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  • #46
    ​Colombian investigators have determined that the crew of a Boeing 727-200 freighter departed in a tailwind before the aircraft overran and struck a perimeter fence, briefly becoming airborne before crashing in a field.


    Colombian investigators have determined that the crew of a Boeing 727-200 freighter departed in a tailwind before the aircraft overran and struck a perimeter fence, briefly becoming airborne before crashing in a field.

    The inquiry into the 20 December accident at Puerto Carreno states that the crew was apparently “unaware” of information regarding the direction and strength of the wind.

    Colombian accident investigation authority GRIAA says preliminary information shows two aircraft – an Embraer 170 and a Cessna 208 – took off from runway 07 shortly before the 727 was due to depart.

    These two aircraft had taken into account the prevailing wind at the airport, it says. Meteorological data showed the wind from 10° at 8kt, which would have favoured a take-off from 07.

    But GRIAA says cockpit-voice recorder information shows the 727 headed instead to the threshold of the opposite-direction runway 25. It points out that Puerto Carreno was operating as an uncontrolled airport from 15:00, and the 727 departed at around 17:20.

    Flight-data recorder information indicates that the trijet was configured with 30° take-off flaps. The inquiry associates this setting with a modification known as the ‘Quiet Wing’ which was developed for the 727 in order to reduce noise.

    The ‘Quiet Wing’ system is designed to increase take-off performance through modifications including a flap and aileron droop, to increase lift and thereby cut perceived noise on the ground.

    GRIAA adds that the 727’s configuration also included 6.5 units of elevator trim.

    The inquiry says the evidence suggests the crew was not aware of the wind situation. Departing from runway 25 under the recorded wind conditions would have resulted in a 4kt tailwind component rather than a 4kt headwind.

    GRIAA says the air temperature was 31C. The airport has an elevation of 54m and a runway length of 1,800m.

    All three engines were functioning during the take-off roll. The investigators state that the aircraft’s V1 and rotation speeds were 127kt.

    Evidence from video images of the ill-fated departure show the aircraft overran and hit a perimeter fence – tearing out a 13m-wide section – before striking a small military structure and a tree, which sheared off the right main landing-gear and the starboard inboard flap.

    Cockpit-voice recorder information shows the crew determined that the starboard engine had lost thrust and there was a loss hydraulic fluid following the impact.

    The 727 managed to climb to 790ft but entered a slow turn to the right, with its bank angle gradually increasing to 60°. It remained airborne for around 2min but its airspeed bled away, the resulting loss of lift caused the aircraft to lose height, and it struck the ground about 4nm from the threshold of runway 07.

    GRIAA says ground-proximity alerts and stall warnings had been sounding in the cockpit, and the crew was carrying out a fuel-jettison procedure.

    The jet struck the ground at a large angle of bank, it states, with high horizontal speed but relatively shallow pitch.

    One of the six occupants of the freighter survived the crash. The cockpit and empennage were among the main components to emerge from the debris field.

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    • #47


      So let's get this straight: The only reason why an airplane that should have been able to achieve 35 ft over the departure end of the runway after loosing an engine at V1, didn't loose any engine and achieved 0 ft over the departure end of he runway and maybe 10 ft maybe a couple hundred feet beyond the end of the runway, was because of a 4kts tailwind that was not accounted for.

      Sure. I totally buy it.

      --- 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


      • #48
        Originally posted by Gabriel
        ***an airplane that should have been able to achieve 35 ft over the departure end of the runway after loosing an engine at V1***
        I thought we had ample historic YouTube video evidence that the plane generally crossed the fence at ~10 feet with 3 engines operating.

        THAT might be affected by the tailwind...

        BUT

        Shall we infer that the cowboys generally operated without the safety margin you reference?
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • #49
          Originally posted by 3WE View Post
          I thought we had ample historic YouTube video evidence that the plane generally crossed the fence at ~10 feet with 3 engines operating.

          THAT might be affected by the tailwind...
          Ok, but then the problem is not the unaccounted 4-knots tailwind.

          --- 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


          • #50
            Originally posted by Gabriel View Post
            Ok, but then the problem is not the unaccounted 4-knots tailwind.
            I don't think the report is saying that 'the problem' was the tailwind. I think they are saying it was the last straw that removed any margin for error. What it isn't telling us is what the error was (or errors were).

            The moral of the story is 'always plan with an ample margin for error'.

            What about those 30* t/o flaps.. Is that even legal on passenger flights? Leaving one of them on a fence would create a lot of sudden asymmetric lift and drag. I wonder if they tried to retract the remaining flaps. They probably had no situational awareness but it seems like a pretty good instinctive reaction to sustained uncommanded roll that doesn't respond to aileron. Could that have saved them?

            Comment


            • #51
              Originally posted by Evan View Post
              ***What about those 30* t/o flaps.. Is that even legal on passenger flights?***
              You really have no grasp of fundamentals.

              I'm betting that's in the book for shorter field takeoffs...and totally appropriate. Right on the typical edge of where you start gaining 'more drag than lift'...

              You should instinctively grab for the flaps if there's an uncommanded roll?

              What, is that cowboy improvisation? Is that in the FCOM somewhere.
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

              Comment


              • #52
                Originally posted by 3WE View Post
                You really have no grasp of fundamentals.
                Well, what little grasp I have tells me that's a lot of drag on takeoff. And a potential for disaster if a flap asymmetry occurs at low altitude (See: this thread).

                You should instinctively grab for the flaps if there's an uncommanded roll?

                What, is that cowboy improvisation? Is that in the FCOM somewhere.
                I don't think there is an FCOM procedure for hitting a fence and ripping off the starboard flaps... but I'll check.

                Comment


                • #53
                  Originally posted by Evan View Post
                  Well, what little grasp I have tells me that's a lot of drag on takeoff. And a potential for disaster if a flap assymetry occurs at low altitude (See: this thread).
                  I can't quote specific numbers but my sense is that plowing into trees/buildings/etc. because you don't gain any (or enough) altitude by the time you reach the end of the runway creates even more drag.

                  And the reality is that during that phase of flight, there's the potential for disaster if any one of a thousand things happens. That's why planes are designed to not break much, and why all sorts of training and special procedures are applied to that phase of flight.
                  Be alert! America needs more lerts.

                  Eric Law

                  Comment


                  • #54
                    Originally posted by elaw View Post
                    I can't quote specific numbers but my sense is that plowing into trees/buildings/etc. because you don't gain any (or enough) altitude by the time you reach the end of the runway creates even more drag.
                    Just use the drag equation: D = 1/2 * d * V^2 * Cd * S
                    Just replace d with the density of the tree/building/fence.

                    --- 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


                    • #55
                      Originally posted by 3WE View Post
                      I'm betting that's in the book for shorter field takeoffs...and totally appropriate. Right on the typical edge of where you start gaining 'more drag than lift'...
                      Flaps aren't about gaining lift, they're about allowing the plane to fly at slower speeds. You might think going to flaps 30 would be a good idea on a short runway with obstacles on the extended centerline (get off the runway sooner and sacrifice climb-out performance until flap retraction speed), but there are three problems with that. 1) Flaps 30 isn't lowering your Vr by very much over flaps 20 (if at all), 2) it is giving you a significant drag penalty in the process (as landing flaps are designed to do) and, 3) it almost certainly prevents the plane from complying with the requirements of 14 CFR Part 25 Section 121 Climb: Single Engine Inoperative. Especially for that last reason, I would expect this to be illegal at least on passenger flights. The forth, hidden danger I see is in the unlikely event of a flap asymmetry, as was seen here, the effect will be more pronounced and perhaps unrecoverable...

                      Comment


                      • #56
                        Originally posted by Gabriel View Post


                        So let's get this straight: The only reason why an airplane that should have been able to achieve 35 ft over the departure end of the runway after loosing an engine at V1, didn't loose any engine and achieved 0 ft over the departure end of he runway and maybe 10 ft maybe a couple hundred feet beyond the end of the runway, was because of a 4kts tailwind that was not accounted for.

                        Sure. I totally buy it.
                        Yeah, they didn't really follow the 5 why's method of retrospective analysis did they?

                        I think I also read somewhere that the crew never filed a proper cargo manifest AND they only listed 5 occupants of the plane when it turned out there were 6, 4 in the cockpit who died instantly. 2 survived the initial crash but one died en route to hospital.

                        Video, teilen, Kamerahandy, Videohandy, kostenlos, hochladen


                        Looking at this video of the same aircraft on another day, I would say the net 8kt was the LAST deciding factor. All I can say is that the videographer was lucky on the day he took that one. Even in this video they don't clear that shack by much.

                        Comment


                        • #57
                          Originally posted by Evan View Post
                          Flaps aren't about gaining lift, they're about allowing the plane to fly at slower speeds. You might think going to flaps 30 would be a good idea on a short runway with obstacles on the extended centerline (get off the runway sooner and sacrifice climb-out performance until flap retraction speed), but there are three problems with that. 1) Flaps 30 isn't lowering your Vr by very much over flaps 20 (if at all), 2) it is giving you a significant drag penalty in the process (as landing flaps are designed to do) and, 3) it almost certainly prevents the plane from complying with the requirements of 14 CFR Part 25 Section 121 Climb: Single Engine Inoperative. Especially for that last reason, I would expect this to be illegal at least on passenger flights. The forth, hidden danger I see is in the unlikely event of a flap asymmetry, as was seen here, the effect will be more pronounced and perhaps unrecoverable...
                          Hi Evan,

                          The flaps allow the plane to fly at lower speeds by trading off lift for forward drag. At the same airspeed, more flap = more lift and more drag. Less flap means less lift and less drag.

                          Comment


                          • #58
                            ​Investigators probing the crash of an Aerosucre Boeing 727-200 freighter during departure have so far been unable to determine the take-off weight of the aircraft.


                            Investigators probing the crash of an Aerosucre Boeing 727-200 freighter during departure have so far been unable to determine the take-off weight of the aircraft.

                            The 727 overran at Puerto Carreno as it attempted to depart the airport in a tailwind, Colombian accident investigation authority GRIAA has found.

                            But it has been unable to locate details of the manifest or the aircraft’s weight and balance during examination of the wreckage.

                            GRIAA adds that there was no copy of this information in the company’s offices.

                            The inquiry estimates that the aircraft, bound for Bogota, was transporting nine pallets containing 19,820lb – just under 9,000kg – of cargo, taking this assumption from the chartering company’s documents.

                            As the 727 conducted its take-off roll, it overran and struck the perimeter fence, as well as other obstacles, which badly damaged the jet. It became airborne for a short time before crashing in a field and being consumed by fire.

                            The flightplan submitted by Aerosucre, provided to the inquiry by the air traffic service of Puerto Carreno, listed five occupants on board the jet, although six were located at the crash site – five crew members and a cargo specialist.

                            Two of the six survived the initial impact but one succumbed to injuries while being transferred to hospital.

                            The captain of the aircraft had accumulated over 8,700h including more than 6,800h on type. The first officerhad nearly 3,300h on type.

                            GRIAA says the aircraft had previously arrived at Puerto Carreno from Bogota, carrying a load of perishable and miscellaneous freight weighing 20,423lb and some 31,500lb of fuel.

                            Comment


                            • #59
                              More articles.



                              It seems the jet was operating at the extreme edge of its envelope—or beyond it, in the case of yesterday’s crash. With no margin for contingencies, even small non-technical issues such as changing atmospheric conditions or minor miscalculations in weight and balance and air density could prove deadly during a short-field departure.

                              Comment


                              • #60
                                Originally posted by Evan View Post
                                Flaps aren't about gaining lift, they're about allowing the plane to fly at slower speeds. You might think going to flaps 30 would be a good idea on a short runway with obstacles on the extended centerline (get off the runway sooner and sacrifice climb-out performance until flap retraction speed), but there are three problems with that. 1) Flaps 30 isn't lowering your Vr by very much over flaps 20 (if at all), 2) it is giving you a significant drag penalty in the process (as landing flaps are designed to do) and, 3) it almost certainly prevents the plane from complying with the requirements of 14 CFR Part 25 Section 121 Climb: Single Engine Inoperative. Especially for that last reason, I would expect this to be illegal at least on passenger flights. The forth, hidden danger I see is in the unlikely event of a flap asymmetry, as was seen here, the effect will be more pronounced and perhaps unrecoverable...
                                I don't know all the details and could not find much in the Internet, but...
                                - The original preliminary accident report in Spanish, in page 4, said that the plane was configured with Falps 30deg and 6.5 units of trim. And it has a callout for footnote 7 which reads: "30deg: Position of the flaps, according to the modification STC ST00507SE "Flaps & Aileron Droop Modification - Quiet Wing Corporation".
                                - http://www.aerocivil.gov.co/autorida...%20-%20PUB.pdf
                                - That STC is available in Quiet Wing's web site, but is just basic regulatory information with no clear description of what the mod is about. It does mention "Incorporating in the flap system a DuganAir Technology, Inc. modified drum cam" and "Incorporating changes in the flaps and aileron positions and rigging (Flap and Aileron Droop modification". Oddly, it also includes "Incorporating winglets" which this plane clearly didn't have. I don't know if that was optional in the mood or what.
                                - Mind you, STC ST00507SE is approved by the FAA, and I am sure that it incorporates changes in the flight manual too to account for any procedural difference and performance difference.
                                - http://quietwing.com/PDF/B727-200.St....ST00507SE.pdf

                                --- 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

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