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0806

1. ec 4171 3200 3200 NIL 971 0 00030 BEN _i AN ASPH 33 57 35 429 S 3200 SE 3200 3200 NIL 343 2 00030 aoe 135 T 33 57 40 957 S i 018 35 50 890 E L 34 315 T EFF 29 JUL 10 33 58 20 144 S _018 36 37 564 E 1 11 Flight recorders 1701 1701 1701 1701 NIL Da 0 00140 PCN ASPH 1701 1701 1701 1701 NIL E 0 00140 SOUTHAFRICAN Vas CHL ALIRON AUTHORITY eas 7 32 FINXIU 1 11 1 The aircraft was not equipped with a flight data recorder FDR or a cockpit voice recorder CVR nor was it required by regulation to be fitted to this type of aircraft CA 12 12b 25 MAY 2010 Page 10 of 25 1 12 Wreckage and impact information 1 12 1 Following landing on runway 19 the pilot turned right onto taxiway Charlie to vacate the runway when the nose gear collapsed and the propeller struck the asphalt surface The aircraft came to a halt in a nose down attitude on the taxiway A photo of the aircraft being recovered with the nose gear retracted 1 13 Medical and pathological information 1 13 1 Not applicable 1 14 Fire 1 14 1 There was no pre or post impact fire CA 12 12b 25 MAY 2010 Page 11 of 25 1 15 Survival aspects 1 15 1 This incident was considered survivable All occupants on board the aircraft were properly restrained at the time by making use of the aircraft s safety harnesses 1 16 Tests and
2. NDB runway lights PAPIs ILS Aerodrome status Licensed License validity 1 September 2009 to 31 August 2010 CA 12 12b 25 MAY 2010 Page 9 of 25 AERODROME CHART 33 58 16 93 S ELEV 151 33 58 S 33 59 S 19 CHANGE Holding Positions Circuit CAPE TOWNATIS 127 00 018 36 15 45 E APN 422 65 ELEV ALT amp HGT IN FEET DIST IN METERS BRG ARE MAG VAR 25 W 2009 SCALE 1 30 000 0 ALS ILS LOC WY OF PALS CAT 1i PALS CAT i 3 2 16 165 T 33 59 15 846 S 018 36 00 181 E 018 36 32 013 E SMC 121 90 TWR 118 10 CAUTION 1 Do not confuse THR 16 for THR 19 when taxiing on TWY A1 for take off on RWY 19 2 Avoid overfiying Tygerberg Hospital 3NM North of AD when taking off from RWY 01 amp 34 3 PAPI RWY 19 must not be used beyongd SNM from THR 4 For the ASMGCS Project a 30m 98 steel TWR has been at 33 57 54 25S 018 36 40 73 E ELEV 263 HGT 99 a ts GP l Dss 4 x RWY s CAPE TOWN VOR DME 115 7 CH 104X CW z 33 58 10 82 S 018 36 18 19 E 146 TAXIWAYS 23m 75 WIDE ILS GP 335 o RWY 01 REDL ae WHITE ae i Ne eet KSI 109 1 le es eee RWY 19 WHITE RED 018 37 E CAPE TOWN INTL FACT constructed on the AD next to the SAAF hangar This TWR is located TORA TODA ASDA LDA SWY CWY SLOPE SURFACE BEARING m m m m m m STRENGTH CIRCUIT
3. NO NUT PLATES FITTED TO A C BUT ATTACHMENT NUT AND BOLTS SATISFACTORY SHIMMY DAMPER SEAL REPLACED SERVICED AND TESTED SATISFACTORY 1 7 Meteorological information 1 7 1 Weather information was obtained from the pilots questionnaire and ATC Wind direction Wind speed Visibility Cloud cover Cloud base 1 8 Aids to navigation 1 8 1 The aircraft was equipped with standard navigational equipment which was serviceable and functioning accordingly at the time of the incident CA 12 12b 25 MAY 2010 Page 8 of 25 1 9 Communications 1 9 1 The pilot was in radio contact with Cape Town air traffic control ATC on the VHF frequency 118 1 MHz at the time of the incident as the aircraft was in the process of vacating runway 19 He immediately informed ATC of the occurrence once the nose landing gear collapsed ARFF personnel responded accordingly following the activation of the crash alarm by ATC 1 10 Aerodrome information 1 10 1 Aerodrome details Aerodrome location 7 nm SE of the city of Cape Town Aerodrome co ordinates South 33 5816 93 East 018 3615 45 Aerodrome elevation 151 feet above mean sea level AMSL Runway designations 01 19 16 34 Runway dimensions 3 200 x61 m 1701 x46m Runway used 19 Threshold elevation 147 feet AMSL Runway slope Downslope of 0 03 Runway grooved No Runway surface Asphalt Approach facilities VOR DME
4. Sheet 1 CA 12 12b 25 MAY 2010 Page 21 of 25 NOSE LANDING GEAR ACTUATOR REFERENCE MODEL 172RG SHOWN SL t OTHER MODELS TYPICAL ri NOSE LANDING GEAR REFERENCE Figure 1 Down lock Actuator Pin Inspection Sheet 1of 2 CA 12 12b 25 MAY 2010 Page 22 of 25 Accomplishment Instructions Remove and Disassemble Nose Gear Actuator From Airplane Jack the airplane off the ground in accordance with the airplane service manual With Master Switch in the OFF position and the hydraulic pump circuit breaker disengaged select GEAR UP on the gear handle Turn the Master Switch to the ON position and momentarily engage hydraulic pump circuit breaker When gear begins to retract disengage hydraulic pump circuit breaker and place Master Switch to the OFF position Disconnect all electrical power from the airplane Attach maintenance warning tags to the battery connector and external power receptacle stating WARNING DO NOT CONNECT ELECTRICAL POWER MAINTENANCE IN PROGRESS Disconnect and remove the nose landing gear actuator assembly from the nose landing gear bearing end and fuselage aft attach end Cap or plug lines and fittings Refer to airplane service manual Disassemble the nose gear actuator to gain access to the bearing end Refer to airplane service manual Drive out existing roll pins one per side securing lock pins and bearing end Remove and d
5. Z South African Standard Time is UTC plus 2 hours Purpose of the Investigation In terms of Regulation 12 03 1 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 1 1 1 The pilot accompanied by two passengers departed from Cape Town International aerodrome FACT at 1045Z on a local private flight After being airborne for approximately one hour and forty five minutes they returned to FACT for the landing CA 12 12b 25 MAY 2010 Page 2 of 25 1 1 2 1 2 1 3 1 3 1 The prevailing wind at the time being from the south east the pilot was cleared to land on runway 19 by air traffic control ATC Prior to landing the pilot selected the landing gear down and normal operation was confirmed by the green gear down light coming on in the cockpit The pilot indicated that he touched down on the main landing gear and kept the nose landing gear off the ground until elevator effectiveness was lost Approximately 30 metres after the nose wheel had touched down the pilot noticed that the nose started dropping and the propeller struck the runway surface several times He immediately appl
6. lock engagement It does not require the down lock pins to be inspected CA 12 12b 25 MAY 2010 Page 6 of 25 MODEL 172RG SERVICE MANUAL NOSE GEAR 4 Wheel sccccuscscnvcreseseowscsvenston rere rer yr Ocbesvabsteteesavenedsecoves 2 BeaniGSesccsnsnepsendccsveussexu ebrtsccesssesee ee vbemravesenrastssessessyy S WH cssssneversvesensswscease s OU OCR eee een naedenesnenenncsecceonetacecduce 4 Shock strut service as required 0s5seeues cevencsasrecnene canedpecnes saamge 5 Shimmy dampener service as required s ssessss opeceussvcncansesvssccenas RETRACTION SYSTEM go NOTE When performing an inspection of the landing gear retraction system the aircraft must be placed on jacks and an external power source of at least 60 amps should be used to prevent drain on the airplane s battery when operating the system Operate the landing gear through five fault free cycles 20 oe voncvcdusee NOTE Less than 6 seconds to extend Less than 8 seconds to retract Check main gear downlock engagement ss ss s IIA T Check main gear strut to pivot atachMent essessunssanse E NRE AE T Check adjustment and operation of the main gear up and down indicator switches nose gear up and down indicator switches and nose gear squat switch Check indicator for proper operation se2cecverenncasuncanscrscszesaces ovens Check nose gear doors for at last inch clearance with any part of the landing ge
7. 5 3 653 1 Nose gear failure propeller strike Source Aircraft Airframe Logbook pages 4 and 5 CA 12 12b 25 MAY 2010 Page 5 of 25 The airframe logbook contains the following entry with regard to the repairs pertaining to the nose gear failure incident on 18 May 2005 Type of maintenance performed Propeller Strike Following parts replaced after landing incident 7 Fork end Part number 0770 0770 2 Damper Part number 1442114 1 3 Clamp Part number 2243028 1 Sheet metal repairs carried out to nose gear wheel well Signed off by AMO No 221 on 5 October 2005 The propeller logbook contains the following entry in the form of a CRMA The propeller McCauley 32D 34C 220B Serial No 000385 had been overhauled in accordance with the relevant manual No 780630 REV 6 SPM 100 1 BOM 100 1 REV 1 and Appendix 1 of the General Maintenance Rules Pages GMR 66 amp GMR 67 Section 5 1 Major Replacements New blades above serials 04 1950 Mc Prop Repairs carried out Standard Overhaul Procedures 1 6 3 Nose gear inspection During the maintenance inspection which was certified on 30 June 2010 the nose landing gear of the aircraft was inspected in accordance with the aircraft manufacturer s service schedule see attached document below which was extracted from the work pack The inspection requires a detailed inspection of the nose landing gear which include checking for main gear down
8. SOUTH AFRICAN we Section division Accident and Incident Investigation Division Form Number CA 12 12b CIVIL AVIATION AUTHORITY AIRCRAFT SERIOUS INCIDENT REPORT AND EXECUTIVE SUMMARY CA18 3 2 0806 ZS PMY Date of Incident 10 09 2010 Time of Incident 1245Z Registration Type of Aircraft Cessna 172RG Aeroplane Type of Operation Private Pilot in command Licence Type Commercial Age Licence Valid eae Flying Total Flying Hours 246 2 Hours on Type xperience Last point of departure Cape Town International Aerodrome FACT Next point of intended landing Cape Town International Aerodrome FACT Location of the incident site with reference to easily defined geographical points GPS readings if possible Cape Town International Aerodrome Taxiway Charlie Meteorological Information Surface wind 135 15 kt temperature 17 C visibility 10 km No of people killed o Synopsis The pilot accompanied by two passengers departed from Cape Town International Aerodrome on a local private flight After being airborne for approximately one hour and forty five minutes they returned to FACT for the landing No of people injured Number of people on board 1 2 Prior to landing the pilot selected the landing gear down and normal operation was confirmed by the green gear down light illuminating After approximately 30 m the nose landing gear had touched down the pilot not
9. ar during operation and jor proper fit when closed soowewe 28S Sie hawaii ewe 1 6 4 Certificate relating to maintenance of an aircraft CRMA The certificate relating to maintenance of an aircraft see attached document below that was issued for the aircraft ZS PMY following the last maintenance inspection prior to the accident flight reflects that the nose gear inspection was carried out as required and that no faults were found The system operated satisfactorily the maintenance inspection requires five fault free cycles of the landing gear CA 12 12b 25 MAY 2010 Page 7 of 25 Aircraft Cessna Engine Prop Mc Cauley CERTIFICATE RELATING TO bia MAINTENANCE OF AN AIRCRAFT Section Airframe Page 1 Make Model Job 1148 Hours N A Cycles 0 AIRFRAME MPI CARRIED OUT IN ACCORDANCE WITH THE MANUFACTURERS INSPECTION SCHEDULE AND SACATS GMR 36 ISSUE 24 PITOT STATIC CARRIED OUT AS REQUIRED BY AIRCRAFT INSTRUMENTS FIRE EXTINGUISHER CHECKED AND SERVICED AS REQUIRED SEAT BELTS CHECKED SEAT BELTS REMANUFACTURED AS REQUIRED PER ATTACHED CRMA FIRST AID BOX CHECKED AND SERVICED AS REQUIRED PROPELLER REMOVED AND INSTALLED AFTER HALF LIFE INSPECTION 3 YEAR 1000 HOUR ELEVATOR TRIM TAB ACTUATOR INSPECTION CARRIED OUT AS REQUIRED RE FITTED AND RE RIGGED OPERATION SATISFACTORY NOSE GEAR INSPECTION CARRIED OUT AS REQUIRED NO FAULT FOUND OPERATION SATISFACTORY
10. ated on this aircraft The service bulletin is attached to this report as Annexure A CA 12 12b 25 MAY 2010 Page 12 of 25 1 17 Organisational and management information 1 17 1 This was a private flight The aircraft was hired by the pilot from a flying club for his private use under a hire and fly agreement 1 17 2 According to available records the aircraft maintenance organisation AMO that certified the last MPI prior to the accident was in possession of a valid AMO Approval certificate that was issued by the regulating authority 1 18 Additional information 1 18 1 Landing gear system Quoted from Cessna 172RG Service Manual General Description Retraction and extension of the landing gear is accomplished by a hydraulically powered system integrated with electrical circuits which help control and indicate gear position Retraction and extension of the landing gear incorporates a nose gear actuator and two main gear actuators which control the main gear struts through a sector gear arrangement The nose gear doors are mechanically operated The doors are closed with the gear retracted and are open with the landing gear extended The main gears have no doors Hydraulic fluid is supplied to the landing gear actuating cylinders by an electrically powered power pack assembly located in the cabin forward of the center console The hydraulic reservoir is an integral part of the power pack assembly Gear selection i
11. ear actuator be inspected Cessna Service Bulletin SB SEB95 20 was an option by the aircraft manufacturer to the applicable affected aircraft owners which indicates that the manufacturer had introduced an improvement to the original design by issuing the SB and informed all aircraft owners that failure to comply with the SB could result in the nose landing gear not locking in the down position and collapsing By adhering to the SB the risk of an unforeseen nose landing gear collapse could be avoided although no guarantees could be associated with compliance with such a bulletin The aircraft manufacturer issues an SB in the interest of safety but has no control over the operational aspects to which such an aircraft is exposed while in service which could include landing and taking off from licensed and unlicensed runways landing strips aerodromes hard landings excessive braking and exceeding the design envelope limitations of the aircraft especially owing to maximum allowable take off and landing weight This incident was however not an isolated occurrence According to the SACAA accident incident database a similar type of occurrence was recorded on 28 July 2006 when the nose landing gear of a Cessna T210K collapsed during landing The CA 12 12b 25 MAY 2010 Page 16 of 25 2 3 2 4 3 1 3 investigation concluded that one of the NLG actuator down lock pins had failed and as a result the nose landing gear collapsed dur
12. from jacks and make an entry in the airplane logbook stating CA 12 12b 25 MAY 2010 Page 24 of 25 this service kit has been installed DRILL 5 64 0 0781 INCH DIAMETER HOLE 2 REQUIRED MS16562 20 ROLL PIN 2 REQUIRED 1280600 BEARING END REFERENCE 1290009 3 DRILL TOOL 1 REQUIRED ALIGNMENT GROOVE AND INDEX MARK peTAIL B REFERENCE ILL TOOL PLACED ON BEARING END MS16562 20 ROLL PIN REFERENCE 1290009 2 PIN 2 REQUIRED NOTE ROTATIONAL TOLERANCE TO THE ALIGNMENT MARK IS APPROXIMATELY 5 IT MAY DETAIL BE NECESSARY TO HEAT THE BEARING END AND OR NEW HOLE DRILLED DRILL TOOL REMOVED COOL THE PINS TO FIT THEM TOGETHER AS THEY ARE NOMINALLY AN INTERFERENCE FIT Figure 1 Down lock Actuator Pin Replacement Sheet 2 CA 12 12b 25 MAY 2010 Page 25 of 25
13. iced that the propeller made contact with the runway surface several times He immediately applied back pressure to the control column to raise the nose of the aircraft Following this intervention the nose wheel touched down for a second time without any further problem and the aircraft continued to roll down the runway However as the pilot turned right onto taxiway Charlie in order to vacate runway 19 the nose landing gear collapsed and the propeller struck the asphalt surface The aircraft came to rest in a nose down attitude whereafter the pilot secured the aircraft and the three occupants disembarked from the aircraft unassisted Probable Cause The nose landing gear NLG collapsed during taxiing due to the failure of one of the NLG actuator down lock pins during operation Release IARC Date Date CA 12 12b 25 MAY 2010 Page 1 of 25 SOUTH AFRICAN Form Number CA 12 12b Ty Section division ECHON AIVISIO Accident and Incident Investigations Division ior fz eects AIRCRAFT SERIOUS INCIDENT REPORT AUTHORITY Name of Owner Operator Manufacturer Model Nationality Registration Marks Place Date Time The Cape Flying Partnership Cessna Aircraft Company 172RG South African ZS PMY Cape Town International Aerodrome 10 September 2010 12452 All times given in this report are Co ordinated Universal Time UTC and will be denoted by
14. ied back pressure to the control column and managed to raise the nose of the aircraft Once the nose wheel settled down on the runway for the second time he continued to taxi down the runway without any further problem As they turned right onto taxiway Charlie in order to vacate runway 19 the nose landing gear collapsed and the propeller struck the asphalt surface The pilot then proceeded to secure the aircraft According to the pilot there was no gear unsafe audio warning that was activated during the sequence either while they were on the runway or as the nose landing gear collapsed during the turn Nobody on board the aircraft was injured and the three occupants disembarked unassisted The aircraft was recovered by aerodrome rescue and fire fighting ARFF personnel as it was obstructing blocking the runway and was taken to a nearby maintenance facility Injuries to persons Injuries Pilot Crew Pass Other Fatal Serious Minor z None 1 2 Damage to aircraft The aircraft sustained substantial damage when the nose landing gear collapsed CA 12 12b 25 MAY 2010 Page 3 of 25 Visible damage to the propeller Visible damage to the nose gear doors 1 4 Other damage 1 4 1 No other damage was caused 1 5 Personnel information 1 5 1 Pilot in command Nationality South African Gender Male Age 19 Licence number sea
15. ing the landing roll Although not the same model of aircraft the one in question the operation of the landing gear system was the same It was found that Cessna Service Bulletin SEB95 20 was incorporated on the Cessna T210K yet the nose landing gear collapsed The down lock pins on the nose landing gear actuator are on condition items and if not properly inspected maintained they might fail in operation without prior notice Although this aircraft was subjected to a maintenance inspection shortly prior to this failure and only 7 flying hours were recorded it is considered highly unlikely that the fatigue cracking that might have been present at the time would have been picked up by maintenance personnel as it was not a schedule inspection requirement to inspect these pins for cracks nor to have them subjected to any form of non destructive crack testing procedure during maintenance The pin was found to have failed in fatigue Available information indicates that this aircraft was involved in four previous incidents related to the nose landing gear tabled in paragraph 1 6 2 of this report over the period 20 April 1982 to 18 May 2005 None of these occurrences appears on the SACAA accident incident database even though it would appear that the aircraft sustained substantial damage during these incidents The aircraft had been in service for nearly five years following the last repair with 998 30 flying hours being logged subsequently It was ho
16. is aircraft therefore the risk of this known problem was not mitigated 4 SAFETY RECOMMENDATIONS 4 1 It is recommended that the Director of Civil Aviation in collaboration with the Airworthiness Division introduce a life limit or non destructive test procedure at regular intervals on the down lock pins to ensure that safety is not compromised and to prevent a re occurrence of this nature 5 APPENDICES 5 1 Annexure A Cessna Service Bulletin SEB95 20 dated December 29 1995 Report reviewed and amended by the Advisory Safety Panel 18 January 2011 END CA 12 12b 25 MAY 2010 Page 18 of 25 ANNEXURE A Cessna Service Bulletin SEB95 20 Shortened version Effectively Models 172RG F182RG R182 TR182 210 T210K L M N R P210N R NOTE The above list of models is a basic summary of the models affected by this Service Bulletin which basically includes all single piston engine Cessna models with retractable landing gear Purpose Reports have been received of the nose landing gear actuator down lock pins cracking and or failing The pins have failed at a circumferential groove that is used to secure the pin in the actuator bearing end To assist in preventing this condition from occurring an inspection should be accomplished to determine the security of the down lock pins Actuators with down lock pins that are found to be loose should have the pins replaced according to the criteria in this service b
17. iscard the existing 1280209 1 lock pins from the bearing end Refer to airplane service manual Inspect Bearing End For Out of Tolerance Condition Inspect the lock pin holes in the bearing end for excessive wear and or elongation Measure the diameter of the holes with a micrometer The maximum allowable hole diameter is 0 3760 inch If either of the holes in the bearing end are out of tolerance replace the bearing end and proceed to Step 3 1 If both of the holes are within tolerance proceed to step 3 Install the 1290009 2 Lock Pins Insert the 1290009 3 drill tool in pin hole on one side of bearing end Refer to Figure 1 Sheet 2 Detail B CA 12 12b 25 MAY 2010 Page 23 of 25 4 Secure the drill tool to the bearing end by inserting a 5 64 inch rod or equivalent sized drill bit through drill toll into the existing roll pin hole NOTE Drill toll contains three holes The center hole is used to guide the drill bit when boring a new hole in the bearing end The left and right holes are used to position the tool in the bearing end Placement of the 5 64 inch rod in the left or right hole is dependent on which side of the bearing end is being drilled With drill toll in place drill a 5 64 0 0781 inch diameter hole through the center line hole in the drill tool all the way through the bearing end Take care to drill with minimum pressure so the drill bit does not wander Refer t
18. o Figure 1 Sheet 2 Detail B Using the alignment groove on the 1290009 3 drill tool place a mark on teh bearing end for aligning the pin Remove the drill tool from the bearing end Repeat steps 3 A thru 3 E on the other side of the bearing end Insert the new 1290009 2 pins in the bearing end Refer to Figure 1 Sheet 2 Detail C Ensure the alignment slot in the pin matches with the alignment mark on the bearing end created in step 3 D Press the pins in so they protrude through the inside bearing surface 0 325 inch 0 005 inch This will ensure the down lock assembly does not contact the pins when the actuator is retracted NOTE The hole in the new pin is larger than the 5 64 inch hole drilled in step 3 C This is to allow for slight misalignment of the pin with the hole It may be necessary to heat the bearing end and or cool the pins to fit them together as they are nominally an interference fit Secure the pins with MS16562 20 roll pins inserted through the newly drilled 5 64 inch hole Reassemble the actuator using new o rings Refer to airplane service manual Reinstall the nose landing gear actuator using retained hardware and new MS24665 134 cotter pin Refer to airplane service manual Rig the nose landing gear per the airplane service manual Restore electrical power and cycle the gear up and down a minimum of three times to ensure landing gear has been properly rigged Remove airplane
19. research 1 16 1The aircraft was recovered from the taxiway to a maintenance facility where it was placed on jacks The damaged nose landing gear doors were removed and the hydraulic fluid level was confirmed to be within the normal operating limit range No leaks on the system were visible The landing gear of the aircraft was subjected to detailed inspection after which it was decided to cycle the gear The landing gear extended normally but the nose landing gear would not lock down into the down lock position Nevertheless the green gear down warning light went out The landing gear safe light was tested and found serviceable The audio warning system although soft was operational Upon further inspection it was found that one of the NLG actuator down lock pins had shifted against the actuator shaft preventing the locking mechanism from achieving its down lock position On further inspection the nose landing gear down lock actuator pins were examined and one of the pins was found to have failed see photo below in fatigue causing the nose landing gear not to lock down properly within the down lock hook mechanism A view of the actuator with the down lock pins installed A view of the failed down lock pin contained in the housing 1 16 2 Cessna issued a Service Bulletin SEB95 20 dated December 29 1995 with regard to the nose landing gear actuator down lock pin inspection Maintenance records indicate that SEB95 20 was not incorpor
20. s accomplished manually by moving a gear selector handle located immediately left of the center in the switch panel It is necessary to pull out on the gear selector to move the handle up or down For emergency extension of the gear the selector handle must be in the DOWN position before the hand pump will energise the system A pressure switch is mounted on the power pack The switch opens the electrical circuit to the pump solenoid when pressure in the system increases to approximately 1500 psi The pressure switch will continue to hold the electrical circuit open until pressure in the system drops to approximately 1000 psi This will occur whether the gear selector handle is in either the UP or DOWN position During a normal cycle landing gear extended and locked can be detected by illumination of the DOWN indicator green light The nose gear squat switch actuated by the nose gear prevents gear retraction whenever the nose gear is compressed by the weight of the aircraft The GEAR UNSAFE red light is on anytime the gear is in transit retracted CA 12 12b 25 MAY 2010 Page 13 of 25 cycle or whenever system pressure drops below 1000 psi with the safety squat switch closed Nose Gear System Description The nose gear consists of a pneudraulic shock assembly mounted in a trunnion assembly a nose gear steering system with bungee a shimmy dampener nose wheel tire and tube hub cap bearings seals and a double ac
21. ting hydraulic actuator for extension and retraction A claw like hook on the actuator serves as a down lock for the nose gear Stop bolts located in the lower aft well prevent inadvertent nose gear collapse Operation The nose gear shock strut is pivoted at the firewall Retraction and extension of the nose gear is accomplished by a double acting hydraulic cylinder the forward edge of which contains the nose gear down lock Initial action of the cylinder disengage the down lock before retraction begins As the strut moves into the gear well the forward side of the nose gear fork boss contacts an actuator assembly causing the doors to close The nose gear is held in the UP position by hydraulic pressure CA 12 12b 25 MAY 2010 Page 14 of 25 MODEL 172RG SERVICE MANUAL NOTE THE LOCKING HOOKS 21 and 24 HAVE BEEN DRY FILM LU BRICATED AT THE FACTORY AND SHOULD LAST THE LIFE OF THE PARTS HOWEVER THEY May be purchased from MAY BE LUBRICATED WITH THE Blectro Film Inc i FOLLOWING PRODUCTS 7116 Laurel Canyon Bivd 1 LUBRI BOND A Hollywood Calif 31605 2 LUBRI BOND 220 x3 PERMASILE X May be purchased from AFTER APPLICATION ALLOW Everlube Corp PARTS TO AIR DRY FOR SIX P O Box 2200 HOURS OR DRY ONE HOUR AT Hi Way 52 N W 120 F West Lafayette Ind 47906 1 Cylinder 10 Lock Pin 18 Bolt 2 Back up Ring 11 Cross Bar 19 Washer 3 Packing 12 Shield 20 Washer 4 Back
22. trical power from the airplane Attach maintenance warning tags to the battery connector and external power receptacle stating WARNING DO NOT CONNECT ELECTRICAL POWER MAINTENANCE IN PROGRESS Support nose wheel so pressure is off the actuator pins Refer to Figure 1 Sheet 1 Detail A Visually inspect actuator pins while physically attempting to rotate and or move actuator pins about all three axes in the bearing end No movement is allowed as pins are a press fit NOTE It is permissible to use locking type needle nose pliers to check for actuator pin looseness movement provided serrated teeth are removed from pliers and no galling marks are transmitted to the actuator pins If any looseness or movement is observed CA 12 12b 25 MAY 2010 Page 20 of 25 1 Install SK210 55 prior to further flight G If looseness or movement is not observed repetitive inspections of the nose gear actuator pins shall be accomplished per the compliance section of this service bulletin 2 Make an entry in the airplane logbook stating compliance with this service bulletin and method of compliance and if applicable when the next inspection is due ILLUSTRATION SHOWS 182RG NOSE GEAR ACTUATOR ATTACHES IN SIMILAR MANNER FOR ALL 172RG AND 210 MODELS NOSE LANDING GEAR INSPECT ACTUATOR PINS FOR LOOSENESS OR MOVEMENT WHILE STILL ON AIRPLANE DETAIL A Figure 1 Down lock Actuator Pin Inspection
23. ulletin Failure to comply with this service bulletin can potentially result in the nose landing gear to not lock in the down position and possibly collapse Compliance is recommended A Initial Inspection Should be accomplished within the next 200 hours of operation or 12 months whichever occurs first CA 12 12b 25 MAY 2010 Page 19 of 25 Repetitive Inspections After completing the initial inspection repeat at each gear retraction check not to exceed 200 hours of operation a After the installation of SK210 155 or later revision the repetitive inspection requirement of this service bulletin is no longer required b After the installation of a replacement actuator bearing end or actuator that was shipped from Cessna Parts Distribution after January 1 1996 the repetitive inspection requirement of this service bulletin is no longer required as these incorporate the modified pin installation Accomplishment Instructions Inspect Nose Landing Ger Actuator Pins Jack the airplane off the ground in accordance with the airplane service manual With Master Switch in the OFF position and the hydraulic pump circuit breaker disengaged select GEAR UP on the gear handle Turn the Master Switch to the ON position and momentarily engage hydraulic pump circuit breaker When gear begins to retract disengage hydraulic pump circuit breaker and place Master Switch to the OFF position Disconnect all elec
24. up Ring 13 Spring 2i Downlock Hook 5 Piston Rod 14 Packing 22 Washer 6 Packing 15 Back up Ring 23 Rod End 7 Knurled Nut 16 Lock Nut 24 Downlock Hook 8 Bearing Head 17 Spring Guide 25 Nut 9 Pin 26 Cotter Pin Figure 5 17 Nose Gear Actuator Downlock Assembly 1 18 2 Similar type of serious incident According to the SACAA accident database a similar type of serious incident occurred at Bloemfontein aerodrome on 28 July 2006 involving a Cessna T210K The pilot CA 12 12b 25 MAY 2010 Page 15 of 25 indicated that he had a landing gear down indication green light in the cockpit but during the landing roll the nose landing gear collapsed The investigation found that one of the nose landing gear down lock pins had failed What made this incident different from the one in question is that Cessna Service Bulletin SEB95 20 was incorporated on this aircraft yet the down lock pin failed in a similar mode 1 19 Useful or effective investigation techniques 1 19 1 None 2 ANALYSIS 2 1 The aircraft was released for service following a detailed maintenance inspection that 2 2 was certified on 30 June 2010 The inspection was conducted in accordance with the aircraft manufacturer s maintenance schedule which required that a detailed inspection be performed on several nose landing gear components The maintenance schedule however does not require that the two down lock pins fitted to the nose landing g
25. wever not possible to draw any comparison between the previous incident dated 18 May 2005 and the one in question due to limited information being available on the previous incident contained to the logbook entry type of maintenance performed CONCLUSION Findings The pilot was the holder of a valid commercial pilot s licence and had the aircraft type endorsed in his logbook The pilot was the holder of a valid aviation medical certificate that was issued by an approved CAA medical examiner The aircraft was maintained in accordance with the approved maintenance schedule and was in possession of a valid certificate of airworthiness at the time of the incident CA 12 12b 25 MAY 2010 Page 17 of 25 3 1 4 The CRMA of the aircraft was valid 3 1 5 The aircraft had flown 7 0 hours since the last maintenance inspection was certified 3 1 6 Cessna Service Bulletin SEB95 20 dated December 29 1995 was not incorporated on this aircraft 3 1 7 The flight was operated as a private flight Part 91 under VFR rules 3 1 8 The was an indistinct landing gear unsafe alarm prior to the nose landing gear collapse which probably could not be heard by the pilot 3 2 Probable cause s 3 2 1 The nose landing gear NLG collapsed following touchdown due to the failure of one of the NLG actuator down lock pins 3 3 Contributory factor s 3 3 1 Cessna Service Bulletin SEB95 20 dated December 29 1995 was not incorporated on th
26. weweEEEEE Licence type Commercial Licence valid Yes Type endorsed Yes Ratings Night rating Medical expiry date 30 September 2010 Restrictions None Previous accidents None Flying experience Total hours 246 2 Total past 90 days Total on type past 90 days CA 12 12b 25 MAY 2010 Page 4 of 25 1 6 Aircraft information 1 6 1 Airframe Type Cessna 172RG Serial no 172RG 0218 Manufacturer Cessna Aircraft Company Year of manufacture 1980 Total airframe hours at time of incident 4 652 10 Last MPI hours amp date 4 645 10 30 June 2010 Hours since last MPI 7 0 C of A issue date 3 September 2004 C of R issue date present owner 2 December 2004 Operating categories Standard Part 135 Engine Type Lycoming O 360 F1A6 Serial no L 27628 36A Hours since new 2 379 40 Hours since overhaul 179 40 Propeller Type McCauley 32D 34C 220B Serial No 000385 Hours since new 1 238 50 Hours since overhaul 998 30 1 6 2 Record of previous major defects and damage sustained Date Airframe hours Brief description of defect 20 04 1982 977 9 Nose gear retracted on take off Firewall forward damaged 11 10 1988 1745 0 Damage to front section cabin floor and l h wing 20 09 1991 2 231 0 Damage to front section nose gear doors cowl flaps 18 05 200

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