section/division occurrence investigation aircraft

CA 12-12a 23 FEBRUARY 2006 of 23

Section/division Occurrence Investigation Form Number: CA 12-12a

AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY

Reference: CA18/2/3/8204

Aircraft Registration ZU-CCY Date of Accident 8 November 2006 Time of Accident 0830Z

Type of Aircraft Sycamore MK I Gyroplane Type of Operation Private

Pilot-in-command Licence Type Gyroplane Pilot Licence Age 39 Licence Valid Yes

Pilot-in-command Flying Experience Total Flying Hours as on 22 October 2006 404.5

Hours on Type as on 22 October 2006

404.5

Last point of departure Rhino Park Aerodrome

Next point of intended landing Private Aerodrome near Machadodorp

Location of the accident site with reference to easily defined geographical points (GPS readings if possible)

In an open field 3 miles from Rhino Park Aerodrome at a geographical position of S 25° 49.826’ E028° 3 3. 072’.

Meteorological Information Surface Wind: 290°/ 5 Knots Temperature: 22°C , Visibility: CAVOK

Number of people on board 1 + 0 No. of people injured 0 No. of people killed 1

Synopsis

At approximately 0830Z on the morning of 8 November 2006, a pilot took off from Rhino Park Aerodrome flying towards Machadodorp when at a height of approximately 500 feet above ground level, the main rotor blades of the gyroplane that the pilot was flying, separated from the motor mast. The cart of the gyroplane immediately fell downwards and impacted with the ground, bursting into flames.

Probable Cause

The main rotor blades separated from the rotor mast in flight, because the bearing sleeve had been assembled upside down. Contributory

A major modification on the aircraft was performed without approval from the appropriate authority after an Authority to Fly had been issued. IARC Date Release Date

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Section/division Occurrence Investigation Form Number: CA 12-12a Telephone number: 011-545-1000 E-mail address of originator: [email protected]

AIRCRAFT ACCIDENT REPORT

Name of Owner/Operator : P R Theron Manufacturer : Chayair Manufacturing Model : Sycamore MK I Nationality : South African Registration Marks : ZU-CCY Place : Rhino Park Date : 8 November 2006 Time : 0830Z All times given in this report is 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 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 given without prejudice to the rights of the CAA, which are reserved.

1. FACTUAL INFORMATION 1.1 History of Flight 1.1.1 On the morning of 8 November 2006 at approximately 0545Z two pilots took off

from a private Aerodrome in Belfast in a Sycamore aircraft on a flight to Rhino Park Aerodrome, in order to collect another Sycamore aircraft on behalf of the owner.

1.1.2 After flying for approximately one hour, they landed at Witbank Aerodrome in order

to uplift fuel for the flight to Rhino Park Aerodrome. 1.1.3 They departed from Witbank at approximately 0700Z and landed at Rhino Park

Aerodrome at approximately 0730Z. 1.1.4 The pilot of ZU-CCY repositioned the aircraft outside the hanger and performed a

pre-flight inspection. He then requested the pilot who had accompanied him to Rhino Park, to take off first and circle wide.

1.1.5 After taking off at approximately 0830Z from Rhino Park Aerodrome towards

Machadodorp and flying away in formation next to each other at a height of approximately 500 feet above ground level, the main rotor blades separated from the gyroplane. The cart of the gyroplane immediately fell downwards and impacted with the ground, before bursting into flames.


1.2 Injuries to Persons

Injuries Pilot Crew Pass. Other Fatal 1 - - - Serious - - - - Minor - - - - None - - - -

1.3 Damage to Aircraft 1.1.3 The aircraft was destroyed by a post-impact fire.

Figure1: Indicating the damages that the aircraft had sustained. 1.4 Other Damage 1.4.1 A grass area around the wreckage and within a diameter of approximately 22

metres was burnt following the accident.

Figure 2: Indicating the area of grass which was burnt.


1.5 Personnel Information 1.5.1

Nationality South African Gender Male Age 39 Licence Number ########## Licence Type Gyroplane Pilot Licence valid Yes Type Endorsed Yes Ratings Gyroplane Instructor Medical Expiry Date 03 March 2010 Restrictions None

Previous Accidents

On 12 October 2003, in a gyroplane wherein the pilot experienced a sudden change in wind direction, resulting in loss of transitional lift and followed by a very hard landing.

Flying Experience:

Total Hours 653.7 Total Past 90 Days 37.2 Total on Type Past 90 Days 37.2 Total on Type 404.5

1.5.2 The pilot had obtained a helicopter student pilot’s licence on 14 January 1998. On

18 May 1998, the pilot obtained a helicopter private pilot’s licence after 63.5 flying hours. According to available documentation, the pilot’s helicopter licence expired on 28 August 2003. The last recorded flying hours on record on helicopters, which was on 11 October 1999, was 200.3 hours.

1.5.3 Following his application, the pilot was issued with a student microlight pilot’s licence on 8 February 2001. The pilot obtained a microlight pilot’s licence on 31 May 2001 after 29.6 flying hours. The microlight pilot’s licence expired on 30 May 2003. Information obtained from the pilots file at the Civil Aviation Authority indicated that the pilot’s total flying hours and experience on microlight aeroplanes was 48.9 flying hours.

1.5.4 On 21 November 2002, the pilot applied for, and was issued with a student gyroplane licence. On 28 February 2003, the pilot applied for, and was issued with a gyroplane licence after 26.6 flying hours. The pilot thereafter obtained a gyroplane instructor’s rating on 30 March 2006 after a total of 220.7 flying hours on gyroplanes.

1.6 Aircraft Information

Airframe: Type Sycamore MK I Serial Number Syca 0010 Manufacturer Chayair Manufacturing Year of Manufacture 2000 Total Airframe Hours (At time of Accident) Unknown Last Annual Inspection (Date & Hours) 141.35 17 June 2006 Hours since Last Annual Inspection Unknown Authority to Fly (Issue Date) 28 June 2006 C of R (Issue Date) (Present owner) 22 March 2003


Operating Categories Private

Engine: Type Rotax 914 Serial Number 4417907 Last recorded hours since New 206.55 Last recorded hours since Maintenance 17.20

Propeller: Type Arplast 68” 3 blades Serial Number None Last recorded hours since New Unknown Hours since Overhaul Not Applicable

Rotor blades: Type Rotor Hawk blades Serial Number None Last recorded hours since New Unknown Hours since Overhaul Not Applicable

Note: This gyroplane was involved in an accident on 4 August 2001. The pilot, who was the owner of the aircraft, lost control of the aircraft during take-off due to wind shear. The aircraft sustained damage to the airframe, landing gear, rotor blades and propeller.

1.7 Meteorological Information 1.17.1 The following official weather information was obtained from the South African

Weather Services of 8 November 2006:

Wind direction 290° Wind speed 5 Knots Visibility Clear Temperature 22°C Cloud cover None Cloud base None Dew point 10°C

Surface Analysis A high pressure system was south-east of the country, extending into the eastern part of the country with a trough of low pressure over the western part of the country. The weather was fine over Gauteng and the western part of the Mpumalanga Province.

Upper air Analysis

At 500hpa, a high pressure was present over the country. 1.8 Aids to Navigation 1.8.1 The aircraft was equipped with a Gamin III GPS, which was destroyed in the fire.

No recorded or reported defects were experienced with the navigation equipment.


1.9 Communications 1.9.1 The aircraft was equipped with a Microair 760 panel-mounted radio. There were no

recorded defects experienced with the communication equipment. 1.9.2 Rhino Park aerodrome is an unlicensed and unmanned aerodrome. The pilot of ZU-

CCY was transmitting his intentions on VHF Frequency 135.6 MHz and after take- off he changed to VHF Frequency 124.8.

1.9.3 Pilots who were flying in the circuit of Rhino Park Aerodrome at the time when the

accident aircraft got airborne stated that the pilot of ZU-CCY had broadcasted to the other pilot who was to fly with him in another gyroplane, “Fly on my right-hand side” and that no further communications were then heard from the pilot.

1.10 Aerodrome Information

1.10.1 The pilot took off from Rhino Park Aerodrome.

Aerodrome Location Rhino Park Aerodrome Aerodrome Co-ordinates S25° 50’57.0 E028° 32’30.0 Aerodrome Elevation 4780 Feet Runway Designations 09/27 01/19 Runway Dimensions 850 x 20 Meter 400 x 20 Meter Runway Used 27 Runway Surface Sand Approach Facilities None

1.10.2 The accident occurred on an open grass area at the geographical position: S25°

49.825’ E028° 33.072’. 1.11 Flight Recorders 1.11.1 The gyroplane 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 gyroplane.

1.12 Wreckage and Impact Information 1.12.1 Moments after take-off from Runway 27 at an altitude of approximately 500ft Above

Ground Level (AGL), the main rotor blades of the gyrocopter separated from the rotor mast. The gyroplane then impacted with the ground and on impact with the ground, a fire erupted.

1.12.2 The gyroplane impacted with the ground on an open grass field area approximately

3 miles from Runway 27 at Rhino Park Aerodrome at a geographical position of S 25° 49.826’ E028° 33. 072’.The main rotor blades we re found 42.7 metres from the main wreckage.

1.12.3 The distance from the first impact marks where the nose wheel impacted with the

ground, to where the wreckage came to rest, was approximately 19.5 metres, on a


direction 120 degrees magnetic.

Figure 3: Indicating the distance from the first impact marks until the wreckage came to rest.

Figure 4: Indicating the distance between the main rotor blade and the wreckage. 1.13 Medical and Pathological Information 1.13.1 A post-mortem examination was performed on the deceased pilot after the accident.


1.13.2 The results of the post-mortem report and toxicology tests were not available at the time when the report was compiled. Should any of the results be available, an attachment will be added to this report to include the results.

1.14 Fire 1.14.1 A post-impact fire erupted when the aircraft impacted with the ground. The aircraft

was destroyed by the post-impact fire. 1.14.2 The aircraft caught fire on impact with the ground, most probably due to the fuel

tank which raptured as a result of impact with the ground, thus causing fuel to leak on the hot engine, which in turn ignited the fuel.

1.15 Survival Aspects 1.15.1 The accident was not considered survivable, due to the magnitude of the impact

forces and the severity of the post-impact fire which erupted moments after impact. 1.16 Tests and Research 1.16.1 Following the accident, the engine was dismantled by an approved Rotax engine

agent to determine if the engine operated properly prior to impact, and that it did not contribute to the accident.

The report into the investigation on the engine concluded as follows:

Findings

The aircraft was severely burnt during the fire. The important point was to attempt to determine whether the engine was running during the flight or could have been the cause of the accident. The engine was partly disassembled and no apparent seizures were found. The gearbox was inspected and no failure was found that could have led to an engine failure. The propeller was inspected; two blades were burnt but the third was recovered a distance from the wreck. By the damage on this blade it appears that the engine was turning on impact and that the blade had struck something eg. the lower keel and then was torn from the hub. All propeller bolts and gearbox studs were bent. This also indicated an engine running on impact. No sign of the execution of a forced landing was found.

1. Analysis

The engine was burnt. It was thus impossible to place the engine on a test stand to determine the status of the engine. By methodically working through the components, switches and engine parts still available it was found that the switches appeared in the correct position for flight. The engine components were badly damaged from the fire, but there were no apparent seizures that could point to an engine failure before impact. The gearbox was intact and the major components in the engine were also intact.

2. Conclusion It would seem that the engine had been running at the point of impact. 1.16.2 On 24 May 2006, the unregistered owner of the aircraft made an application for the


approval of a modification of new rotor blades and a hub bar to the SACAA. On 5 July 2006, a Proving Flight Authority was issued in the name of the unregistered owner by the SACAA in order to test the new rotor blades and hub bar as per the modification approval. Following the modification approval, on 28 June 2006 a Private Authority to Fly was issued with an expiry date of 17 June 2007. The modification approval issued by the SACAA entailed that:

• A CRMA had to be completed, • The owner/operator had to ensure that the equipment list was updated to

reflect the change, • The Certificate of Airworthiness or the Permit to Fly issued to the aircraft

would become invalid if all the conditions as stated above are not met, • An appropriately rated AMO/AP to certify the installation/repair/ modification, • Form CA43-17 Mass and Balance Data to be completed in duplicate, for all

applications, and submitted to the SACAA, • Proof of flight hours with new rotors (10 Hours), • Had to submit CA103-02 for aircraft climb performance.

1.16.3 During the investigation into the aircraft accident, it was established that in July

2006 the unregistered owner of the aircraft had requested a design company to design and manufacture a rotor head intended for a sycamore gyroplane. The reason for the new rotor head was to reduce stick shake which was experienced on the aircraft.

1.16.4 After receiving the newly manufactured rotor head, the unregistered owner stated

that he had transferred all the working parts from the old rotor head to the new rotor head. It was further stated by the unregistered owner that the aircraft had performed well after the new rotor head had been fitted and that no stick shake was thereafter experienced.

Part 24.01.2 of the Civil Aviation Regulations (CAR) of 1997 pertaining to Airworthiness states:

(1) Before a non-type certificated aircraft, other than an aircraft classified in sub-groups (h) to (l) in sub-regulation 24.01.1(2), is considered to be airworthy it shall–

(a) have been issued with –

(i) an Authority to Fly or a Proving Flight Authority, as the case may be, in terms of this Part; and

(ii) a valid certificate of Release to Service;

(b) have been maintained in accordance with the provisions of this Part and of Part 43, as applicable to the type of aircraft; and

(c) have no known condition which could make the aircraft unsafe for flight.

Part 24.01.5 of the Civil Aviation Regulations (CAR) of 1997 pertaining to Maintenance and inspection states:

(1) The owner of a non-type certificated aircraft for which an Authority to Fly is required in terms of these regulations shall –


(a) submit to the Commissioner or, if applicable: to the organisation designated for the purpose in terms of Part 149 of these Regulations, as the case may be, for approval an Approved Maintenance Schedule or similar document for the aircraft;

(b) ensure that the non-type certificated aircraft is maintained in compliance with –

(i) its Approved Maintenance Schedule or similar document; and

(ii) to the extent applicable, the requirements of Part 43.

Part 43.02.12 of the Civil Aviation Regulations (CAR) of 1997 pertaining to modifications states:

(1) No person shall, without the prior written approval of the Commissioner, carry out any modifications, including changes to equipment or the installation thereof, which affect, or are likely to affect, the serviceability of the aircraft, or the safety of its occupants or of any other persons or property.

(2) Before the approval of the Commissioner is considered for a modification as referred to in sub-regulation (1), the owner of the aircraft, or any other person who applies for the modification, shall -

(a) Furnish the Commissioner with such information, data, calculations, reports on tests, drawings or wiring diagrams relating to the design, and proof of effectiveness or airworthiness of such modification, as the Commissioner may require; and

(b) be accompanied by the appropriate fee as prescribed in Part 187.

(3) Notwithstanding the provisions of sub-regulations (1) and (2), such modifications as may from time to time be recommended by the manufacturer of the type of aircraft or equipment concerned, may be carried out if the modifications are carried out in accordance with the said manufacturer's recommendations.

During the investigation into the accident, no evidence was found that entries were made in the aircraft logbook of the new modification which was done on the aircraft. No evidence was found that an application was made/submitted to the Civil Aviation Authority for an approval of the modification for the newly designed rotor head.


Figure 5: Original Sycamore rotor head design 1.16.5 Evidence found showed that after the new rotor head was fitted to the aircraft, the

aircraft was flown for 1.3 hours by the unregistered owner on 28 July 2006.


1.16.6 On 25 October 2006 the aircraft was flown from Fly Inn Aerodrome where the aircraft was based, to Rhino Park Aerodrome, by the unregistered owner. The flight was 30 minutes. The reason why the aircraft was flown to Rhino Park was that an Approved Person had to perform some work on the aircraft before it was to be sold to another person yet again.

1.16.7 The Approved Person stated that he had performed the following work on the

aircraft:

• Moved the throttle control back to original position. (To the left-hand side of the aircraft.)

• Turned pre-rotator lever on joystick for Right-Hand control. • General check-over.

Following the general check-over, the Approved Person stated in writing that he had carried out the following work on the aircraft: “While checking rotor teeter angles, the four ring gear bolts were found to be cut on the bolt head, in order to allow the rotor to reach full teeter, by moving past the cut head to reach the teeter stops. These four bolts were replaced by M8 Allen Cap bolts. The only way to avoid the rotor from making contact with these four bolts was to countersink the holes. One bolt was removed to check bolt length with replacement bolts. In order to countersink the holes, the rotor had to be removed. The rotor was removed by chain block, suspending it above the rotor head so that the head could be turned 360. The rotor head was locked in place by locking the joystick and clamping the rotor brake. One by one the bolts were replaced. Rotor was lowered back into the towers, copper-slip was applied to the teeter bolt and teeter bolt was secured and checked for rotation on teeter. Pre-rotator was checked for correct contact with ring gear. No other work was done on this aircraft”.

1.16.8 Differences were found during the investigation, between the rotor head assembly

on the accident aircraft and the originally designed sycamore manufactory rotor head assembly.

Accident aircraft rotor head

Sycamore original rotor head


Figure 6: Indicating the differences between the two rotor heads.

Diagram of the Sycamore Rotor System Assembly


It was found that there were no serial numbers on the newly designed tower and no evidence was found that diagrams of the newly designed tower were submitted to the Civil Aviation Authority for approval. It was found that the unregistered owner, who is an Approved Person, was not in possession of, and did not use the maintenance manual or a parts catalogue of the Sycamore type aircraft when he worked on the aircraft. It was established during the investigation that it was not possible for the main rotor bolt, washer and bearing sleeve to fit into the newly designed rotor head, as it would not have left enough clearances for the rotor hub to tilt. It was found that the teeter plate on the new tower head was removed, the newly designed head machined at the bearing block and that the four ring gear bolts heads were cut to enable the hub bar to teeter not less than 6 degrees. It was found that the main rotor bolt which attaches the rotor head to the universal block was fitted the wrong way around into the rotor head. It was found that the main rotor bolt head was machined off.

Figure 7: Indicating the main rotor bolt machined off.

Original main rotor bolt

The machined main rotor bolt found on the accident aircraft.


It was found that the washer which is normally fitted between the bolt head and the bearing sleeve was missing. It was found that the spacer was also machined smaller.

Figure 8: Indicating that the spacer fitted to the accident aircraft was smaller than the original spacer used on the Sycamore aircraft type.

Main rotor bolt assembly on the accident aircraft.

Main rotor bolt assembly on a sycamore aircraft which was fitted in the factory.

Bolt head machined off.

Washer missing.

Bearing sleeve assembled the wrong way around.

Spacer which was fitted to the accident aircraft.

The original spacer.


Figure 9: Indicating the differences between the 2 main rotor bolt assemblies.

Figure 10: Indicating the new rotor system design.

1.16.9 The design and manufacturing company who designed and manufactured

the new rotor head which was found on the accident aircraft was contacted.

The company made the following statements in writing: “Preview


The owner approached me during July 2006 to design and manufacture a rotor head intended for a Sycamore gyro plane. The reason for the new rotor head was to fit a new rotor to the gyro plane and the owner needed the teeter point of the rotor to be 20mm lower than the original Rotor head of the Sycamore. Disassembly of Existing Tower

• The existing tower that was on the Gyro plane was given to me by the owner.

• The owner said to me that he wants to use the two bearings, bush, bolt, washers, spacers and nut of the existing tower in the new tower.

• I disassembled the existing tower taking out the two bearings and bush assembly out of the existing tower. The bearings were not removed from the bush.

• I then did all the necessary measurements to design the new tower. Assembly and delivery of the new Rotor Tower

• I did not do the assembly of the new rotor tower. • The manufactured new tower and the existing rotor tower were given

to the owner. • The following components were delivered

1. 16202 Rotor Tower; Sycamore Mod 2. 16204 Plate Tower; Bottom 3. 16205 Sycamore Teeter plate 4. 15868 5/16” AN365-524 Fibre lock Nuts 5. 15867 5/16” AN5-30 A Bolt; ZNB

• The new manufactured tower was delivered without any modifications done to the component.

Interview with CAA � The CAA investigators showed me what looked like the AN bolts I

supplied. Their heads have been ground smaller on one side. � The rotor head were chamfered on both sides. � The holes for the AN bolts were counter sunk to accept grade 8.8 cap

screws which were instead of the AN bolts. � The teeter stop plate (part Number 16205) was not present. � The bearings were in the assembly. � The CAA investigators showed me a main bolt from another aircraft

and asked me if the bolt I received from the owner were similar. They also informed me that the bolt retrieved from the accident’s head was machined thinner. As far as I can remember the bolt received from the owner looked liked the bolt they showed me without any machining.

1.16.10 Part 43.04.7 of the Civil Aviation Regulations (CAR) of 1997 pertaining to

duplicate inspection of controls states:

(1) No person shall certify an aircraft component for release to service after the initial assembly, subsequent disturbance or adjustment of any part of an aircraft or component control


system unless - (a) a duplicate safety inspection of the control system has

been carried out; and (b) the duplicate safety inspection is recorded and certified

in the appropriate logbook, or other maintenance record approved by the Commissioner.

(2) A duplicate safety inspection authorised in terms of sub-

regulation (1), shall consist of- (a) an inspection by a person referred to in Regulation

43.04.1 to certify the release to service of the control system after maintenance; and

(b) a second inspection carried out by another person who is a person referred to in Regulation 43.04.1

No evidence was found that a second inspection was carried out by another person after the unregistered owner transferred all the working parts from the old rotor head to the new rotor head.

1.16.11 The manufacturer of the Sycamore aircraft type was consulted during the

investigation. The manufacturer made the following remarks in writing:

“1. The rotor head was another make and not supplied nor approved by the Manufacturer.

2. There were critical design flaws in this head, and this caused the separation of the rotor head.

3. In original form the bearings with the bearing sleeve, a washer and main rotor bolt, is assembled from the top into the bearing block. The stop plate and teeter towers is then attached to this assembly, and is then fixed to the ring gear and bolted to the torque tube with the spacer in place, by means of the main rotor bolt.

4. The head that I saw had the teeter towers and bearing block machined as a single piece of material with the design in a way that the bearings is assembled from the bottom. They also assembled the bearing sleeve from the bottom. A main rotor bolt was fitted from the top, but the head was machined lower and most importantly without a washer and (as previously mentioned) with the bearing sleeve fitted from the bottom.

5. We then took measurements to see if the rotor head could be assembled in a way that resembles the way that reflects the original design. We could do this, but because of the bearing sleeve being the other way around with its shoulder on top and the washer the main rotor bolt lifted 6mm. This would mean that the rotor would not fit in the space left between the teeter bolt and the top of the main rotor bolt.”

1.17 Organisational and Management Information 1.17.1 This was a private flight. The pilot was not the owner of the aircraft. 1.17.2 The Approved Person who performed the annual inspection prior to the accident

was in possession of a MISASA accredited approval.


1.18 Additional Information 1.18.1 Part 47.00.7 of the Civil Aviation Regulations (CAR) of 1997, pertaining to the duties

of the holder of a certificate.

The holder of a certificate of registration shall –

(a) keep the original certificate of registration in a safe place and produce such certificate to an authorised officer, inspector or authorised person for inspection if so requested by such officer, inspector or person;

(b) carry a certified true copy of the certificate of registration in the aircraft at all times;

(c) notify the Commissioner in writing if the particulars of the person referred to in Regulation 47.00.5(2)(a)(v)(bb), (vi)(bb), (vii)(bb) or (viii)(bb), as the case may be, are changed.

Point 5 on the Authority to Fly certificate states that:

“This authority is rendered invalid if the ownership of the aircraft is changed and must be returned to the Commissioner within 30 days.”

According to available records and evidence the aircraft was sold, and the aircraft changed ownership on 11 February 2003, but no change of ownership documentation was ever submitted to the Civil Aviation Authority. Available evidence shows that the aircraft is still registered in the name of the first owner since 22 March 2000.

1.19 Useful or Effective Investigation Techniques 1.19.1 None. 2. ANALYSIS 2.1 After take-off and approximately 3 nautical miles from Rhino Park Aerodrome and at

an altitude of approximately 500 feet above ground level, the main rotor blades separated from the gyroplane aircraft. The rest of the aircraft then impacted with the ground and caught fire.

2.2 The accident occurred in daylight. Fine weather conditions prevailed at the time and

place of the accident and the weather therefore was considered not to have contributed to the accident.

2.3 Although the aircraft was in possession of a valid Authority to Fly at the time of the

accident, and it did not contribute directly to the accident, it was found during the investigation that the Authority to Fly and the certificate of registration were not registered in the name of the owner. The unregistered owner stated that he had bought the aircraft on 11 February 2003 from the owner as stated on the aircraft documents.

2.3.1 Further to the above, although the aircraft had a valid Authority to Fly, the change of


the rotor head can be considered as a major modification, and therefore it could be considered that this had an impact on the validity of the Authority to Fly.

2.4 The pilot was medically fit and was in possession of a valid licence with an expiry

date of 15 March 2007. The aircraft type was endorsed in the pilot’s licence at the time of the accident.

2.5 The pilot was not the owner of the aircraft. The pilot intended to fly the aircraft on

behalf of the new owner from Rhino Park to Machadodorp in Mpumulanga. 2.6 During the investigation it was found that on 24 May 2006 an application for

approval of a modification of new rotor blades and hub bar was made to the Civil Aviation Authority. On 5 July 2006 a Proving Flight Authority was issued in the name of the unregistered owner in order to test the new rotor blades and hub bar as per the modification approval. Following the modification approval, on 28 June 2006 a Private Authority to Fly was issued with an expiry date of 17 June 2007.

2.6.1 In July 2006, a request was made to a design company to design and manufacture

a rotor head intended for a sycamore gyroplane. The reason for the new rotor head was to reduce stick shake (vibration) which was experienced on the accident aircraft. No modification approval request was made to the Civil Aviation Authority for the new modification on the rotor head.

2.6.2 It is believed that the process and legal requirements for modifications and

inspections were known to the unregistered owner who was the Approved Person who requested the new rotor head, and especially when a rotor head is regarded as a critical component as per the Civil Aviation Regulations.

2.7 During the investigation into the accident the following were found: 2.7.1 The new tower head which was manufactured and fitted to the aircraft occurred

without a dual inspection having been performed, and this is regarded as a safety deficiency.

2.7.2 No maintenance manual and parts catalogue were used during the assembling process of parts on the aircraft and this is regarded as a safety deficiency.

2.7.3 The main rotor bolt was machined, most probably to allow for enough clearance to assist the hub bar to teeter.

2.7.4 The spacer which is used between the rotor gear and the bearing was found to be machined and smaller in size than the original spacer used in the assembling process of an original Sycamore aircraft type rotor head; most probably to fit into the new tower to allow clearance for the hub bar to teeter.

2.7.5 The washer between the main rotor bolt and bearing sleeve was not found on the accident aircraft in the position it was supposed to be in, most probably to allow for more clearance for the hub bar to teeter.

2.7.6 Examination of the design drawings of the newly manufactured rotor head revealed that the teetering plate included in the drawing was not found on the accident aircraft rotor head. The teetering plate most probably did not allow for the correct teetering to take place.

2.7.7 Examination of the rotor head on the accident aircraft and the design drawings revealed that the rotor head had chamfers on both sides of the rotor most probably to assist with teetering, and probably to get the desired teetering.

2.7.8 Four ring gear bolts heads were found cut and were found removed and replaced by M8 Allen Cap bolts. In order to prevent the rotor blade hub bar from making contact with the four bolts, the holes were counter-sinked.


2.8 It was reported that the pilot did perform a pre-flight inspection of the aircraft prior to take-off. It was further found during the investigation that it would not have been possible for the pilot to have seen the components which failed and which led to the accident, as this does not form part of the pre-flight inspection. Therefore the bearing sleeve which was assembled upside down in the tower would not have been visible to the pilot.

2.9 The Approved Person who performed work on the aircraft on behalf of the un-

registered owner and who was responsible for the replacement of the AN5-30A Bolts with M8 Allen Cap bolts, stated that in the process that he followed to replace these bolts it was not required of him to remove the rotor head from the rotor gear and airframe and therefore the bearing sleeve which was assembled upside down in the tower would not have been visible to him, either.

2.10 The unregistered owner who was responsible for the manufacturing and installation

of the new rotor head stated that he had transferred all the working parts from the old tower to the new tower.

2.11 It was, however, confirmed by the manufacturer of the original rotor head from

Sycamore that the tower could only have been assembled in a certain way. 3. CONCLUSION 3.1 Findings 3.1.1 No evidence was found that the Approved Person, who was also the unregistered

owner, had requested a Modification Approval for the changing of the rotor tower. 3.1.2 No evidence was found that the Approved Person/non-registered owner had used a

maintenance manual when he assembled and disassembled the aircraft hub’s blades and tower.

3.1.3 No evidence was found that the AP/ unregistered owner had entered the hours of

the aircraft in the aircraft’s logbook. 3.1.4 The AP/ unregistered owner flew the aircraft from Fly Inn Aerodrome to Rhino Park

Aerodrome on 27 October 2006. The flight was about 30 minutes. 3.1.6 The Approved Person/ unregistered owner did not enter the new modification,

which was indicated in the aircraft’s logbook. 3.1.7 The new tower head which was manufactured and fitted to the aircraft occurred

without a dual inspection having been performed, which is regarded as a safety deficiency.

3.1.8 No maintenance manual and parts catalogue were used during the assembling

process of parts on the aircraft and this is regarded as a safety deficiency. 3.1.9 The main rotor bolt was machined, most probably to allow for enough clearance to

assist the hub bar to teeter. 3.1.10 The spacer which was used between the rotor gear and the bearing was found to

be machined and smaller in size than the original spacer used in the assembling process of an original Sycamore aircraft type rotor head; most probably to fit into


the new tower to allow clearance for the hub bar to teeter. 3.1.11 The washer between the main rotor bolt and bearing sleeve was not found on the

accident aircraft in the position it was supposed to be, but most probably to allow for more clearance for the hub bar to teeter.

3.1.12 The teetering plate included in the drawings of the newly designed rotor head was

not found on the accident aircraft’s rotor head. 3.1.13 The teetering plate was removed from the rotor head, as it did not allow for the

correct teetering to take place. 3.1.14 Chamfers on both sides of the newly designed rotor head were found to assist with

teetering. 3.1.15 Four ring gear bolts heads were found cut. These were removed by the Approved

Person who had last worked on the aircraft and replaced by M8 Allen Cap bolts. 3.1.16 A Proving Flight Authority was issued in the name of the unregistered owner by the

SACAA. 3.2 Probable Cause/s 3.2.1 The main rotor blades separated from the rotor mast in flight, because the bearing

sleeve had been assembled upside down.

Contributory

3.2.2 A major modification on the aircraft was performed after an Authority to Fly had been issued, without approval from the appropriate authority.

4. SAFETY RECOMMENDATIONS 4.1 It is recommended that modifications to critical components on the aircraft be done

by the manufacturer of the aircraft type. 4.2 It is recommended that serial numbers be attached to components used on none

type certified aircraft. 4.3 It is recommended that the CAA introduce measures to ensure that Proving

Authorities to Fly and Authorities to Fly are issued to registered owners and not to unregistered owners.


5. APPENDICES 5.1 None.

-END-

Report reviewed and amended by Advisory Safety Panel 26 May 2009.

section/division occurrence investigation aircraft

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