AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY

Transcription

1 Section/division Accident & Incident Investigation Form Number: CA 12-12a AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference: Aircraft Registration ZU-BCU Date of Accident 23 December 2006 Time of Accident 0920Z Type of Aircraft Bushbaby 450 (Aeroplane) Type of Operation Private Pilot-in-command Licence Type Microlight Age 50 Licence Valid Yes Pilot-in-command Flying Experience Total Flying Hours Hours on Type Last point of departure Next point of intended landing Koeberg Flight Park (aka Morningstar Aerodrome) Fisantekraal Aerodrome (FAFK) Location of the accident site with reference to easily defined geographical points (GPS readings if possible) 200m from threshold of runway 02 at Koeberg Flight Park (GPS: S E , elevation 2 00ft) Meteorological Information Surface wind: 190 TN / 12 kts; Temperature: 25 C; Visibility: CAVOK Number of people on board No. of people injured 0 No. of people killed 1 Synopsis The pilot, the sole occupant on board, took off from Fisantekraal Aerodrome earlier in the morning on a local pleasure flight and landed at Koeberg Flight Park, also known as Morningstar Aerodrome. After chatting for a short time to fellow pilots, he prepared to return to Fisantekraal. He chose runway 20 for the takeoff as the wind was from the south-south-west at 12 knots. According to an eye-witness, the pilot executed a left turn after takeoff feet above ground level and during this manoeuvre, the left wing dropped abruptly. The aircraft fell to the ground in a nosedown attitude, fatally injuring the pilot. Probable Cause The pilot stalled the aircraft while executing a low-level turn shortly after takeoff. IARC Date Release Date CA 12-12a 23 FEBRUARY 2006 Page 1 of 12

2 Section/division Accident & Incident Investigation Form Number: CA 12-12a AIRCRAFT ACCIDENT REPORT Name of Owner/Operator : Mr L. van Wyk Manufacturer : Kitplanes for Africa Model : Bushbaby 450 Nationality : South African Registration Marks : ZU-BCU Place Date : 23 December 2006 Time : 0920Z : Koeberg Flight Park 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 2 hours. Purpose of the Investigation In terms of Regulation of the Civil Aviation Regulations (1997), this report was compiled in the interest 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 produced without prejudice to the rights of the CAA, which are reserved. 1. FACTUAL INFORMATION 1.1 History of Flight The pilot, the sole occupant on board, departed Fisantekraal Aerodrome on the morning of 23 December 2006 on a local pleasure flight, landing at Koeberg Flight Park, also known as Morningstar Aerodrome After chatting to fellow pilots for a while, he prepared to return to Fisantekraal. He chose runway 20 for the takeoff as the wind was from the south-south-west at 12 knots. According to an eye-witness, who was also a pilot, the pilot of BCU took off and, judging by the engine note, seemed to throttle back during the climb-out. At a height of feet above ground level, he initiated a left turn. Shortly thereafter, the eyewitness saw the left wing drop abruptly and the aircraft dive. The aeroplane struck the ground in a nose-down attitude, fatally injuring the pilot The accident occurred during daylight at the geographical position South East at an elevation of 200 fe et above mean sea level (AMSL). CA 12-12a 23 FEBRUARY 2006 Page 2 of 12

3 1.2 Injuries to Persons Injuries Pilot Crew Pass. Other Fatal Serious Minor None Damage to Aircraft The aircraft was destroyed by the ground impact. Figure 1. The wreckage seen from the aft left-hand side. 1.4 Other Damage None. 1.5 Personnel Information Pilot-in-command Nationality South African Gender Male Age 50 Licence Number ***************** Licence Type Microlight Licence valid Yes Type Endorsed Yes Ratings Microlight Instructors Rating Grade B Medical Expiry Date 30 April 2007 Restrictions To fly with suitable corrective lenses Previous Accident None CA 12-12a 23 FEBRUARY 2006 Page 3 of 12

4 Flying Experience Total Hours Total Past 90 Days 17.8 Total on Type Past 90 Days 5.1 Total on Type Aircraft Information Airframe Type Bushbaby 450 Serial Number 37 Manufacturer Kitplanes for Africa Year of Manufacture 1996 Total Airframe Hours (At time of Accident) 652.8* Last MPI (Hours & Date) November 2006 Hours since Last MPI 2.8 Authority to Fly (Issue Date) 5 December 2006 Authority to Fly (Expiry Date) 29 November 2007 C of R (Issue Date) (Present Owner) 27 January 1997 Operating Categories Microlight amateur-built NOTE*: The airframe hours of the aircraft at the time of the accident were obtained from the flight folio. It was not possible to obtain any reading from the Hobbs meter as this was destroyed during the impact Engine Type Rotax 912 Serial Number Hours since New Hours since Overhaul TBO not yet reached Propeller Type Warp 3 blade Serial Number Not available Hours since New Hours since Overhaul TBO not yet reached Weight & Balance Weight and balance were not regarded as a factor in this accident as the pilot was the sole occupant on board and there was no additional ballast. His weight, according to the post-mortem report, was 82 kg. A substantial amount of fuel had already been burned off at the time of the flight. CA 12-12a 23 FEBRUARY 2006 Page 4 of 12

5 1.7 Meteorological Information An official weather report was obtained from the South African Weather Services for 23 December 2006 at 0920Z at Koeberg Flight Park. i. Surface Analysis A weak cold front was situated west of Cape Town with a trough of low pressure over the Western Cape. There was a coastal low on the KwaZulu- Natal coast. ii. Satellite Imagery This showed no cloud over the South Western Cape Weather conditions in the vicinity of the accident: i. No official observations were available at the time and place of the accident. Cape Town weather office at Cape Town International Airport reported the following weather at 0920Z: Temperature C Wind direction TN Wind speed - 12 kts ii. A study of the synoptic situation showed that the winds north of Cape Town were more south-westerly. The most likely conditions at the place of the accident were: Temperature C Wind direction TN Wind speed - 12 kts 1.8 Aids to Navigation The aircraft was equipped with standard navigational equipment as per the equipment list approved by the regulator. The accident occurred shortly after takeoff, when navigational equipment would have had very little or no relevance to the accident. 1.9 Communications The pilot broadcast his intentions on the local VHF aerodrome frequency, MHz, prior to takeoff. This was an unmanned aerodrome outside of controlled airspace. CA 12-12a 23 FEBRUARY 2006 Page 5 of 12

6 1.10 Aerodrome Information Aerodrome Location 25 km north of Cape Town, next to the N7 highway Aerodrome Co-ordinates South East Aerodrome Elevation 200 feet AMSL Runway Designations 02/20 Runway Dimensions 650 m x 10 m Runway Used 20 Runway Surface Asphalt Approach Facilities None Aerodrome Status Unlicensed 1.11 Flight Recorders The aircraft was not equipped with a flight data recorder (FDR) or a cockpit voice recorder CVR. Neither was required by regulation to be fitted to this type of aircraft Wreckage and Impact Information The aircraft struck the ground in a westerly direction approximately 200 m beyond the threshold of runway 02 at Koeberg Flight Park on firm, level ground. There was no evidence of forward movement following ground impact. Aircraft deformation suggests that the aeroplane hit the ground in a steep nose-down attitude. The propeller separated from the hub assembly and was imbedded in the soft sand. Two of the three composite propeller blades fractured at the hub assembly. The engine was pushed back into the cockpit, resulting in substantial deformation of the cabin area. The leading edge of the right wing displayed signs of ground impact. The left wing remained fairly intact with some buckling evident of the wing and wing strut. The flaperon partially separated from the wing and remained attached only to the inner attachment bracket The empennage did not make contact with the ground and was undamaged. The main undercarriage was destroyed during the impact sequence, while the tail wheel remained undamaged Examination of the rudder, elevator, flaperons and throttle control runs did not reveal any evidence of control malfunction. All damage observed was consistent with the effects of ground impact. CA 12-12a 23 FEBRUARY 2006 Page 6 of 12

7 Figure 2. The wreckage of ZU-BCU. Figure 3. The engine forced back into the cockpit Medical and Pathological Information A post-mortem examination was performed on the pilot. This concluded that the cause of death was multiple deceleration injuries and their consequences The toxicological tests results were not available at the time this report was compiled. Should these have a bearing on the circumstances relating to this accident, the report will be revised accordingly. CA 12-12a 23 FEBRUARY 2006 Page 7 of 12

8 1.14 Fire There was no evidence of a pre- or post-impact fire Survival Aspects Due to the high kinetic forces associated with the impact, this was not considered a survivable accident The pilot was properly restrained at the time of the accident. His safety harness had to be cut by emergency personnel in order to free his body from the wreckage Tests and Research Engine teardown inspection: The engine, a Rotax 912 Serial No was removed from the wreckage and a teardown inspection performed with the assistance of an Approved Person. Impact was in a steep nose-down attitude, resulting in substantial deformation of the engine cradle and associated components, mostly to the front and sides of the engine. The engine oil cooler, which was installed below the engine just aft of the propeller flange, was destroyed during the impact. However, all oil pipes were still secure. The following observations were noted during the inspection: All the gears in the gearbox / sprag clutch assembly were intact and undamaged. The generator assembly, located at the rear of the engine, was undamaged. The housing, however, contained a substantial amount of dirt and sand. The carburettors were intact and the carburettor bowls of both units displayed evidence of fuel. All the mechanical linkages associated with the operation of the carburettors were intact. The air filter units attached to the carburettors were substantially deformed during the impact sequence. The cylinders sustained limited impact damage. The pistons and oil/compression rings were undamaged and in a generally good condition. All valves (inlet and outlet) were undamaged and accounted for. The crankcase and crankshaft assembly were in good condition. The camshaft was in good condition. The spark plugs displayed a greyish colour, indicative of normal engine operation (correct fuel/air mixture). A substantial amount of oil was still evident within the crankcase assembly during the teardown procedure. No mechanical defect was found during the teardown procedure that could have contributed to the engine failing in operation. CA 12-12a 23 FEBRUARY 2006 Page 8 of 12

9 1.17 Organisational and Management Information This was a private flight. The pilot hired the aircraft for his personal use from an aviation training organisation at Fisantekraal aerodrome The aircraft, which was registered under the Non-type Certificate Aircraft category, was maintained by an Approved Person (AP). The AP was accordingly accredited by the Aero Club of South Africa under the Approved Person Scheme Additional Information Departure stall: During takeoff and the initial stage of departure, an aircraft enters into and passes through a critical condition of flight. After leaving the ground and accelerating to climbing airspeed, the aircraft passes through a period of low airspeed and low altitude. Any abrupt pull-up or reduction in engine power could cause the aircraft to stall. Should a mishap occur at this point and good airmanship prevail, the throttle can be closed and a safe landing made straight ahead, with only small changes in direction to avoid obstructions. However, should an aircraft s attitude become too nose-high after rotation, a stall may occur from which a successful recovery may not be possible. Additionally, if the aircraft is in near-stalled condition, it will not be able to climb sufficiently to clear obstacles in the flight path. Therefore, establishing the correct nose-up attitude for a climb after takeoff is imperative. As part of the departure procedure, the pilot should take great care to establish the correct noseup attitude when executing a climbing turn, especially if the turn is carried out before a safe height is reached. Another critical departure procedure is the overshoot resulting from a missed approach. More often than not, when a decision is reached to discontinue an approach, the airspeed is low and the flaps are extended. In addition, it may be necessary, for traffic pattern purposes, to turn very shortly after initiating the missed approach. To avoid conditions that may lead to a stall or near-stall, pilots should pay particular attention to the following: 1. Apply full power. This is a form of takeoff under adverse conditions so nothing less than full power is adequate. 2. Application of power plus the nose-up trim used during the approach will tend to force the aircraft into a nose-high attitude. This should be anticipated and compensated for by holding the correct pitch attitude until the trim can be readjusted. 3. Very few aircraft are able to sustain a climb with flaps fully extended. The flaps should be retracted smoothly in accordance with the instructions in the aircraft flight manual. Should the manual not indicate how to raise the flaps, it is recommended that they be raised in stages. When the flaps are fully retracted immediately, a sudden loss of height can occur. Attempts to arrest this descent by raising the nose suddenly may induce a stall. CA 12-12a 23 FEBRUARY 2006 Page 9 of 12

10 Stalls during turns: When an aircraft is stalled during a level or descending turn, the inside wing normally stalls first, and the aircraft will roll to the inside of the turn. In a level turn, the inside wing is travelling more slowly than the outside wing and obtains less lift, causing it to sink and increase its angle of attack. Under the proper conditions, this will produce a stall. During a descending turn, the path described by the aircraft is a downward spiral; therefore, the inside wing is meeting the relative airflow at a steeper angle of attack and is the one to stall first and drop lower. However, during a climbing turn, the path described by the aircraft is an upward spiral; therefore, the outside wing is meeting the relative airflow at a steeper angle of attack than the lower wing. As a result, the higher wing will normally stall first and drop abruptly when the stalled condition occurs. Quoted from Transport Canada Flight Training Manual 4 th Edition, pp 79 and 80) 1.19 Useful or Effective Investigation Techniques None. 2. ANALYSIS 2.1 The aircraft was in possession of a valid Authority to Fly and was properly maintained. No evidence was found of any defect with the aircraft that could have caused or contributed to the accident. The pilot was properly licensed and held a valid aviation medical certificate. This was the pilot s second flight of the day. Fine weather conditions prevailed in the area at the time of the flight, with the wind reported to be from the south-south-west at 12 knots, according to the official weather report. The pilot used runway 20, which allowed for a takeoff into the wind. 2.2 It is uncertain why the pilot did not maintain runway heading before proceeding with the left turn at a safe height. It is believed that he most probably wanted to demonstrate his flying ability to his watching fellow aviators. He therefore performed an unplanned manoeuvre based on an impulsive decision that was inadequately thought through. He failed to assess the prevailing wind adequately and proceeded with a downwind turn at a critical phase of the flight (low groundspeed and high engine power demand). 2.3 Once the left wing dropped as the turn was commenced, the pilot had very limited time to react and recover from the stall due to the insufficient height available. The aircraft struck the ground in a steep nose-down attitude. 3. CONCLUSION a) Findings (i) The pilot was the holder of a valid microlight aeroplane pilot s licence and had the aircraft type endorsed in his logbook. CA 12-12a 23 FEBRUARY 2006 Page 10 of 12

11 (ii) The pilot held a valid aviation medical certificate issued by a CAA-approved medical officer. (iii) The aircraft was in possession of a valid Authority to Fly at the time of the accident. (iv) The last annual inspection carried out on the aircraft prior to the accident flight was certified on 29 November (v) No evidence was found of any defect or malfunction in the aircraft that could have caused, or contributed to, the accident. (vi) The mass and centre of gravity of the aircraft were not considered to be factors in this accident. (vii) The prevailing wind at the aerodrome was reported to be from the southsouth-west at 12 knots. (viii) The pilot used runway 20 for takeoff. (ix) When the left wing dropped, insufficient height was available to recover from the stall condition. (x) The aircraft impacted with level open ground approximately 200 m past the threshold of runway 02, fatally injuring the pilot. (xi) This was not regarded as a survivable accident. b) Probable Cause/s (i) The pilot stalled the aircraft while executing a low-level turn shortly after takeoff. c) Contributory Factor/s (i) (ii) The pilot deviated from standard operating procedures by executing a turn before a safe height was reached. This was possibly an unplanned spur of the moment manoeuvre by the pilot. The pilot turned downwind at low level and low speed, which aggravated the aerodynamic flying characteristics of the aircraft. (iii) When the left wing dropped, there was insufficient height available for the pilot to recover from the stall. 4. SAFETY RECOMMENDATIONS 4.1 None. CA 12-12a 23 FEBRUARY 2006 Page 11 of 12

12 5. APPENDICES 5.1 None. Report reviewed and amended by the Advisory Safety Panel on 19 January END- CA 12-12a 23 FEBRUARY 2006 Page 12 of 12