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Section/division Occurrence Investigation Form Number: CA
12-12b
AIRCRAFT INCIDENT REPORT AND EXECUTIVE SUMMARY
Reference: CA18/3/2/0849
Aircraft Registration ZS-OTF
Date of Incident 15 June 2011 Time of Incident 0800Z
Type of Aircraft Boeing 737-436 Aircraft Type of Operation
Scheduled Domestic Flight
Pilot-in-command Licence Type Airline Transport Age 62
Licence Valid Yes
Pilot-in-command Flying Experience
Total Flying Hours
PIC: 21780.0 1st Officer: 2218.0
Hours on Type
PIC: 6800.0 1st Officer: 170.9
Last point of departure O.R Tambo International Aerodrome (FAJS)
Gauteng Province
Next point of intended landing Cape Town International Aerodrome
(FACT) Western Cape Province
Location of the Incident site with reference to easily defined
geographical points (GPS readings if possible)
O.R Tambo International Aerodrome (FAJS) Gauteng Province at GPS
position S26° 08.02’ E028° 14.34’
Meteorological Information
Fine weather conditions prevailed at the time of the incident.
The wind was calm at
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Section/division Occurrence Investigation Form Number: CA
12-12a
AIRCRAFT INCIDENT REPORT
Name of Owner/Operator : Lexshell 779 Investments (Pty) Ltd /
Comair (Pty) Ltd Manufacturer : Boeing Aircraft Company Model :
737-436 Nationality : South African Registration Marks : ZS-OTF
Place : O.R Tambo International Aerodrome (FAJS)
Gauteng Province Date : 15 June 2011 Time : 0800Z 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 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 Incidents 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 15 June
2011 at approximately 1000Z, during daytime conditions, flight
BA413
(ZS-OTF) took-off from Rwy 03L at O.R Tambo International
Aerodrome on a scheduled domestic flight to Cape Town International
Aerodrome.
1.1.2 During the take-off run, the number 1 tire tread separated
and caused minor damage to the aircraft.
1.1.3 After the take-off, debris, including tire tread and a
wheel-well slave door, were found on the runway at O.R Tambo. The
captain was advised about the thread separation but elected to
continue with the flight. The Aerodrome Rescue and Fire Fighters at
Cape Town International Aerodrome was alerted.
1.1.4 The remainder of the flight to Cape Town was uneventful
and the landing did not result in any emergency.
1.1.5 After disembarking the passengers, an inspection revealed
damage to the flap(s) in the direct vicinity of the #1 wheel and
tire as well as to the left hand landing gear doors.
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1.2 Injuries to Persons
Injuries Pilot Crew Pass. Other Fatal - - - - Serious - - - -
Minor - - - - None 2 4 81 0
1.3 Damage to Aircraft 1.3.1 The aircraft sustained minor to
substantial damage to the left hand flaps and the
outer centre and lower slave doors. The inner slave door was
missing and most of the rod ends in that area sustained damage
during the incident.
1.4 Other Damage 1.4.1 There was no other damage to any
buildings, vehicles, navigation facilities,
aerodrome structures and installations or any damage to the
environment. 1.5 Personnel Information
Captain:
Nationality South African
Gender Male Age 62
Licence Number 0270088701 Licence Type Airline Transport Licence
valid Yes Type Endorsed Yes Ratings Instrument Medical Expiry Date
31 October 2011
Restrictions Corrective lenses Annual Urulogist’s report
Previous Incidents None Flying Experience:
Total Hours 21780 Total Past 90 Days 76.5 Total on Type Past 90
Days 76.5 Total on Type 6800
1st Officer / Co-pilot
Nationality South African Gender Male Age 38
Licence Number 0272297151 Licence Type Airline Transport Licence
valid Yes Type Endorsed Yes Ratings Instrument Medical Expiry Date
31 October 2011 Restrictions Corrective lenses Previous Incidents
Nil
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Flying Experience:
Total Hours 2218 Total Past 90 Days 74.3 Total on Type Past 90
Days 74.3 Total on Type 170.9
1.6 Aircraft Information
Airframe : Type Boeing 737-436 Serial Number 25305 Manufacturer
Boeing Aircraft Company Date of Manufacture 1991 Total Airframe
Hours / Cycles (At time of Incident)
42461.59 / 30671.0
Last C-check (Date & Hours) 12 June 2011 42442.25 Hours
since Last C-check 19.34 C of A (Issue Date) 18 January 2002 C of R
(Issue Date) (Present owner) 11 January 2002 Operating Categories
Standard
Engine 1: Type CFM56-3C1 Serial Number 723158 Hours since New
65435 Cycles since New 52522 Hours / cycles since last C-check
65354 / 52460
Hours / cycles since O/H N/A – Engine on condition Engine 2:
Type CFM56-3C1 Serial Number 856380 Hours since New 41483 Cycles
since New 27993 Hours / cycles since last C-check 41402 / 27931
Hours since O/H N/A – Engine on condition
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Tire #1 Record: (See Appendix A” for Tire Manufacturer
Report)
Make & Description
Dunlop Bridgestone H40x14.5 – 19 / 26PR*225MPH
Pattern F2D Part Number APS01337 BS Serial Number 608NH092 Hours
/ cycles since New 8812 / 6335 Hours / cycles since O/H 257 / 45
TBO cycles 1800
1.7 Meteorological Information
Wind direction Calm Wind speed
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1.10 Aerodrome Information
Departure Aerodrome:
Aerodrome Location O.R Tambo International Airport
Aerodrome Co-ordinates S26° 08.02’ E028° 14.34’ Aerodrome
Elevation 5558 ft ASL Runway Designations 03R/21L 03L/21R Runway
Dimensions 3400m x 60m 4418m x 60m Runway Used 03L Runway Surface
Tarred Approach Facilities Not applicable
After the take-off, debris, including tire tread and a
wheel-well slave door, were found on the runway.
Destination Aerodrome:
Aerodrome Location Cape Town International Airport
Aerodrome Co-ordinates S33° 58.05’ E018° 36.19’ Aerodrome
Elevation 151 ft ASL Runway Designations 01/19 Runway Dimensions
3201m x 60m Runway Used 01 Runway Surface Tarred Approach
Facilities Not applicable
1.11 Flight Recorders 1.11.1 The aircraft was equipped with a
flight data recorder and a cockpit voice recorder.
Neither recorder was downloaded following the incident. 1.12
Wreckage and Impact Information 1.12.1 Minor damage was sustained
by the upper and mid flap lower surfaces and
substantial damage to the lower flap.
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Figure 1: Damage to the upper and mid flap lower surfaces and
the lower flap.
Figure 2:Damage to the lower surface of the lower flap.
1.12.2 The outer centre and lower slave doors also sustained
minor damage. The inner
slave door was missing and most of the rod ends in that area
sustained damage.
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Figure 3: Damage to the lower Landing gear door.
Figure 4: Damage to the number 1 tire.
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1.13 Medical and Pathological Information 1.13.1 Not applicable.
1.14 Fire 1.14.1 There was no evidence of fire in flight or after
the impact. 1.15 Survival Aspects 1.15.1 Not applicable. 1.16 Tests
and Research 1.16.1 The tire in was dispatched to the manufacturer
for further examination as to the
cause of the thread separation. 1.16.2 According to the
manufacturer there was sufficient evidence to conclude that
there
was a mechanical breakdown of adhesion within the 5 ply casing
repair plug between the repair rubber and casing cord structure.
Examination showed that the break down has developed over a small
number of landings.
1.16.3 It is clearly evident that during the last take-off the
break down was exacerbated
due to the weight of the unworn thread which was sufficient to
pull away from the casing due to significant centrifugal forces
imparted during take-off at a high airport and at the maximum
aircraft loading and take-off speed.
1.16.4 The tire was found to be completely satisfactory on
shearography inspection and
the tire was retreaded and final inspected in accordance with
approved retread procedures and specifications.
1.17 Organizational and Management Information 1.17.1 The
operator was in possession of a valid AOC. 1.17.2 According to
available documentation, the aircraft was maintained as required
by
the manufacturer and the Regulator and the maintenance
organization was in possession of a valid maintenance
certificate.
1.18 Additional Information 1.18.1 Not applicable. 1.19 Useful
or Effective Investigation Techniques 1.19.1 Not applicable.
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2. ANALYSIS 2.1 The aircraft took off from O.R Tambo
International Aerodrome on a scheduled
domestic flight to Cape Town International Aerodrome. During the
take-off run, the number 1 tire tread separated. After the
take-off, debris, including tire tread and a wheel-well slave door,
were found on the runway at O.R Tambo. The captain was advised
about the thread separation but elected to continue with the
flight. The Aerodrome Rescue and Fire Fighters at Cape Town
International Aerodrome was alerted, however, the remainder of the
flight to Cape Town was uneventful and the landing did not result
in any emergency. After disembarking the passengers, an inspection
revealed damage to the flap(s) in the direct vicinity of the #1
wheel and tire as well as to the left hand landing gear doors. It
is evident that the operator operates under severe operating
conditions and it is considered possible that the maximum
performance of the aircraft may have been beyond the capability of
this approved repair process.
3. CONCLUSION 3.1 Findings 3.1.1 The flight crew were licensed
and qualified for the flight in accordance with existing
regulations. 3.1.2 The maintenance records indicated that the
aircraft was equipped and maintained
in accordance with existing regulations and approved procedures.
3.1.3 The weather did not contribute to this incident 3.1.4 There
was an effect on Air traffic control 3.2 Probable Cause/s 3.2.1
Mechanical breakdown (thread separation) of adhesion within the
casing repair plug
between the repair rubber and casing cord structure of number 1
tire, during take-off.
3.3 Contributing Factor(s): 3.3.1 Severe operating conditions,
using high airports and maximum performance of the
aircraft. 4. SAFETY RECOMMENDATIONS 4.1 Since the operator
operates under severe operating conditions, it was considered
possible that the maximum performance of the aircraft may have
been beyond the capability of this approved repair process. With
this in mind, it is strongly recommended that the SACAA
Airworthiness Section should examine the possibility of revising
the approved conditions for this repair
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process, especially when these tires are used at high elevation
airports at severe operating conditions.
5. APPENDICES 5.1 Appendix A” – Tire Manufacturer Report.
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Compiled by: JJ du Plessis Date: 30 November 2011 For: Director
of Civil Aviation Investigator-in-charge: JJ du Plessis Date: 30
November 2011 Co-Investigator: N/A Date: N/A