Pilot s diverted attention contributing to loss of helicopter attitude at low height, resulting in a tail strike.

Transcription

1 Section/division Occurrence Investigation Form Number: CA 12-12a AIRCRAFT INCIDENT REPORT AND EXECUTIVE SUMMARY Aircraft Registration ZS-MEX Date of Incident Type of Aircraft Robinson R44 Raven II (Helicopter) Pilot-in-command Licence Type Commercial (CPL) Pilot-in-command Flying Total Flying Experience Hours Last point of departure Next point of intended landing Reference: CA18/3/2/ December 2014 Time of Incident 1210Z Type of Operation Lebala Game Lodge, Limpopo province Commercial Age 25 Licence Valid Yes Hours on Type 82.1 Grand Central aerodrome (FAGC), Gauteng province Location of the incident site with reference to easily defined geographical points (GPS readings if possible) Lebala Game Lodge at GPS co-ordinates determined to be S E at the elevation of above mean sea level (AMSL) Meteorological Information Number of people on board Synopsis Temperature, 22 C: Visibility, 10 km: Wind directio n, 360, Dew point, 12 C: Cloud base, feet above ground level. No. of people No. of people killed 0 injured On Thursday morning of 25 December 2014, a Robinson R44 Raven II helicopter departed from O R Tambo international (FAOR) airport on a charter flight with the pilot and a passenger on-board bound for Lebala Game Lodge in Limpopo. The flight was uneventful and both occupants disembarked and proceeded towards the reception. The passenger checked in while the pilot enjoyed a cup of coffee with other guests. The pilot later went back to the helipad and prepared the helicopter for a repositioning flight. All was normal, and the pilot boarded the helicopter and started the engine. The engine and fuel flow indications were normal and he advanced the collective lever and lifted off the helicopter to a height of about two metres AGL before hovering for departure. During the process the right hand side door of the helicopter opened, and in an attempt to close it, the pilot allowed the helicopter s nose to pitch up resulting in a tail strike. Damage was limited to the lower vertical stabiliser and the tail rotor guard and the pilot was unharmed. The investigation revealed that the incident was as a result of the pilot s diverted attention while attempting to close the door at low height, causing inadvertent backward tilting of the cyclic control and resulting in a tail strike. Probable Cause Pilot s diverted attention contributing to loss of helicopter attitude at low height, resulting in a tail strike. IARC Date Release Date CA 12-12b 25 MAY 2010 Page 1 of 15

2 Section/division Occurrence Investigation Form Number: CA 12-12a Telephone number: address of originator: AIRCRAFT INCIDENT REPORT Name of Owner/Operator : Blue Turtle Technologies (PTY) LTD Manufacturer : Robinson Helicopter Company Model : Robinson R44 Raven II Nationality : South African Registration Marks : ZS-MEX Place : Lebala Game Lodge Date : 25 December 2014 Time : 1210Z 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 given without prejudice to the rights of the CAA, which are reserved. 1. FACTUAL INFORMATION: 1.1 History of Flight: On Thursday morning 25 December 2014, the pilot drove from his home to the operator s facility, Blue Turtle Technologies based at Grand Central (FAGC) aerodrome to prepare the helicopter for a charter flight to Lebala Game Lodge located in the Valwater District Municipality, Limpopo. The pilot scrutinised the helicopter s technical documentation and all was properly signed with no outstanding technical snags. The maintenance crew pulled the helicopter out of hangar to the helipad. The helicopter was then fuelled to capacity with 100 LL Avgas followed by a thorough preflight inspection by the pilot The pilot stated that everything was normal and he boarded the aircraft and secured himself with the safety harness. He then communicated with the FAGC tower controller and requested to start and take off to O R Tambo international (FAOR), which was 10 nautical miles (NM) from FAGC. The request was acknowledged and the tower controller stated that he had a clear view of the apron area and was watching the helicopter. The helicopter took off and routed south easterly at 90 knots (kt) indicated airspeed (AIS), where upon a successful landing at FAOR was carried out after 10 minutes. CA 12-12b 25 MAY 2010 Page 2 of 15

3 Figure 1: Google Earth map depicting FAGC and FAOR Within few minutes the passenger availed himself. His 20 kg baggage was loaded onto the helicopter and he then embarked. The pilot secured the passenger and provided him with a safety briefing before start-up. The before start checklist was completed and the engine was started. The engine and fuel flow gauge indications were normal and the pilot took off after being cleared by FAOR air traffic controller (ATC). The helicopter took off and headed in a Northerly direction, landing smoothly on the game lodge helipad. Approximately 1.2 hours later, upon landing, the pilot shut down the engine and off-loaded the baggage before proceeding to the lodge reception. At the reception, the passenger checked in and the pilot was offered a cup of coffee The pilot later went back to the helipad and prepared the helicopter for a repositioning flight to FAGC. All was normal and he boarded the helicopter and started the engine. The engine and fuel flow indications were normal and he advanced the collective lever, lifting off the helicopter to a height of about 2 m AGL before hovering for departure. He then tilted the cyclic forward and the helicopter started to gain forward momentum. During this time, the right hand side door (pilot door) opened. The pilot reported that he struggled to close the door with his right hand. The helicopter pitched up, yawed to the left and then drifted to the right. According to the pilot, weather was fine but everything happened so quickly and he didn t notice any damage happening. He then gave more power and climbed to approximately 50 ft where he was able to close the door. CA 12-12b 25 MAY 2010 Page 3 of 15

4 1.1.5 The helicopter then proceeded to FAGC at ft, 90 kt indicated airspeed. The landing at FAGC was uneventful. Before shutdown, the main tank fuel gauge indicated quarter full, and the auxiliary was between quarter full and empty. After flight inspection revealed a damaged lower vertical stabiliser and the tail rotor guard. No injury was reported. The operator s aircraft responsible person was notified and the matter was reported to the aircraft accident and incident investigation (AIID). The flight was conducted under the provisions of Part 127 of the Civil Aviation Regulations of 1997, as amended and the operator was in possession of a valid air operating certificate (AOC) No CA/N14OD, which permitted the helicopter s use for charter flights The incident happened in day light at GPS co-ordinates determined to be S E at an elevation of feet AMSL. Figure 1 show Lebala Game Lodge where the incident occurred. Figure 2: Lebala Game Lodge and the helipad on a Google Earth map 1.2 Injuries to Persons: Injuries Pilot Crew Pass. Other Fatal CA 12-12b 25 MAY 2010 Page 4 of 15

5 Serious Minor None Damage to Aircraft: Damage was limited to the lower vertical stabiliser and the tail rotor guard. A damaged lower vertical stabiliser and the tail rotor guard Figure 3: The helicopter in the hangar CA 12-12b 25 MAY 2010 Page 5 of 15

6 Figure 4: Closer view of the lower vertical stabiliser 1.2 Other Damage: None. 1.5 Personnel Information: Nationality South African Gender Male Age 25 Licence Number Licence Type Commercial (CPL) Licence valid Yes Type Endorsed Yes Ratings Night and Instrument ratings Medical Expiry Date 13 May 2015 Restrictions None Previous Incidents Nil CA 12-12b 25 MAY 2010 Page 6 of 15

7 Flying experience: Total Hours Total Past 90 Days 56.5 Total on Type Past 90 Days 52.2 Total on Type 82.1 *NOTE: The investigation into South African civil aviation authority (SA CAA) maintenance pilot s file revealed no enforcement actions, rating failure, or retest history. The pilot licence was valid and he was rated on Robinson helicopter series. 1.6 Aircraft Information: Description: The Robinson R44 is a single-engine four-seater light utility helicopter constructed primarily of metal and equipped with skid-type landing gear. The helicopter is powered by an IO540 six-cylinder horizontally opposed fuel-injected engine with angled valve head and tuned induction capable of producing 300 horsepower. The engine is controlled by an electronic governor, also manufactured by Robinson Aircraft Company. Fuel is fed by gravity, with an electric prime pump. Should the engine inadvertently shut down, the loss of oil pressure turns the pump off, preventing the engine from flooding during a restart. The output shaft powers both the cooling fan and the drive belt sheave. The cooling fan provides air to cylinder heads and oil coolers, and also serves for gearbox cooling and cabin heating. The main rotor system is a twoblade underslung teetering hinge. The all-metal stainless steel blades are connected to the hub by two sealed Tefloncoated coning hinges. The pitch change bearings are wet and enclosed by a neoprene boot at the blade root. The main gearbox contains a single-stage splash-lubricated gear set and is driven by a V-belt sheave that lies directly above the engine sheave. The sprag one-way drive clutch is contained within the upper sheave and can easily be checked for operation by the pilot during pre-flight inspection. An automatic clutch actuator raises the upper sheave when the pilot engages the clutch, and a tensioner automatically stops the engagement when the correct tension is achieved. It also automatically adjusts tension in flight. The tail rotor drive does not have any hanger bearings; it drives a splash-lubricated gearbox. CA 12-12b 25 MAY 2010 Page 7 of 15

8 The two metal tail rotor blades are attached to a teetering hub with a fixed coning angle, and use elastomeric teetering bearings and Teflon pitch-change bearings. The hydraulic system consist of a pump, three servos, a reservoir and lines boosting the main rotor flight control while eliminating cyclic and collective feedback forces. At the same time the flight controls maintain a direct mechanical link, allowing full control should the hydraulics fail. The pump is driven by the main gearbox, operating at a relatively low pressure of 450 to 500 pressure per square inch (psi). The pilot can turn the hydraulics off, although electrical power is required to do so, providing a fail-safe system. The 28-volt DC electrical system powers a single bus bar and includes an alternator, voltage controller, and 24-volt battery. Standard lighting on the R44 helicopter includes strobe, navigation, panel and map lights. The warning lights are extensive, and the low rotor warning also includes a horn activated at 97 per cent rpm. Another standard feature is the four-place voice activated intercom system. The helicopter has a press-to-talk (PTT) switch in the pistol grip on the cyclic control, which is activated by the index or key finger. See Figure 5. ON/OFF hydraulic toggle switch Press to talk (PTT) switch on a T-bar cyclic Figure 5: Robinson R44 Raven II cyclic The hydraulic switch is located on the front of the cyclic stick. All the equipment has been installed for easy accessibility for the observer or pilot in day or night operations, including independent audio controls, map lights and a pouch for binoculars. Removable left seat pedals and collective control may be installed to allow a rated copilot to control the helicopter using the centre cyclic control. Figure 6 shows the exterior of the incident helicopter. CA 12-12b 25 MAY 2010 Page 8 of 15

9 Figure 6: Robinson R44 Raven II helicopter Airframe: Type Robinson R44 Raven II Serial Number Manufacturer Robinson Helicopter Company Service ceiling ft Maximum take-off weight lb Empty weight lb Date of Manufacture 2007 Total Airframe Hours (At time of incident) Last MPI (Hours & Date) October 2014 Total Hours Flown Certificate of Airworthiness (Issue Date) 25 September 2007 Certificate of Airworthiness (Expiry Date) 24 September 2015 Airworthiness Directives and Service Bulletins Complied with C of R (Issue Date) (Present owner) 13 May 2009 Fuel used Avgas LL 100 Operating Categories Standard Part 127 CA 12-12b 25 MAY 2010 Page 9 of 15

10 Engine: Type Serial Number Lycoming IO-540-AE1A5 L E Hours since New Hours since Overhaul Meteorological Information: Weather information as obtained from the pilot s questionnaire: Wind direction 360 Wind speed 12 knots Visibility 10 km Temperature 22 C Cloud cover Few Cloud base ft Dew point 12 C 1.8 Aids to Navigation: The helicopter was fitted with standard navigation equipment as approved at the time of certification. 1.9 Communications: No difficulties with communications were known or reported prior to the incident. In addition, no malfunction on any of the equipment was reported at the time of the incident Aerodrome Information: The incident occurred outside airport boundaries Flight Recorders: The helicopter was not fitted with a flight data recorder (FDR) or a cockpit voice recorder (CVR), neither was it required in terms of the South African Civil Regulations to be fitted to this helicopter type. CA 12-12b 25 MAY 2010 Page 10 of 15

11 1.12 Wreckage and Impact Information: Examination of the helicopter, revealed evidence consistent with the helicopter tail having contacted the ground surface with light force. There was no other damage found on the tail boom. The flight control system was examined and no anomalies were found Medical and Pathological Information: Not applicable Fire: No pre or post impact fire was reported Survival Aspects: The incident was considered survivable Tests and Research: The operation of the cyclic and collective controls confirmed that the control systems from the pilot inputs to the hydraulic servos were correctly connected and capable of functioning appropriately. All the helicopter doors were examined and found to be latching without difficulties. The investigation had concluded that the pilot had inadvertently applied back pressure on the cyclic control, as he was attempting to close the door, allowing the abrupt nose-up pitch attitude resulting in a tail strike. This incident highlights the importance of ensuring all doors are secured prior to take-off. Having said that, the opening of a door in flight will not normally affect the operation of the R44 helicopter, yet the inherent reaction to immediately deal with such an event can be quite strong. This reaction may be hard to overcome and in the event of an unexpected situation like on this occurrence, it is vital that pilots should continue to fly the helicopter Organisational and Management Information: This was a commercial flight The aircraft maintenance organisation (AMO) that performed the last inspection on the helicopter was in possession of a valid AMO approval certificate No 27. CA 12-12b 25 MAY 2010 Page 11 of 15

12 1.18 Additional Information: None Useful or Effective Investigation Techniques: None. 2. ANALYSIS: 2.1 The available information revealed that fine weather conditions prevailed in the area at the time of the occurrence. Therefore the weather was considered not to have any bearing on the incident. The pilot was the holder of a valid commercial helicopter pilot s license and was proficient to perform the task at hand. Available information indicated that the pilot had flown a total of hours preceding the accident, of which all of those hours were on the Robinson helicopter series. 2.2 The mishap occurred after the right hand side door (pilot door) went open on departure from Lebala Game Lodge on a repositioning flight to FAGC. The investigation concluded that the mishap was as a result of the pilot diverted attention from the operation of the helicopter at low height and his inadvertent backward tilting of the cyclic control while attempting to close the door resulting in a tail strike. In addition, his inadequate before start check, specifically his failure to properly latch/close the door, suggests that he was somewhat in hurry to return to FAGC. The incident could have been avoided should the pilot had considered to land the helicopter after the door went open and properly closing it before returning to FAGC. 3. CONCLUSION: 3.1 Findings: The pilot was a holder of a valid commercial pilot s licence and had the helicopter type endorsed in his logbook The pilot s medical certificate was valid without restrictions Fine weather conditions prevailed at the time and were not considered to have had bearing on the occurrence The AMO that performed the last inspection on the helicopter prior to the occurrence was in possession of a valid AMO approval certificate No The operation of the cyclic and collective controls confirmed that the control systems from the pilot inputs to the hydraulic servos were correctly connected and capable of functioning appropriately. CA 12-12b 25 MAY 2010 Page 12 of 15

13 3.1.6 All the helicopter doors were examined and found to be latching without difficulties The helicopter was in possession of a valid certificate of airworthiness at the time of the incident The incident was regarded as survivable. 3.1 Probable Cause/s: Pilot s diverted attention contributing to loss of the helicopter attitude at low height, resulting in a tail strike. 3.2 Contributing factor/s: Poor airmanship. 4. SAFETY RECOMMENDATIONS: 4.1 None. 5. Appendices: 5.1 Robinson R44 operating limitations and the pilot s checklist. CA 12-12b 25 MAY 2010 Page 13 of 15

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