controlability of the plane in the event of an engine failure during take-off.

        But the take of performance charts (where you compute things like take-off distance) say "rotate with 52 kts". This part is mandatory. You are required to use the available means to ensure that you have enough runway to take-off, and you have no means to calculate the take-off distance with a rotation speed of 60 knots. That said, if the chart for 52 knots shows a take-off tun of 1200ft and you have 3000ft available, the "pilot judgement" is considered an acceptable mean to estblish that you have enough runway even if you rotate at 60 knots.

        So why did they use 52kts instead of 60, if they recomend 60?
        Because it was the lowest speed that complied with the requirements and that they could use in test flights to perform consistent take-offs. In other words, it's the one that gives shortest take-off runs with consistency.

        i guarantee the manufacturer put them there for a good reason.
        Because they are required to.

        in the thread on pprune, there are several comments that are relevant: just because you can get away with doing something that doesn't comport with the requirements doesn't mean you should.
        I fully agree with that.

        you may live to tell the story about how you landed in violation of requirements. and the aircraft may very well be capable of operating in far more severe conditions than the manufacturer lists. but the bottom line is this: bust requirements and the crash is your fault.
        Again, the max demonstrated crosswind is not a requirement.
        The manufacturer can establish crosswind and tailwind limitations. And the operator can establish stricter ones (or ones at all if the manfucaturer didn't establish them). And the manual is full of other limitations and requirements (wight, CG, flap speeds, max turbulence speed, never-exceed speed, max load in the cargo compartment, approved maneuvers, max RPM, acceptable fuel types, acceptable oil types, minimum oil level, etc, etc, etc... But the max demonstrated crosswind is NOT one of them.

        That doesn't mean that it is wise to land with more than the demonstrated crosswind. It's also not wise to fly in hail, even when the Tomahawk manual says nothing about it.

        But... you didn't catch 3WE's trap: The max demonstrated CROSSWIND is NOT a LIMITATION, but it doesn't mean thet there isn't a max landing TAILWIND LIMITATION that they might have violated.

        --- 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 ---

        Comment


        • #19
          Comments by pilots on flying into Aspen

          J. Mac McClellan is known through the flying world as the long-time editor of Flying magazine.  Now he has a regular column for the EAA, the Experimental Aircraft Association. He sent a message about this weekend's fatal crash at Aspen, when a private jet landed with strong and gusty tailwinds (as mentioned here).


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          • #20
            It's one thing to land with a slightly-higher-than-legal tailwind on say Rwy 26 at ABQ (all 15,000' of it) or 31L at JFK or 28R or C at ORD, it's quite another to land with 20kt too much tailwind in a place like ASE.

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            • #21
              It is interesting to note, however, that apparently this plane didn't run off the end of the runway, but rather it veered off runway.

              --- 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 ---

              Comment


              • #22
                Originally posted by Gabriel View Post
                It is interesting to note, however, that apparently this plane didn't run off the end of the runway, but rather it veered off runway.
                That was my point several posts ago.

                Now, to pull unsubstantiated, speculative, parlour theories from between my Mark IV dual-sensor bioaccelerometers...

                Does it seem plausable that they were trying to swerve laterally to avoid running off the end (See Airport 1975)?

                That doesn't seem too plausible to me (I mean to totally bust a wing off, flip over, crash and burn....pretty extreme....).

                Then again, someone forcibly executing a 35,000 ft stall isn't very plausible either.
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • #23
                  you guys crack me up! if we were talking about an overspeed situation where a wing broke off, i doubt either of you would be bullshitting about theoretical maximums, demonstrated maximums and some super secret squirrel "real maximums." how do you determine as a lowly pilot, which "maximums" are real and which are "demonstrated" so therefore ok to bust???

                  so, um, hey, the manual says this aircraft requires full flaps for landing. maybe we should try landing with no flaps to see if it can do it?

                  so um hey, the manual says maximum service ceiling is 40k'. let's break the record since i'm sure it can hit 42k' with no problem. what's another 2k?

                  so um hey says here in fine print that max takeoff weight at current sea level and temp is x. i know we're at x++ but shit man, this puppy's got some serious engines back there so let's go for it!

                  i mean, manuals are more like guidelines anyway, right? sorta like the pirates' code...

                  Comment


                  • #24
                    Originally posted by TeeVee View Post
                    you guys crack me up! if we were talking about an overspeed situation where a wing broke off, i doubt either of you would be bullshitting about theoretical maximums, demonstrated maximums and some super secret squirrel "real maximums." how do you determine as a lowly pilot, which "maximums" are real and which are "demonstrated"...
                    You read the manual. If it's listed as a limitation, you are not allowed to violate it. If it's not a limitation, you can't violate it even if you exceed it.
                    ... so therefore ok to bust???
                    In my opinion, it's not ok to bust the max demonstrated landing corsswind, so I don't.

                    so, um, hey, the manual says this aircraft requires full flaps for landing. maybe we should try landing with no flaps to see if it can do it?
                    If the manual says that that full flaps is required, then you must comply with it. But the manual doesn't say so for the max demonstrated crosswind.

                    so um hey says here in fine print that max takeoff weight at current sea level and temp is x. i know we're at x++ but shit man, this puppy's got some serious engines back there so let's go for it!
                    Unlike the max demonstrated crosswind, the weight and balance limitations are, well, limitations.

                    i mean, manuals are more like guidelines anyway, right? sorta like the pirates' code...
                    Both things. Manual have parts that are mandatory and parts that are guidelines. If the manufacturer wants or feels the need to put a limitation in the max crosswind (or whatever wind) they are absolutely free to do it, and that would be, well, a limitation and hence mandatory. But if they stay short of that by just informing what was the maximum crosswind that the test pilots actually demonstrated during the certification (it's an FAR requirement to include this data in the manual), that is not a limitation.

                    If the manual says list as a limitation that the max acceptable crosswind is 20 kts and the pilot knowingly lands in conditions that exceed this limit, the pilot can face administrative action that could end with his licence revoked (even if there was no accident). If the manual just states the demonstrated crosswind and the pilot exceeds this non-limitation, even if there is an accident the FAA can take no action against the pilot for "violating" a non-limitation that, as such, can't be violated, even if there is an accident (although the FAA has a wildcard that can use whenever they didn't like what the pilot do: careless and reckless flying, but they can't just say "you violated this limitation" as in the previous case).

                    I can't believe that this is so difficult to understand for a lawyer.

                    --- 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 ---

                    Comment


                    • #25
                      not hard to understand at all.

                      scroll to the eleventh page...



                      p.s. i wasn;t the one that started talking about "demonstrated" anything. and i don't believe that word was used in any reports to date.

                      Comment


                      • #26
                        I think we have a problem of semantics. 'Maximum' traditionally refers to the greatest thing possible, and that implies that it is a limit. Maximum Demonstrated Crosswind Component should really be referred to as Greatest Demonstrated Crosswind Component. But 'maximum' has become a casually misused term in the modern lexicon and so has become a confused and subjective adjective. In any case, I'm sure everything Gabriel tells us on the subject is as good as gold.

                        Comment


                        • #27
                          Originally posted by TeeVee View Post
                          not hard to understand at all.

                          scroll to the eleventh page...
                          http://www.google.com/url?sa=t&rct=j...59026428,d.cWc
                          3. OPERATING LIMITATIONS

                          [...]

                          E. TAILWIND CONDITIONS
                          The maximum tail wind component approved for take-off and landing is 10 knots.


                          That's a limitation and hence it's mandatory and violating it can lead to administrative action.

                          p.s. i wasn;t the one that started talking about "demonstrated" anything. and i don't believe that word was used in any reports to date.
                          I know and I have been repeatedly telling you so. Haven't you been reading my posts? Let me show you one example:

                          Originally posted by Gabriel, some posts ago
                          But... you didn't catch 3WE's trap: The max DEMONSTRATED CROSSWIND is NOT a LIMITATION, but that doesn't mean that there isn't a max landing TAILWIND LIMITATION that they might have violated.

                          --- 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 ---

                          Comment


                          • #28
                            i always read your posts. my point the whole time was that they busted the manual, and this more than likely led to the crash.

                            Comment


                            • #29
                              Originally posted by TeeVee View Post
                              my point the whole time was that they busted the manual, and this more than likely led to the crash.
                              I know that this was your point from the beginning:

                              Originally posted by TeeVee
                              sad but it sounds like a case of impatient pilots. my buddy that flies a challenger says max tailwind is 10 knots, so these poor slobs exceeded the manual by a factor of more than 3.
                              But then 3WE hijacked the thread (and said he was doing so) with a lateral argument and you (we) hung to it:

                              Originally posted by 3WE
                              So there's a statement worthy of a thread hijack.

                              There's some pretty interesting fine print on "the maximum demonstrated crosswind component"...

                              ...including the fact that one may make a legal landing in a higher crosswind.
                              You were talking about illegally exceeding a max tailwind limitation, and 3WE was talking about legally exceeding a demonstrated crosswind. And both of you were right all the time.

                              --- 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 ---

                              Comment


                              • #30
                                Originally posted by TeeVee View Post
                                there's a reason the manufacturer assigns a maximum cross and tail wind and i'm sure they're not arbitrary.
                                Has the manufacturer assigned a non-arbitrary maximum crosswind for this aircraft?
                                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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