REPUBLIC OF KENYA MINISTRY OF TRANSPORT AND INFRASTRUCTURE AIR ACCIDENT INVESTIGATION INCIDENT REPORT BEECHCRAFT 200 REGISTRATION 5Y-EKO P.O. Box 52692-00200 Nairobi Telephone: 254-20-2729200 Fax: 254-20-2737320
SUMMARY OF INCIDENT OPERATOR: AIRCRAFT TYPE: MANUFACTURER: AIR TRAFFIC LIMITED BEECHCRAFT 200C HAWKER BEECHCRAFT YEAR OF MANUFACTURE: 1979 AIRCRAFT REGISTRATION: AIRCRAFT SERIAL NUMBER: 5Y-EKO BL-02 DATE OF REGISTRATION: 20 TH SEPTEMBER 2004 TYPE OF ENGINE: PRATT & WHITNEY PT6A-41 DATE OF INCIDENT: 13 th SEPTEMBER 2010 TIME OF INCIDENT: 1400 LOCATION OF ACCIDENT: TYPE OF FLIGHT: EGAL INTERNATIONAL AIRPORT, HARGEISA, SOMALILAND COMMERCIAL NUMBER OF PERSONS ON BOARD: 08 INJURIES: NATURE OF DAMAGE: CAPTAIN S FLYING EXPERIENCE: NONE BELLY, FLAPS, PROPELLER BLADES 7,000 HRS All times given in this report are Coordinated Universal Time (UTC). East African Local Time is UTC plus 3 hours. 3
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SYNOPSIS The AAID received notification of an aircraft incident that had occurred 13 th September 2010 at Egal International Airport, Hargeisa Somaliland. Because of logistical challenges there were no arrangements made to send investigators to Somaliland. This report is based on information and data obtained from the operator and other stakeholders. An aircraft, Beech 200 registration number 5Y-EKO, operated by Airtraffic Ltd made a partial wheel up landing on runway 24 at Egal International airport in Somaliland, at 17:00 local time. There were 8 persons on board including the pilot. All escaped unhurt from the serious incident. It is noted that the Kenya AAID took over the investigations as there was no functioning Aircraft Accident investigation agency Somaliland, the state of occurrence, at the time of the incident. Investigations were carried out by the AAID which included the Operator maintenance and flight operation records, and concluded that the aircraft landing gear system was serviced incorrectly thereby causing the gear extension system failure. The investigations which were carried out in accordance with accident investigation regulations and the provisions of the ICAO annex 13, was not intended to apportion blame or liability purposes but with the sole objective of prevention of accidents and incidents. The Cabinet Secretary, Ministry of Transport and Infrastructure, in accordance with regulation 18 of The Civil Aviation (Aircraft Accident and Incident Investigation) Regulations, 2009 authorizes the release of this report. 30 June 2014 5
ABREVIATION AMEL : Licensed Aircraft Maintenance Engineers AMO : Aircraft Maintenance Organization AOC : Air Operator s Certificate C of A : Certificate of Airworthiness C of R : Certificate of Registration ETA : Estimated Time of Arrival ETD : Estimated Time of Departure hrs : Hours IAS: indicated airspeed Kt: knot(s) lbs : Pounds ltr: litre(s) m: metres Nm: nautical mile(s) Psi: pounds per square inch Rpm: revolutions per minute TAS : True Airspeed TBO : Time Between Overhaul VFR : Visual Flight Rules 6
Table of Contents SUMMARY OF INCIDENT... 3 SYNOPSIS... 5 ABREVIATION... 6 Table of Contents... 7 1. Factual Information... 9 1.1. History of flight... 9 1.2. Injuries to persons... 11 1.3. Damage to Aircraft... 11 1.4. Personnel Information... 13 1.4.1. Pilot in Command... 13 1.5. Aircraft Information... 13 1.5.1. History of 5Y-EKO... 13 1.5.2. Equipment and Maintenance... 14 1.5.3. Weight and Balance... 16 1.6. Meteorological Information... 16 1.7. Navigation Aids... 16 1.8. Communications... 16 1.9. Flight Recorders... 17 1.10. Wreckage and Impact Information... 17 1.11. Medical and Pathological Information... 18 1.12. Fire... 18 1.13. Survival Aspects... 18 1.14. Test and Research... 18 1.14.1. Landing gear system gearbox assembly and motor.... 18 1.14.2. The right main mechanical landing gear actuator S/N 0500.... 19 1.14.3. The left main mechanical landing gear actuator S/N G297-11.... 20 1.15. Organization and Management Information... 22 1.16. Additional Information... 23 2. Analysis... 24 7
3. Conclusion... 25 3.1. Findings... 25 4. Probable cause... 26 5. Safety Recommendations... 27 APPENDIX (I) - Aircraft Status... 28 APPENDIX (II) - emergency procedures... 30 APPENDIX (III) landing gear Parts... 33 8
1. Factual Information 1.1. History of flight The aircraft was on a chartered flight from JKIA to Hargeisa and then Bosaso and then fly back to Hargeisa, Somaliland. The flight had departed JKIA at 0400Z for Hargeisa in the morning of 12 th September 2010. On 13 th September 2010 the aircraft took-off from Hargeisa at 0348 for Garowe with seven passengers, then took off for Bosaso at 0520Z landing at 0613Z before taking off for Hargeissa at 0635Z to land at 0804Z without any incident reported. The afternoon rotation flight was scheduled for similar routing from Hargeisa to Garowe, Bosaso and back to Hargeissa. After refueling the aircraft it departed at 0856Z with 7 passengers and landed in Garowe at 1020Z. At Garoe 2 passengers disembarked and 1 embarked on to the aircraft which then departed for Bosaso at 1037Z. The flight was cleared for flight level 190 by the Mogadishu Area control and upon getting in contact with the Bosaso Tower it started the descent. At 6nm from the runway 09, while at an aircraft speed of 140 IAS the landing gear got stuck on transit to extension. The flight was levelled off to 2000 AGL by the pilot while the co-pilot attempted to recycle the landing gear system. After several unsuccessful attempts to extend the landing gears the pilot 9
made a decision to fly back to Hargeisa where there were adequate facilities in case of an emergency. The pilot then made several unsuccessful attempts to extend the landing gear manually however the gears were still stuck almost half the way. At 17:00 local time with 30 minutes of fuel left in the wing tanks the pilot decided to land the aircraft, briefing the passengers on emergency procedures to be observed. On the landing roll on runway 24 the gears collapsed and the aircraft swerved on its belly to a stop after veering off to the right side of the runway. All the 8 occupants were evacuated from the aircraft immediately with none of them sustaining injury. The aircraft flaps, propeller blades and the underbelly were damaged as a result of the partial wheel up landing. The last flight of 5Y-EKO (Garowe Bosaso Hargeisa) 10
1.2. Injuries to persons There were no injuries on the crew and passengers. Injuries Crew Passengers Total in aircraft Fatal 0 0 0 Serious 0 0 0 Minor 0 0 0 None 2 6 8 TOTAL 2 6 8 Table 1: Summary of all onboard 1.3. Damage to Aircraft Damaged aircraft underbelly 11
A section of the belly skin and internal structures (between station 326.7 to station 273.52) were damaged. Both left and right hand side propeller blades were damaged from striking on the ground during the landing roll. 12
1.4. Personnel Information 1.4.1. Pilot in Command The pilot in command was a 39 yr old male who held an airline transport pilot license. The pilot was examined medically for his ATPL 1 st class certificate by a KCAA approved examiner on 31 st March 2010. The pilot had 6596 total flying hrs, of which 4,288 hrs as PIC and 1,577 as co-pilot, at the time of license renewal (7 April 2010). He also had accumulated 4,340 hrs of instrument flying at the time. 1.5. Aircraft Information 1.5.1. History of 5Y-EKO The aircraft, registration mark 5Y-EKO and serial number BL- 02, was manufactured by Raytheon Aircraft Company (now Hawker Beechcraft Corporation) of the USA in 1979. The aircraft was registered in Kenya as 5Y-EKO on 20 September 2004 and issued with a certificate of airworthiness. Power Plant The aircraft was powered by two Pratt and Whitney Canada PT6A-41 engines and two Hartzell model propellers. Detailed status of the landing gear components as at 22 September 2010, are given in the status table in appendix 1. 13
1.5.2. Equipment and Maintenance The aircraft was equipped for instrument flight, by virtue of installed equipment such as transponders, dual VHF omnidirectional range receivers (VOR), distance measuring equipment (DME), low frequency automatic direction finding equipment (ADF), an emergency locator transmitter (ELT) and global positioning systems (GPS). The aircraft was maintained by Airtraffic Limited, a Kenya Civil Aviation Authority approved AMO. The airworthiness certificate was issued by the KCAA after the aircraft underwent major maintenance. The C of A was to expire on 30 June 2011. A radio station license was issued by the Communication Commission of Kenya at the same time, on recommendation of the KCAA. The radio equipment had been maintained as part of the scheduled maintenance and certified for release. The aircraft underwent schedule maintenance inspection in the preceding 1 year as follows; Inspection phase Airframe hours Date of inspection Phase 2 23, 415.44 22/11/2009 Phase 3 23, 615.84 15/03/2010 Phase 4 23, 799.84 04/06/2010 14
It had flown a total of 24,024.40 hrs and had 18,265 total landings as at 11 November 2010 when it last flew back to maintenance base after the landing incident. The nose and main landing gear components hours as at 11 November 2010 are provided in the table in appendix 1. The engines installed had the following hours at the last renewal of its C of A: Engine No. 1 Engine No. 2 Engine type PT6A-41 PT6A-41 Serial no. RC0008 RC0029 Total time: 2853.29 3053.81 TSO 598.58 1113.81 The Hartzell model propellers installed had the following hours at the renewal of its C of A: Serial numbers BU-A27874 BU-A20728 Total propeller hrs. NK 4963.34 Time since O/H 1271.42 936.41 Date of instlln. 10/02/2009 20/02/2009 15
1.5.3. Weight and Balance The aircraft was last reweighed on 13 June 2006 and was next due to be reweighed on 13 June 2011. There was no record of modifications that could influence change in the basic weight of aircraft since the last re-weigh date. 1.6. Meteorological Information The weather was not a factor in this incident. 1.7. Navigation Aids N/A for this accident 1.8. Communications No communication problems were encountered. All communications equipment available at the tower operated normally. There was no sound recording equipment. 16
1.9. Flight Recorders The recorders are not fitted in this type of aircraft and are not a requirement in the existing regulations. 1.10. Wreckage and Impact Information 5Y-EKO after making a belly landing and veering off the runway in Hargeisa in Somalia 17
1.11. Medical and Pathological Information This was not a factor in this accident 1.12. Fire There was no fire before or after the accident. 1.13. Survival Aspects The incident was survivable. 1.14. Test and Research The failed landing gear components retrieved from the aircraft and were then sent to the FAA Wichita ACO office, USA. The following components were received for testing and examination: Landing gear system gearbox and motor assembly Left main mechanical landing gear actuator S/N 0500 Right main mechanical landing gear actuator S/N G297-11 1.14.1. Landing gear system gearbox assembly and motor. The gearbox position switches were found shattered and laying in the bottom of the shipping container. The gearbox was operated manually by engaging the input sprocket directly with the output end of the internal clutch assembly. This action simulated pulling up on the emergency 18
engage handle located on the cockpit floor and turning it clockwise then cycling the cockpit lending gear extend ratchet handle in the cockpit. The gearbox output drives were driven, simulating manual gear extension, successfully. The gearbox drive motor and clutch were not examined. Note: The HBC Component Maintenance Manual with Illustrated Parts List P/N 98-36381E, Section 32-31-01, will be referenced. Specific actuator parts will be referenced using the manual Section 32-31-01, Figure 2, Illustrated Parts Breakdown-Main Gear Actuator (page 16). Specific assembly steps (manual pages 7 through 16 will be referenced. 1.14.2. The right main mechanical landing gear actuator S/N 0500. The actuator nut (item 32) was successfully driven (extension and retraction direction) by manually rotating the pinion gear (item 27). The actuator operated smoothly. The actuator was disassembled and the following items examined for condition: The actuator nut (item 32) The actuator screw (item 3) The lower (thrust) bearing (item 39) orientation The screw housing (item 13) The pinion gear (item 27) The threads on the actuator nut and screw were in good condition and lubricated. The lower thrust bearing was installed (thrust orientation) correctly, and the bearing rotated smoothly. The screw housing gear was in good condition, and the pinion gear was in good condition. The housing was lubricated. 19
1.14.3. The left main mechanical landing gear actuator S/N G297-11. The actuator nut (item 32) could not be driven (extension and retraction direction) by manually rotating the pinion gear (item 27). After less than one turn of the pinion gear the actuator became locked. The actuator was disassembled and the following items examined for condition: The actuator nut (item 32) The actuator screw (item 3) The lower (thrust) bearing (item 39) orientation The screw housing (item 13) The pinion gear (item 27) The threads on the actuator nut and screw were in good condition and lubricated. The lower thrust bearing was not installed in the correct orientation in accordance with assembly instruction Step C located on page 7. The bearing orientation step is highlighted by a Caution stating that the bearing must be installed correctly to resist thrust. The bearing inner race was partially separated from the balls and outer race, preventing the bearing from rotating. The screw housing gear was not in good condition; multiple gear teeth were separated and the separated gear teeth were found in the housing grease. There was evidence of scoring on the end of the screw housing on which the lower bearing (item 39) mounts which would confirm the bearing inner race not being able to rotate. The pinion gear was not in good condition; evidence of debris passage (dents and gouges) through multiple gear teeth was present. There was a piece of a separated gear tooth from the screw housing gear lodged between two pinion teeth. The lodged gear tooth would prevent the actuator nut from being moved. Close examination of the pinion gear revealed evidence of the screw housing gear teeth top surface contacting the bottom of the pinion gear gullies. A photograph detailing the examination is attached in the appendix section. The results of the submitted landing gear components examination revealed the following: 20
The gearbox could be operated manually to extend the landing gear. The right main mechanical landing gear actuator could be operated manually to extend and retract the nut. The left main mechanical landing gear actuator could not be operated manually to extend and retract the nut. The left actuator lower thrust bearing was not installed in the correct orientation and was jammed due to inner race partial separation from the balls and outer race. The left actuator screw housing gear had multiple separated gear teeth. The left actuator pinion gear had a gear tooth lodged between two gear teeth. The lodged gear tooth would have locked the left actuator from rotating. The pinion bearing and screw housing gear teeth damage was the result of the lower bearing installation orientation; backwards, which resulted in the screw housing gear and pinion gear end play not being maintained. Both actuators were well lubricated. Gearbox and motor assy. Main Landing gear actuators The landing gear components sent for testing and examination 21
1.15. Organization and Management Information Airtraffic Limited is a duly incorporated company under the Laws of Kenya. A visit to the company yielded the findings below: The organization holds an approval certificate granted by the Kenya Civil Aviation Authority to carry out scheduled and unscheduled maintenance inspections on Beech 200 series, Beech 1900 series and Dornier 228 series aircraft. The scope of approval given was pegged on the company capability as per the time of the audit inspection. Maintenance and Servicing manuals were found adequate to cover for the fleet in the company. The tooling was found adequate for routine aircraft servicing. The equipment seen at the workshop was limited for small maintenance service tasks and not sufficient for the servicing of the landing gear components. It was noted that the maintenance staff at the Hangar floor were lacking the necessary training and experience on the aircraft fleet the company operates. The few supervisory staff had the necessary training however the adequate supervision required for servicing of the aircraft landing gear components could not be proven. 22
1.16. Additional Information An interview with the Hangar floor personnel revealed the lack of training and experience in the Beech 200 maintenance. Most of the Hangar staff had recently been recruited in the organization. Observance of maintenance procedures as stipulated in the components maintenance manuals were lacking. The company certifying staff was qualified for the Beech 200 however; recurrent training on type was needed. The aircraft maintenance schedules were well observed. 23
2. Analysis Pilot The pilot made numerous attempts to recycle the landing gear system manually following the emergency gear extension procedures without success. The emergency landing gear manual extension procedures used by the pilot are attached in appendix II. Maintenance During the servicing of the landing gear components, the parts were lubricated with proper grease and assembled. In the components maintenance manual (CMM), the steps for the assembly of parts are clearly stipulated with additional caution where appropriate. For the assembly of the lower thrust bearing, the highlighted caution stating the bearing must be installed correctly to resist thrust was not followed during the assembly. The lower thrust bearing therefore was installed in the wrong orientation resulting in the bearing inner race separating from the outer race and balls, which then prevented the rotation of the bearing. A broken left actuator pinion gear tooth lodged between the 2 meshing gears prevented movement of the actuator to extend or retract the landing gears. 24
3. Conclusion 3.1. Findings a) The pilot was qualified to conduct the flight. b) The pilot was familiar with the route c) The personnel who serviced the landing gear components were not trained on the aircraft and landing gear system. d) The personnel who serviced the landing gear components were not adequately supervised by the certifying staff. e) The technician who installed the actuator did not follow the procedures as outlined in the maintenance manual. 25
4. Probable cause The landing gear system jam was caused by the failure of the left main gear actuator lower thrust bearing. The failure of the actuator lower thrust bearing resulted from an incorrect (wrong orientation) installation after servicing. 26
5. Safety Recommendations KCAA to enhance its oversight role on the operator to ensure adherence to the AMO scope of approval and aircraft maintenance procedures. 27
APPENDIX (I) - Aircraft Status 28
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APPENDIX (II) - emergency procedures 30
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APPENDIX (III) landing gear Parts Landing gear defective parts 33