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  • #31
    Originally posted by Evan View Post
    How does that 1.67 factor sync with a lack of ground spoilers and/or brakes? Does it still leave a good margin?
    Your question is clearly sarcastic (the alternative would be that it's stupid).

    Do you know what happens if you use full brakes and full reverser in one engine but the spoilers don't extend and you leave forward thrust in the other engine? An A320 burns in a building across the avenue.

    When you land in a contaminated runway, you calculate the landing distance taking into account the contaminated runway, applying the margins stated before and then multiplying by another 1.15. Except that the regs in this case let (or used to let, not sute if they removed it) take into account the reversers if their application can be proven to be reliable. Do you know what happens when the pilot fails to engage the reliable reversers? They squash a boy inside a car just out of Midway.

    And what do you want to show with that photo? That the plane achieved taxi speed 250m / 750ft short of the other plane doesn't mean that the pilot could have not stopped shorter if needed. It is possible (not saying that it happened) that, once it was clear that the plane would stop with runway to spare behind the other plane, the pilot didn't keep applying maximum braking/spoilers/reversers.

    And of course, if the spoilers failed and that made the plane not able to stop behind the other one, that doesn't mean that the pilots would just sit there watching the show. There is steering which can be provided with the nosewheel, the rudder, differential braking and differential thrust. I am sure the pilots will choose to end in the grass rather than in foreign aluminum.

    And remember it is me the one here criticizing this pilot the most for not going around. But you asked "with what margin" and I just replied.

    Never mind the margins, never mind if the other plane was 2000 ft farther down the runway, this pilot should have gone around, unless he really thought that they were likely to die if they didn't, which I doubt. And even then, he should have advised ATC that he was landing depite the instruction to go around. Again, one word: unable. Then ATC could have ordered the plane stopped on the runway to get the hell out of there (or, more likely, the pilots of that plane would have done that by themselves when they heard the other pilot saying "unable").

    --- 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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    • #32
      Originally posted by 3WE View Post
      Yeah...I'm just not getting what the deal is...While I know that helicopters don't really like true vertical departures- and that speed is their friend too, with all the safety concerns and other procedures that go on, you'd think there'd be some way to climb out and stay the hell out of the way of the fixed wing aircraft????
      That's easily fixed. All helicopter traffic at a large airport with extensive fixed wing operations should only be allowed to operate parallel to or away from the active runway/s.
      If it 'ain't broken........ Don't try to mend it !

      Comment


      • #33
        I don't understand what the obsession with the helicopter is.

        It was a 'run of the mill' misunderstood callsign issue. They thought they heard a takeoff clearance, most likely read it back at the same time the aircraft did, and they departed.

        It could have been another aircraft, a different runway, any number of things. Don't get worked up over the fact it was a heli.

        With what margins? Does that allow for ground spoiler failure (and failure to deploy them manually), brake failure or reverser failure? Does it allow for a margin of pilot error, a bit of float? Does it allow for the unexpected?
        Gabriel has answered this one well. Calculated landing distance is calculated landing distance, regardless of what the obstacle is, be it a stationary aircraft, a LAHSO procedure, a lake, or a brick wall. It matters not whether you hit a stationary aircraft or a kindergarten at the end of the runway.

        I understand why the current SOP is to stop and stabilze on the runway. What I am questioning is if the risks that are addressed in doing that are outweigh the risks presented in this (repeatable) scenario. Being stopped on an active runway knowing an aircraft behind you was on short final would make me want to at least steer it slowly off onto the high-speed turnout.
        Absolutely not. If you're on the runway, it is your runway. The aircraft behind should be conducting a go around. Most crews would want to get off the runway ASAP, but why would you exit a runway when a controller has told you stop (a VERY rare occurrence), and you don't have a clue why? This has all happened very quickly - I'm sure if ATC had time to tell them to vacate, they would have.

        One word could have solved it:

        - XYZ go around.
        - Unable.
        How high were they at the time? Did they have time to communicate?

        Out of interest Gabriel in your flying experience have you been in the circuit area with another aircraft, that you know you are close to but you don't know where he is? In a light aircraft at a towered aerodrome I had another aircraft flying the circuit at the same time as me, reporting the same positions at the same time - the tower only had me visual, and not the other aircraft. Its the scariest moment I've ever had in aviation. Conducting a go around with known conflicting, but unsighted, traffic would be very unpleasant.

        I have to agree with Gabriel
        And probably me too - I'm not saying that, sitting here now, landing was the safest option. I'm not saying that you should never go around in this scenario. I'm simply trying to explain that the situation is no-where near as cut and dried as this thread was making it out to be. There is a valid counter position that says that landing, when you know the obstacle is more than your certified landing distance away, is not necessarily unsafe, and going around when there is known, but not sighted, traffic in your go around path is not necessarily the safest course of action.

        The rule books are written with a huge caveat in them for exactly this type of scenario. The PIC has to make an assessment, with very little time, of the safest course of action to take, and he is given that latitude.

        Comment


        • #34
          Originally posted by MCM View Post
          I don't understand what the obsession with the helicopter is.
          Obsession is too hard of a word.

          It's that:

          1) Helicopters EASILY COULD avoid the landing and departing flight paths to essentially never be a traffic conflict even if there's a missed radio call or controller screw up or whatever reason.

          2) At a lot of airports, helicopters ALREADY DO avoid the landing and departing flight paths.

          So why not here?
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • #35
            Originally posted by MCM View Post
            There is a valid counter position that says that landing, when you know the obstacle is more than your certified landing distance away, is not necessarily unsafe, and going around when there is known, but not sighted, traffic in your go around path is not necessarily the safest course of action.
            MCM, this is my only point of contention. To say something is not necessarily unsafe is not adequate justification to go through with it when a safer alternative exists. Aviation safety has to rely on near-certainties by including margins for the unexpected. For example, spoilers do fail to deploy and then pilots do fail to deploy them manually. If this had happened the landing would have been deemed reckless in hindsight. For this reason it should have been deemed reckless in foresight. You have to always consider margins when making that PIC assessment. "Yes, I can do it, provided that..."
            Originally posted by MCM View Post
            The rule books are written with a huge caveat in them for exactly this type of scenario. The PIC has to make an assessment, with very little time, of the safest course of action to take, and he is given that latitude.
            Sure, if the go-around is deemed an even riskier path, that is justification to take the lesser path of risk and continue. But how can that be here? The pilots must have had a visual on the helicopter. My concern here is that the landing was continued out of a reckless sense of confidence and a neglect for consideration of the potential for error or failure. And that confidence is at the heart of so many disasters: the failure to recognize hidden dangers.

            Comment


            • #36
              MCM, I agree with you. It's just that the scenario that would justify the land decision seems so "perfect storm" to me that, by now, I tend to think that it is more likely that the pilot made a big mistake (to use kind words).

              - The taking-off plane is told to stop and they do. They don't vacate the runway, perhaps because they didn't knew why they were told to stop in the first place. Perhaps the helicopter and the plane read back the take-off clearance at the same time and hence nobody heard any of them.

              - The landing plane hears that the taking-off plane is told to stop and that themselves are told to go-around.

              At this point your scenario requires that the pilot of the landing plane knows that there is a conflicting traffic but doesn't know where it is (so it was not in sight). But if it was not in sight, why would they think that they had a conflicting traffic in the first place?

              And then, that they were so close to touchdown that they didn't have time to move one inch the thumb and press the PTT button to say "unable".

              Possible? Yes. Anything not impossible is possible. But if that was the scenario, landing was not only a valid option but perhaps the best one.

              I will keep skeptically waiting for the final report.

              And yes, it happened to me, binf in the traffic pattern looking for another plane that was supposed to be (and sometimes actually was) in the same general place than myself. But my most scary situation (mid-air related) was seeing a Cessna 182 fly by in front of me and fly through their wake 1 second later. I didn't have time to do anything, not even to scare, and the fear came only in the immediate hindsight. We were in controlled airspace ant the 182 called the ATC only after our near-hit. Anyway, I should have seen him. Both of us failed at "see and avoid".

              --- 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


              • #37
                Originally posted by Evan View Post
                Aviation safety has to rely on near-certainties by including margins for the unexpected.
                Still wouldn't be safer than staying home, even taking into account the possibility of that big old oak tree falling squarely on your bedroom.

                Comment


                • #38
                  Originally posted by MCM View Post
                  I don't understand what the obsession with the helicopter is.
                  It's either that or they'll obsess over tail #s...

                  Comment


                  • #39
                    Originally posted by 3WE View Post
                    Obsession is too hard of a word.

                    It's that:

                    1) Helicopters EASILY COULD avoid the landing and departing flight paths to essentially never be a traffic conflict even if there's a missed radio call or controller screw up or whatever reason.

                    2) At a lot of airports, helicopters ALREADY DO avoid the landing and departing flight paths.

                    So why not here?
                    Well, there is dispute regarding what;s the best way to treat helicopters.

                    In Argentina, helicopters operating in airports are just another aircraft (which technically they are) and follow the same taxi, take-off, SID, STAR, approach and landing procedures than the airplanes, unless told or authorized otherwise by ATC (the difference is that in the landing and taxiing they don't touch the ground ).

                    I think that's a good solution. Less variation = less possibility of mistakes, misinterpretation, etc.

                    --- 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


                    • #40
                      Originally posted by Gabriel View Post
                      At this point your scenario requires that the pilot of the landing plane knows that there is a conflicting traffic but doesn't know where it is (so it was not in sight). But if it was not in sight, why would they think that they had a conflicting traffic in the first place?
                      Is this not in sight?

                      Comment


                      • #41
                        Originally posted by ATLcrew View Post
                        Still wouldn't be safer than staying home, even taking into account the possibility of that big old oak tree falling squarely on your bedroom.
                        Excellent use of mindless devil's advocacy, Bravo.

                        You don't land on a runway unless you are nearly-certain that there it is clear and safe to do so. That is why we have minima. I didn't make that up.

                        Comment


                        • #42
                          Originally posted by Evan View Post
                          Is this not in sight?
                          Depending on whether they saw it or not. Look what I told of my close encounter. We both were within the sight capability of each other but none of us had the other in sight.

                          --- 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


                          • #43
                            Originally posted by Gabriel View Post
                            Well, there is dispute regarding what;s the best way to treat helicopters.

                            In Argentina, helicopters operating in airports are just another aircraft (which technically they are) and follow the same taxi, take-off, SID, STAR, approach and landing procedures than the airplanes, unless told or authorized otherwise by ATC (the difference is that in the landing and taxiing they don't touch the ground ).

                            I think that's a good solution. Less variation = less possibility of mistakes, misinterpretation, etc.
                            But the Mark IV passive 300-800 nm RADAR is extremely powerful when there's no water nor 5000 miles of granite to obscure the interrogation beam...

                            ...and is routinely used to reduce the full IMC separations and safely improve operational efficiency- regardless of whether the wings whirl or slice straight ahead.

                            Given that helicopters have much more maneuverability, it seems very workable for the vast majority of the time to keep the hell away from the runway until you have 1000 ft of vertical separation from where the airplanes are and then cross paths!
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                            Comment


                            • #44
                              'Sight and Avoid' is used in very limited circumstances in jet operations to reduce separation as you suggest - but it is done only after the aircraft concerned confirms having sighted the aircraft. A lot of pilots will reject such a clearance unless its extremely obvious (such as the SFO parallel approaches).

                              Is this not in sight?
                              NO

                              The landing aircraft isn't looking in the missed approach path - both pilots are watching the runway, the instruments, and things in a generally downward perspective.

                              Just because the helicopter is physically sightable doesn't mean that it has been sighted.

                              Sighting and avoiding another aircraft, particularly one the size of a helicopter which is unpredictable in its movements is very difficult. They could have known it was there as they may have heard the readback of the helicopter rather than the readback of the departing aeroplane, depending on transmitter/receiver location, followed by the stop instruction.

                              Again, this is just a hypothetical. The Captain may have just decided 'what the hell' and landed anyway. But there is another Skywalker.

                              You don't land on a runway unless you are nearly-certain that there it is clear and safe to do so.
                              If you have assessed your landing distance, and there is no obstacle within that landing distance, is that not 'nearly-certain' that it is 'clear and safe to do so'?

                              No, I'm not advocating landing on occupied runways. But if I'm allowed to land on a runway with a ravine just off the end of the runway which is exactly the length of my landing distance, and that is considered safe, then landing behind an obstacle on the runway (which could be a displaced threshold due to runway works) isn't inherently unsafe.

                              There's plenty of occasions that we don't take the safest course of action, but one that has been risk assessed as safe enough. You are correct that this safety assessment is one done away from the aircraft, when there is time to 'brainstorm' and 'work the problem' with flow charts and whiteboards. But similarly, Captains are employed to make these decisions on their own every now and again when the 'un-workshopped' problem arises - its just the way it has to work.

                              Comment


                              • #45
                                See my signature?

                                It actually happened to me...(and it really wasn't that big of a deal.)

                                A control tower saw fit to ask a 172 to get the hell off the runway (and no fault of mine) so some other small aircraft that mis judged his base turn could go ahead and land (probably some hot shot doctor hauling a$$ in his V-tail Bonanza- too proud to power back and trim nose-up on the way in.)

                                Yet, there's two airliners loaded with numerous souls, in a somewhat similar scenario, and the tower's not asking the landed dude to expedite off the runway?
                                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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