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8407 - SOUTH AFRICAN CIVIL AVIATION AUTHORITY

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					                                                                                                       Ref. No: CA18/2/3/8407

                                                                                                            CA18/2/3/8407

                                      SOUTH AFRICAN CIVIL AVIATION AUTHORITY
                                             ACCIDENT REPORT – EXECUTIVE SUMMARY
         Aircraft Registration ZS-GND                Date of Accident     22 Dec 2007      Time of Accident      1330Z

         Type of Aircraft          Glider-Schleicher ASW 20A              Type of Operation       Private

         Pilot-in-command Licence Type               Glider               Age      34          Licence Valid     Yes

         Pilot-in-command Flying Experience                           155.98 (282
                                                     Total Flying Hours                  Hours on Type           33
                                                                      launches)
         Last Point of Departure                Hennenman Aerodrome, Free State Province

         Next Point of Intended Landing         Hennenman Aerodrome, Free State Province

         Location of the Accident Site with Reference to Easily Defined Geographical Points (GPS readings if
         possible)
         Approximately 3 nm south of Hennenman in a ploughed field, Free State Province
         (GPS co-ordinates: S28°03.234’ E027°02.203’)
         Meteorological Information Surface wind 045° at 5 kts, temperature 23°C, visibility >10 km, no cloud

         Number of People on Board         1+0           No. of People Injured    0           No. of People Killed     1

         Synopsis

         On 22 December 2007, two gliders were winch-launched at approximately 1140Z from Goldfields Gliding Club at
         Hennenman in the Free State. After they were launched, they headed in a south-westerly direction along the railway
         line to Virginia. After soaring in the same two thermals, they then separated overhead Virginia. The pilot of ZS-GND
         turned due east at Virginia and then headed in a north-easterly direction of 030° towards Ventersburg, east of
         Hennenman.

         According to the pilot of the second glider, the pilot of ZS-GND notified him some time later that he was soaring
         overhead Ventersburg, and was heading towards Kroonstad in a northerly direction.

         The pilot of ZS-GND later informed the second glider pilot that he was soaring overhead the Goldfields Gliding Club
         at Hennenman Aerodrome and that he was just flying around in the area. There was no further communication
         between the two glider pilots after this last conversation.

         According to the GPS trace, Cambridge logger that was fitted to the glider, at approximately 13:13:46Z, ZS-GND
         passed 2.5 km to the north of the Goldfields Gliding Club on a heading of 210° at an altitude of 2 621 ft, with the
         speed and the descent rate increasing. When the glider was at the top of the loop, the glider exited to the left in a
         barrel-type manoeuvre at an altitude of 2 538 ft (at 13:13:58Z).

         Although there was no eye-witness to the accident, a tractor driver indicted that he heard the sound of the glider
         breaking up in the air. Debris from the glider was found spread in a wide area, with the main wreckage in a ploughed
         maize field approximately 3 km south-west of Hennenman aerodrome. The glider was destroyed during the accident
         sequence.

         The glider pilot sustained fatal injuries in the accident.


         Probable Cause

         All evidence from the wreckage recovery suggests that high speed was experienced, causing flutter and a resultant
         structural break-up due to excessive g loading.




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                                AIRCRAFT ACCIDENT REPORT


Name of Owner                      :       135 Syndicate
Manufacturer                       :       Schleicher
Model                              :       AWS 20
Nationality                        :       South African
Registration Marks                 :       ZS-GND
Place                              :       3 km south of Hennenman Aerodrome
Date                               :       22 December 2007
Time                               :       1000Z


All times given in this report are co-ordinated universal time (UTC) and will be denoted by (Z). South
African Standard Time is UTC plus two hours.

Purpose of the Investigation:
In terms of Regulation 12.03.1 of the Civil Aviation Regulations (1997), this report was compiled in the
interests of the promotion of aviation safety and the reduction of the risk of aviation accidents or incidents
and not to establish legal liability.

Disclaimer:
This report is given without prejudice to the rights of the CAA, which are reserved.



1.      FACTUAL INFORMATION

1.1     History of Flight

1.1.1 On 22 December 2007, two gliders were winch-launched at approximately 1140Z
      from Goldfields Gliding Club at Hennenman in the Free State. After they were
      launched, they headed in a south-westerly direction along the railway line to
      Virginia. After soaring in the same two thermals, they separated overhead
      Virginia. The pilot of ZS-GND turned due east at Virginia and then headed in a
      north-easterly direction on a heading of 030° and passed over Ventersburg, east
      of Hennenman.

1.1.2 According to the pilot of the second glider, the pilot of ZS-GND notified him some
      time later that he was soaring overhead Ventersburg and was heading towards
      Kroonstad in a northerly direction.

1.1.3 Some time later, the pilot of ZS-GND again informed the second glider pilot that
      he was now soaring overhead the Goldfields Gliding Club at Hennenman
      Aerodrome and that he was just flying around in the area. There was no further
      communication between the two glider pilots after this last conversation.



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1.1.4 According to the GPS trace, Cambridge logger that was fitted to the glider, at
      approximately 13:13:46Z, the ZS-GND passed 2.5 km to the north of the
      Goldfields Gliding Club on a heading of 210° at an altitude of 2 621 ft, with the
      aircraft speed and the descent rate increasing. At the top of the loop at an
      altitude of 2 538 ft, the glider exited to the left in a barrel-type manoeuvre (at
      13:13:58Z).

1.1.5 Although there was no eye-witness to the accident, a tractor driver indicated that
      he heard the sound of the glider breaking up in the air. Debris from the glider was
      found scattered in a wide area, with the main wreckage in a ploughed maize field
      approximately 3 km south of Hennenman aerodrome. The glider was destroyed
      during the accident sequence.

1.1.6 The glider pilot sustained fatal injuries during the accident sequence.


1.2    Injuries to Persons

        Injuries       Pilot       Crew           Pass.          Other
        Fatal              1           -              -             -
        Serious             -          -              -             -
        Minor               -          -              -             -
        None                -          -              -             -


1.3    Damage to Aircraft

1.3.1 The glider was destroyed during the accident sequence.




                   Figure 1: The main wreckage in open farm field

1.4    Other Damage



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1.4.1 No other damage was caused to property on the ground.


1.5    Personnel Information

1.5.1 The glider pilot held a valid glider pilot’s licence, which was issued by the Soaring
      Society of South Africa.

        Nationality                        South African
        Licence No. ****************       Gender                Male        Age      34
        Licence Valid                      Yes           Type Endorsed       Yes
        Ratings                            Instructor’s Rating, Winch Rating
        Medical Expiry Date                31 January 2008
        Restrictions                       None
        Previous Accidents                 None

1.5.2 Pilot-in-command Flying Experience:

        Total Hours                           155.98
        Total Launches                        282.00
        Total Past 90 Days                      4.00
        Total on Type Past 90 Days              4.00
        Total on Type                          33.00

1.6    Aircraft Information

1.6.1 Airframe:

        Type                                            Schleicher ASW 20A
        Serial No.                                      20454
        Manufacturer                                    Alexander Schleicher, Germany
        Year of Manufacture                             1981
        Total Airframe Hours (At Time of Accident)      1 516.38
        Last Annual Inspection (Date & Hours)           17 Nov 2007 1 516.38 (726 launches
        Hours Since Last Annual Inspection              > 1 518
        Authority to Fly (Issue Date)                   10 December 2007
        Authority to Fly (Expiry Date)                  17 November 2008
        C of R (Issue Date) (Present Owner)             26 June 2003


1.6.2 Description of the ASW 20A Glider:

       The Schleicher ASW 20A glider is a 15 m wingspan glider of glass fibre
       composite construction. The glider utilizes air brakes for landing, which when
       combined with a positive deflection of the inner wing panel flaps, allow a steep
       descent for landing. The ailerons deflect negatively with landing flap applications.
       The cockpit provides a single seat and a single-piece front-hinged canopy can be
       jettisoned from within the cockpit. The glider can carry water ballast for increased




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        wing loading. The glider has a CG tow hook position. Limited aerobatics are
        permitted, such as loops, stall turns, lazy eights and chandelles.

1.6.3 Specifications of the ASW 20A Glider:

1.6.3.1         General characteristics
                •    Crew:                     One
                •    Wingspan:                 15 m (49 ft 3 in)
                •    Wing area:                10.5 m² (113 ft²)
                •    Aspect ratio:             21.43
                •    Empty weight:             254 kg (558 lb)
                •    Gross weight:             454 kg (1 000 lb)

1.6.3.2         Performance
                •     Min. speed at max all up mass:            75 km/h (46.5 mph)
                •     Min. sink:                                0.62 m/s at 78km/h
                •     Best glide angle:                         approx. 42:1
                •     VNE:                                      265 km/h (164.3 mph)

1.6.4     Flight characteristics:

        The ASW 20A is known as a very pleasant-handling glider in most respects.
        The landing flaps (65° in early models, 45° in later models), in conjunction
        with very effective airbrakes, allow the pilot to make exceptionally steep
        approaches and short-field landings when required.




                    Figure 2: A similar ASW 20A type glider during landing


1.7     Meteorological Information

1.7.1 The following information was obtained from the South African Aviation Weather
      Service:

1.7.1.1      Surface Analysis (1500Z, 22 December 2007)

             A trough of low pressure was present over the central part of the country, with
             high pressures over the eastern and western parts of the country.




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1.7.1.2      Upper air analysis

             At 500 hPa high-pressure system was present over the interior.

1.7.1.3      Satellite imagery

             The satellite imagery for 1500Z shows partly cloudy conditions in the
             Hennenman area.

1.7.1.4      Weather conditions in the vicinity of the Accident:

             No official weather observations were available at the time and place of the
             accident. The most likely weather conditions at the place of the accident at
             1500Z were as follows:
             • Temperature:          32°C
             • Dew Point:            09°C
             • Visibility:           > 10 km
             • Surface Wind:         020°TN at 4 kts
             • Cloud:                FEW cloud at 8 000 ft AGL

1.7.1.5   According to the Soaring Society of South Africa (SSSA), one glider pilot
          reported that it was an extremely hot day with cumulus cloud bases rising to
          14 000 ft and moderate to strong lift with moderate turbulence levels on the
          day that the accident occurred.

1.8    Aids to Navigation

1.8.1 The glider was equipped with the minimum VFR navigational equipment. In
      addition, the glider was also equipped with a GPS data logger that recorded
      aircraft position, groundspeed, altitude, etc.

1.9    Communications

1.9.1 According to available information, the pilot of another glider communicated on
      radio frequency 123.4 MHz with the pilot of ZS-GND during the flight, before the
      accident occurred. The pilot of ZS-GND commented that he was soaring
      overhead the Goldfields Gliding Club and was just flying around. There was no
      further communication from the ZS-GND pilot after this.

1.9.2 The communication system was serviceable prior to the accident.



1.10   Aerodrome Information

1.10.1 The accident occurred approximately 3 km south of the Hennenman Aerodrome
       in the Free State Province.


1.11   Flight Recorders




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      1.11.1 The accident glider was not fitted with a flight data recorder (FDR) or a cockpit
             voice recorder (CVR) nor was either required according to Civil Aviation
             Regulations (CARs). However, the glider was equipped with a GPS data logger,
             which showed the track, altitude, groundspeed, etc. of the glider. The data logger
             was recovered and downloaded at the Cambridge Factory in the USA and
             yielded track information for the glider.

      1.11.2 The track information was analysed using “See You” Software, which produces
             information in graphical form. The aircraft track can be viewed from any angle
             and the glider is depicted by a generic glider which can be scaled up or down for
             better visualisation purposes.

      1.11.3 The software programme measures the groundspeed, rate of turn, rate of
             climb/descent, etc. of the glider to calculate the theoretical bank angle and pitch
             angle, which are then used to depict the glider’s flying attitude.

      1.11.4 The tracks as obtained from the Cambridge logger of the glider are shown on the
             graph below:


         INITIAL SPEED    BARREL ROLL        RECOVERY           1ST SPIN
         BUILD-UP                                               ENTRY        RECOVERY         SPIN STABILIsED-
                                                                                              RECOVERY AND
                                                                                              SPAR FRACTURE


 5



 0


 -5

                                                                                 Series1
-10


-15



-20

                Figure 3: Graph showing the sink and climb rates for the
                           last two minutes and 24 seconds




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   100

     0

  -100

  -200

  -300
                 THIS PORTION IS NOT ON THE TRACE AS TRANSMISSION                             Series1
  -400           CEASED DUE TO BATTERY DISCONNECT WITH IN-FLIGHT
                 BREAK-UP PRIOR TO GROUND CONTACT
  -500

  -600

  -700

  -800



    Figure 4: Height gained and lost (in meters) for the last two minutes and
                             24 seconds of flight




                                                                       Kroonstad



                                                       Goldfields Gliding
                                                       Club -Hennenman




                                                          ZS-GND flew over Ventersburg, then
                                                          turned towards Hennenman when accident
                                                          occurred south of Hennenman
                           Virginia




Figure 5: Map of area showing where glider took off from Hennenman and routed
                    to Virginia then to Ventersburg and back



    1.12   Wreckage and Impact Information

    1.12.1 The main wreckage of ZS-GND was located at a GPS position of S28°03.246’



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       E027°02.214’, in a ploughed maize field approximately 3 km south of
       Hennenman Aerodrome.
.
1.12.2 The wreckage was spread over a distance of over 1.5 km, indicating both an in-
       flight break up at an altitude of approximately 1 500 m (4 800 ft) above ground
       level (AGL) and the presence of moderate wind speeds.




               Figure 6: The main wreckage in open field in farmland




Figure 7: A piece of upper right-hand wing fibreglass skin in an open field (pieces of
            wings and debris were spread over an approx. 1.5 km area)


1.12.3 Pieces of the airframe that were of light construction were found beyond the
       wreckage site and consisted mainly of skin sections of the right wing and a
       section of the tail plane damaged due to the in-flight break-up. The main wing
       panel sections were also found beyond the crash site, as were some aileron and
       flap pieces from the right wing.




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   Figure 8: The outer section of the right-hand wing in a field after break-up in air




             Figure 9: A section of the right-hand wing airbrake in a field
                                 after break-up in air


1.12.4 The right wing structure showed signs of flutter of the control surfaces of the wing
       and also signs that the wing failure took place under symmetrical loading
       conditions: the fracture positions were in the same position on both left and right
       wing panels. The right-hand wing panel pulled away from the wing skins and was
       found partially pinned to the left panel, which started losing its skins as well. Both
       wings broke free from the fuselage, and were located some distance from the
       fuselage section.




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             Figure 10: A large piece of left-hand wing that broke up in air


1.12.5 The fuselage impact at the accident site indicated that the fuselage was
       essentially intact except for a section of the tail plane that was damaged by the
       break-up of the right wing panel, indicated by airbrake scuff markings in the fin
       region. The right wing skins and small sections of canopy together with a section
       of flapperon from the right wing indicated torsional loading failures that were
       found in the wing panel flutter.




      Figure 11: The tailplane section and markings caused by airbrake impact

1.12.6 The cockpit interior, instruments and nose section of the glider were severely
       damaged by the fuselage impact.




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Figure 12: Google view of area where the glider wreckage and fragments (skin, etc.)
                          were spread over a wide area


1.13   Medical and Pathological Information

1.13.1 According to the Medico-Legal Post-Mortem Examination Report, the cause of
       death of the pilot was due to multiple severe injuries. No blood samples could
       be recovered.


1.14   Fire

1.14.1 Not applicable


1.15   Survival Aspects

1.15.1 Since the glider partly broke up during flight and would have thus been
       uncontrollable, the subsequent high impact would not have been survivable.




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1.16   Tests and Research

1.16.1 The Cambridge data logger was sent to and downloaded at the Cambridge
       Factory in the USA. The graphs from the Cambridge logger are displayed on
       page 8 of this report.


1.17   Organisational and Management Information

1.17.1 This was a private flight.

1.17.2 The glider was inspected by an approved person (AP) from the Soaring Society
       of South Africa (SSSA) according to the General Purpose Glider Airworthiness
       Inspection Report and Manual of Procedures on 17 November 2007.


1.18   Additional Information

1.18.1 The ASW 20 type gliders first flew in 1977 and were an instant success, winning
       numerous world and national championships. Gliders are very high-performance
       aircraft in terms of aerodynamic efficiency and rely on the pilot’s skill to make use
       of available warm air currents to enable them to gain altitude.

1.18.2 Gliders are usually aero-towed (towed behind a powered aircraft) or launched
       from a stationary winch on the ground. While in a thermal (rising air current), the
       glider pilot flies at a relatively slow speed that enables him to make tight turns
       and stay within the warm rising air. In this way, the glider gains altitude. Once
       sufficient altitude has been gained or the thermal becomes too weak, the pilot
       flies towards the next thermal or turns point and trades his altitude for airspeed.

1.18.3 Gliding is a very challenging sport and gliders often find themselves in one
       thermal together to best take advantage of the rising air currents. Every
       thermal finally dies out at a certain height and gliders at the top of the thermal
       exit the thermal while gliders at the bottom can still take advantage of the rising
       air. Once a pilot exits the thermal, he normally flies towards the next point until
       positive lift is again encountered.

1.18.4 The whole process of gliding in this way is therefore a trade-off between height
       and speed. The longer pilot thermals, the higher he will climb but the slower will
       be his average ground speed for that sector. However, if he leaves the thermal
       too early and exchanges height for speed, his ground speed will be high but he
       will be flying at a lower altitude and will have fewer options available to climb
       again.

1.18.5 The formation of clouds is a very good indicator of rising air or thermals and is
       often used by pilots as a visual indicator of rising air. In this way, a pilot can fly
       from cloud to cloud and cover vast distances (in excess of 1 000 km) on a good
       day.

1.18.6 According to the ASW 20 flight manual, the ASW 20 has been certificated
       according to the Airworthiness Requirements for Sailplanes and Powered
       Sailplanes, issued on 01 November 1975 by the German Authorities (LSFM).



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       Contrary to earlier requirements (BVS and LFS), some major modifications have
       to be observed. The minimum safety factor is 1.5. The safety factor is the
       proportion of ultimate load against limit load. This points to important
       consequences for the flight operations:

       •      Breaking loads will be reached either by exceeding the permissible loads
              by 50% or by exceeding the permissible speeds by √ 1.5 = 1.22. In other
              words, by only 22%. Therefore the stated placard speeds must be
              observed at all times.
       •      One major difference is that the new LFSM regulation requires a speed
              limit for strong air turbulence. This new requirement considers a 15 m/s (3
              000 ft/min) up or down gust.
       •      For easy understanding, the following examples are given as follows:

              a)     From a 5 m/s downdraft you enter a 10 m/s up-current. (This is a
                     + 15m/s gust) or from a 10m/s up-current, you enter a 5 m/s
                     downdraft (this is a –15 m/s gust).
              b)     From the downdraft of a rotor of –8 m/s you get into its up-current
                     of +7 m/s (this is a +15m/s gust). This turbulence can be absorbed
                     by the sailplane as long as the pilot does not change it by
                     additional loads due to unintended control deflections.

       •      The airworthiness requirement does not include gust and manoeuvre
              loads simultaneously. Gliding and meteorological literature show even
              stronger turbulence in cumulus clouds so that the maximum speed for
              strong turbulence can be too high in extreme situations. At manoeuvring
              speed, full control deflections can be applied, but only 80% of the
              deflections are allowed for elevator and rudder simultaneously.
       •      As mentioned above, the requirement does not cover gusts and
              manoeuvre loads at the same time. Therefore, aerobatic manoeuvres are
              not allowed in noticeable turbulence conditions.
       •      At red-line speeds, the sailplane can absorb either + or –7.5 m/s gusts
              (this is in transition from 3 m/s downdraft into 4.5 m/s lift) or one third of
              the possible deflections can be applied. Again, gust and manoeuvre loads
              cannot be absorbed simultaneously.

1.18.7 Airworthiness requirements are nothing more than a great amount of aviation
       experience gathered and are continuously developed by designers and
       aviation authorities in cooperation.

1.18.8 It is assumed that the sailplanes are operated with good judgement as in all
       areas of aviation.

1.18.9 Semi-aerobatics:

       Besides spinning (only with normal-to-rear CG limits is more than one turn
       possible), loops, stall turns, lazy eight and chandelles as well as combinations of
       these manoeuvres are allowed. Negative load factors are not certified. The flap
       control is actuated according to the remarks in the preface and the speed limits
       for the different flap settings must be carefully observed.




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1.18.9.1        Loops:

                A starting speed in the lowest point of about 160 to 180 km/h, 85 to 95 kts,
                or 100 to 112 mph is recommended with flap setting no. 1.


1.18.2          With flight tests with the damper installed, it was found after short
                familiarisation that the damper was no longer felt as discomfort. On the
                other hand, the directional stability of the ASW 20 in turbulent air is
                considerably increased as short and sharp gusts do not lead to
                uncontrolled aileron deflections due to the damper.

1.19     Useful or Effective Investigation Techniques

1.19.1 Not applicable

2.       ANALYSIS
2.1      The glider was winch-launched from Goldfields Gliding Club at Hennenman in
         the Free State Province. The pilot then headed in a south-westerly direction
         along the railway line to Virginia. After soaring in thermals overhead Virginia, the
         pilot headed in a north-easterly direction on a heading of 030°, and passed over
         Ventersburg.

2.2      According to the pilot of a glider who was also winch-launched at Goldfields
         Gliding Club, the pilot of ZS-GND notified him that he was heading towards
         Kroonstad in a northerly direction and again informed him later that he was
         soaring overhead the Goldfields Gliding Club at Hennenman Aerodrome. There
         was no further communication between the two glider pilots after this last
         conversation

2.3      The glider main wreckage was located approximately 3 km south of Hennenman
         Aerodrome after a tractor driver heard the glider breaking up during flight. The
         fuselage of the main wreckage indicated that the glider impacted the ground at
         an approximately 30 to 60° nose-down attitude. Debris from ZS-GND was found
         spread in a wide area. The pilot was located 17 m beyond the main wreckage
         and was fatally injured.

2.4      The glider debris showed signs of flapperon flutter in the control rod guides and
         damage due to flutter-induced overload. The flutter damper was still functional
         but had been torn free from the fuselage side mounting. Excessive wing bending
         loads and the wings fractured under symmetrical loading conditions.

2.5      All the evidence from the wreckage recovery suggested high in-flight speed, for
         example flutter and resultant structural break-up due to excessive g loading.

2.6      The asymmetry of the resultant break up may be the reason that the pilot did not
         manage to exit the glider as the resulting rotational motion may have prevented
         this.




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2.7    Unusual flight attitudes may have resulted in loss of ability to control the speed
       and loadings on the airframe such as during aerobatic flight. The glider has a
       very aerodynamically clean design and will accelerate quickly during any such
       aerobatic flight.

2.8    The glider may have been flown at high speed and encountered flutter due to
       rough air turbulence. The flutter may have caused a momentary loss of full
       control resulting in the overloading situation that resulted in the break-up of the
       airframe.

2.9    The most likely scenario is to surmise that the glider flutter and overload
       occurred at speed and that the break-up and flutter occurred at a similar stage as
       did the initial fracture of the sections of the canopy.

2.10   An initial interpretation of a logger trace was obtained from Cambridge Aero
       instruments, who manufactured the logging instrument recovered from the
       wreckage. The trace indicates that the glider entered a barrel roll or skew loop on
       recovery of which the glider attained a speed of over 310 km/hr. The reduction of
       speed as a result of the recovery indicated a very high g loading applied to the
       airframe. The glider recovered most probably in a broken and fluttered state after
       which the wings departed from the fuselage and the fuselage continued to
       impact.

3.     CONCLUSION

3.1    Findings

3.1.1 The pilot was the holder of a valid glider pilot’s licence, which had been issued by
      the Soaring Society of South Africa (SSSA).

3.1.2 According to available information, the aircraft had been properly maintained and
      held a valid Authority to Fly Certificate.

3.1.3 Evidence of signs of flapperon flutter in the control rod guides and damages due
      to flutter-induced overload was noted. The flutter damper was still functional but
      had been torn free from the fuselage side mounting. Excessive wing bending
      loads had been applied and the wings fractured under symmetrical loading
      conditions.

3.1.4 All the evidence from the wreckage recovery suggests high in-flight, flutter and a
      resultant structural break-up due to excessive g loading. The glider became
      uncontrollable after the glider started breaking up during flight.

3.1.5 The maximum rough airspeed for this glider is 180 km/hr. The manoeuvre speed
      is 175 km/hr and the maximum dive speed approximately 300 km/hr. Flight at
      speeds above the VNE (265 km/hr) and maximum dive speed can result in
      flutter; the airframe indications of flutter are likely indications of it having occurred
      during this aerobatic portion of the flight. The rapid reduction in airspeed
      indicates a high load having been applied to the airframe. The airframe seems to
      have been able to fly for about 90 seconds in a failed state before the wing
      assembly parted its position on the fuselage. All indications are that the wings




13/08/2010                    South African Civil Aviation Authority          Page 16 of 17
                                                                       Ref. No: CA18/2/3/8407


         lifted out of the top part of the fuselage above the normal wing position and the
         fuselage then dived into the ground.

3.1.6 There is no evidence that any pre-existing medical factors could have contributed
      to the cause of the accident.



3.2      Probable Cause/s

3.2.1 All the evidence from the wreckage recovery suggests high in-flight, for example
      flutter and a resultant structural break-up due to excessive g loading.

4.       SAFETY RECOMMENDATIONS
4.1      None


5.       APPENDICES

5.1      None




      Report reviewed and amended by the Advisory Safety Panel on 20 April 2010.

                                                 -END-




13/08/2010                    South African Civil Aviation Authority        Page 17 of 17

				
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