AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY

Transcription

1 Section/division Occurrence Investigation Form Number: CA 12-12a AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference: CA18/2/3/8635 Aircraft Registration ZS-HFW Date of Accident 14 April 2009 Time of Accident 11:30Z Type of Aircraft Robinson R44 II Type of Operation Training ( Conversion) Pilot-in-command Licence Type Commercial Age 43 Licence Valid Yes Pilot-in-command Flying Experience Total Flying Hours Hours on Type 61.9 Last point of departure Next point of intended landing George Aerodrome (FAGG) Mossel Bay Aerodrome (FAMO) Location of the accident site with reference to easily defined geographical points (GPS readings if possible) Threshold 09 at Mossel Bay Aerodrome. Meteorological Information Surface wind 012 /5kts. Visibility: CAVOK Number of people on board No. of people injured 0 No. of people killed 0 Synopsis On 14 April 2009 the instructor pilot (IP) and student pilot (SP) took off from George Aerodrome (FAGG) to Mossel Bay Aerodrome (FAMO) on a training flight (conversion training flight).the SP was undergoing conversion training onto a Robinson R44 helicopter when the accident occurred. The training required that the hydraulic switch be deactivated or switched off. Following the deactivation of the hydraulic system, the SP informed the IP of the stiffness of the controls. The IP explained the need to have the hydraulic system off. The SP then managed to get the helicopter on to a hover and held a steady hover for a short period before loosing control. The instructor pilot instructed the student pilot to activate hydraulic switch which is situated only on the student s side of cyclic control. The student did not activate the hydraulic switch timeously, resulting in the helicopter impacting the ground hard. The instructor and the student sustained no injuries, but the aircraft was destroyed. Probable Cause Helicopter vertically impacted the ground hard following the pilot's loss of control during hover. Contributory Failure of the instructor to react by taking over control of the helicopter as it can be flown with the hydraulic switch in the off position. IARC Date Release Date CA 12-12a 23 FEBRUARY 2006 Page 1 of 14

2 Section/division Occurrence Investigation Form Number: CA 12-12a Telephone number: address of originator: AIRCRAFT ACCIDENT REPORT Name of Owner Manufacturer Model : R44 II Nationality : South Africa Registration Marks : ZS-HFW Place : Mossel Bay Date : 14 April 2009 Time : 11:30Z : George Sky Aviation (Pty) Ltd : Robinson Helicopter Company 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 14 April 2009 the instructor and student took off from George Aerodrome (FAGG) to Mossel Bay Aerodrome (FAMO) on a training flight (conversion training flight). The training included the hydraulics off forward flight and hover. The instructor pilot (IP) mentioned that the student pilot (SP) brought the helicopter into hover position above threshold of runway 09 at FAMO into the direction of wind. The student pilot held a steady hover for a short period and then started losing control of the helicopter The IP instructed the SP to activate the hydraulic switch, however, and according to the IP, the SP froze on the controls. The hydraulic control is situated on the student s side of the cyclic controls According to the SP, the IP requested him to deactivate the hydraulic switch, which he did. The SP advised the IP that the aircraft was difficult to control, as the controls were hard. The IP advised the SP that they needed to have the hydraulic switch off for this part of the training. The SP then managed to get the helicopter into a hover momentarily before he lost control. The IP then instructed the student to activate the hydraulic switch at a height of approximately 20 feet above ground level (AGL). The SP managed to switch on or activate the hydraulic switch timeously before the helicopter impacted the ground. CA 12-12a 23 FEBRUARY 2006 Page 2 of 14

3 1.2 Injuries to Persons Injuries Pilot Crew Pass. Other Fatal Serious Minor None Damage to Aircraft The helicopter was destroyed during impact. See photo 1 below. Photo 1: Damage to helicopter 1.4 Other Damage None 1.5 Personnel Information Instructor pilot (IP) Nationality South African Gender Male Age 43 Licence Number * * * * * * * * * * Licence Type Commercial Licence valid Yes Type Endorsed Yes Ratings Instructors Medical Expiry Date 30 June 2009 Restrictions Corrective lens Previous Accidents None CA 12-12a 23 FEBRUARY 2006 Page 3 of 14

4 Flying Experience: Total Hours 245,1 Total Past 90 Days 43,5 Total on Type Past 90 Days 25,0 Total on Type 61, Student pilot (SP) Nationality South African Gender Male Age 55 Licence Number * * * * * * * * * * Licence Type Private Licence valid Yes Type Endorsed Yes Ratings None Medical Expiry Date 20 February 2010 Restrictions Corrective lens Previous Accidents None Flying Experience : Total Hours 142,6 Total Past 90 Days 1,0 Total on Type Past 90 Days 1,0 Total on Type 1,0 1.6 Aircraft Information Airframe Type R44 II Serial Number Manufacturer Robinson Helicopter Company Year of Manufacture 2006 Total Airframe Hours (At time of Accident) 629,8 Last MPI (Date & Hours) 27 January Hours since Last MPI 31,1 C of A (Issue Date) 31 August 2006 C of R (Issue Date) (Present owner) 30 August 2006 Operating Categories Standard Engine Type Lycoming IO 540-AE1A5 Serial Number L a Hours since New 629,8 Hours since Overhaul TBO not yet reached CA 12-12a 23 FEBRUARY 2006 Page 4 of 14

5 Figure1: Mass and Balance calculation at Take-off R44 II Weight and Balance WEIGHT LONG. ARM LONG. MOM. LAT. ARM LAT. MOM. Empty Weight 1510, , ,00 Pilot ,5 8712,00 +12,2 2147,20 Pilot Fore Passenger Fore Passenger Right Aft Passenger Right Aft Left Aft Passenger Left Aft Total Weight & Balance w/zero Usable Fuel , , ,4-2288, ,0 0,00-11,5 0, ,5 0,00 +12,2 0, ,5 0,00 +12, ,5 0,00-12, ,5 0,00-12, No Fuel Weight No Fuel Long. C.G. Long. Empty No Fuel Lat. C.G. Lat. Empty 1906,00 94, ,00-0,07-140,80 Main Tank 92,00 106, , Aux Tank 55,00 102, ,0 715 Total Weight & Balance w/take- Off Fuel Take-Off Weight Long. Full CG Long. Full Lat. Full CG Lat. Full 2053,00 95, ,00-0,33-667,80 CA 12-12a 23 FEBRUARY 2006 Page 5 of 14

6 Figure2: The helicopter s Centre of Gravity was within the limits. CA 12-12a 23 FEBRUARY 2006 Page 6 of 14

7 Figure3: Perceived Mass and Balance calculations at time of Accident R44 II Weight and Balance WEIGHT LONG. ARM LONG. MOM. LAT. ARM LAT. MOM. Empty Weight 1510, Pilot ,5 8712,00 +12,2 2147,20 Pilot Fore Passsenger Fore Passenger Right Aft Passenger Right Aft Left Aft Passenger Left Aft Total Weight & Balance w/zero Usable Fuel 0 44,0 0,00 +11,5 0, , ,00-10,4-2288, ,0 0,00-11,5 0, ,5 0,00 +12,2 0, ,5 0,00 0, ,5 0,00-12,2 0, ,5 0,00-12,2 0,00 No Fuel Weight No Fuel Long. C.G. Long. Empty No Fuel Lat. C.G. Lat. Empty 1906, , ,80 Main Tank 35,00 106, ,5-472,5 Aux Tank 25,00 102, ,0 325 Total Weight & Balance with Landing Fuel Landing Weight Long. Full CG Long. Full Lat. Full CG Lat. Full 1966,00 94, ,00-0,15-288,30 CA 12-12a 23 FEBRUARY 2006 Page 7 of 14

8 Figure4: Perceived Mass and Balance diagram at time of Accident CA 12-12a 23 FEBRUARY 2006 Page 8 of 14

9 Figure 5 In-Ground Effect of the helicopter According to figure 5 the helicopter could hover in ground effect up to a pressure altitude of 9700ft. CA 12-12a 23 FEBRUARY 2006 Page 9 of 14

10 Figure 6 Out-of-Ground effect of the helicopter According to figure 6 the helicopter could hover out of ground effect up to a pressure altitude of 6800ft. 1.7 Meteorological Information Weather information as obtained from the IP s questionnaires: Wind direction 012 Wind speed 5 kts Visibility Clear Temperature 25 Cloud cover Nil Cloud base Nil Dew point Unknown CA 12-12a 23 FEBRUARY 2006 Page 10 of 14

11 1.8 Aids to Navigation The aircraft was fitted with standard navigational instrument equipment. No defects were reported prior to or during the accident flight. 1.9 Communications The pilot was communicating his intentions on the frequency 124,20 MHz and no defects were reported prior to or during the accident flight Aerodrome Information Aerodrome Location Mossel Bay Aerodrome Co-ordinates S E Aerodrome Elevation 526 feet Runway Designations Runway Dimensions 1126 x x 18 Runway Used On threshold of Runway 09 Runway Surface Asphalt Approach Facilities Runway lighting 1.11 Flight Recorders The helicopter was not fitted with a cockpit voice recorder (CVR) or a flight data recorder (FDR), and neither was required by regulations to be fitted to this type of helicopter Wreckage and Impact Information The student pilot lost control of the helicopter while in a hover position at approximately 20 feet AGL. The helicopter then vertically impacted the ground, damaging the airframe, skids, tail boom and the main and tail rotors. See photo 1 p Medical and Pathological Information Not applicable Fire There was no evidence of a pre- or post-impact fire Survival Aspects The aircraft sustained minor damage to the cabin area, hence the accident was considered survivable. Both occupants were properly restrained with three-point safety harness. CA 12-12a 23 FEBRUARY 2006 Page 11 of 14

12 1.16 Tests and Research Information below is extracted from the helicopter aviation manual. Most helicopters use hydraulics to reduce the force needed to move the controls. Usually there is still a mechanical connection. In some helicopters there might not be a mechanical connection, or the forces acting on the controls may simply be too high for the pilot to overcome unassisted. Generally such helicopters will have redundant hydraulic systems. The Bell Jet Ranger/ Long Ranger and the Robinson R44 have boosted controls with mechanical backup. There are multiple ways such hydraulic systems can fail, but basically you can either have a failure where the entire system stops working or a failure where a part of the system stops working Information below is extracted from the Pilot s Operating Handbook R44 Raven II. Hydraulic system failure is indicated by heavy or stiff cyclic and collective controls. The controls will be normal except for the increase in stick forces. However, in this case the hydraulic did not fail; it was an induced failure Organisational and Management Information The training school had a valid ATO (aviation training organisation) approval (no. CAA 0012) The aircraft was maintained by aircraft maintenance organization (AMO) No. 1018, which was in possession of a valid AMO approval certificate The Regulator allowed the use of this helicopter for training, although it does not have a complete dual hydraulic control system. Furthermore, this control can only be accessed by the student and not by both pilots Additional Information None Useful or Effective Investigation Techniques None. 2. ANALYSIS 2.1 Man The SP was undergoing conversion training into a Robinson R44 helicopter when the accident occurred. The training required that the hydraulic switch be deactivated or switched off. Following the deactivation of the hydraulic system, the SP informed the IP of the stiffness of the controls. The IP explained the need to have the hydraulic system off. The SP then managed to get the helicopter on to a hover and held a steady hover for a short period before losing control. The instructor pilot instructed the student pilot to activate the hydraulic switch, which is situated only on CA 12-12a 23 FEBRUARY 2006 Page 12 of 14

13 the student s side of the cyclic control. The student did not activate the hydraulic switch timeously, resulting in the helicopter impacting the ground hard. 2.2 Machine According to available records, the helicopter was properly maintained and according to available documentation the helicopter had no recorded defect or malfunction that could have contributed to or caused the accident. Because the exercise being carried out required that the hydraulic switch be turned off, the pilot lost control as the controls became hard to manipulate The helicopter is used for training, although it does not have a dual hydraulic switch for both instructor and student. This switch was only on the SP cyclic control and in a position where the instructor could not reach it. 2.3 Environment The available information revealed that fine weather conditions prevailed in the area at the time of the flight and subsequent accident. Therefore it is concluded that weather was not a contributory factor to the accident The Regulator allowed the use of this helicopter for training although it does not have a complete dual hydraulic control system. Furthermore, this control can only be accessed by the student and not by both pilots. 3. CONCLUSION 3.1 Findings The instructor pilot had a valid commercial pilot licence (helicopter) and was properly rated at the time of accident The student pilot had a valid private pilot licence (helicopter and fixed wing) at the time of the accident According to available information the aircraft was properly maintained Weather was not a contributory factor to the accident The hydraulic switch was deactivated The student reported hardness of the controls The student pilot lost control of the helicopter The helicopter vertically impacted the ground hard, resulting in the helicopter being destroyed The helicopter had the hydraulic switch only on the SP cyclic control and not on the instructor's cyclic or in a position were both pilots could access it. CA 12-12a 23 FEBRUARY 2006 Page 13 of 14

14 3.2 Probable Cause/s Helicopter vertically impacted the ground hard following the pilot's loss of control during hover Contributory The failure of the instructor to react by taking over control of the helicopter as it can be flown with the hydraulic switch in the off position. 4. SAFETY RECOMMENDATIONS 4.1 None 5. APPENDICES 5.1 None. Report reviewed and amended by the Advisory Safety Panel on 16 March END- CA 12-12a 23 FEBRUARY 2006 Page 14 of 14