Form Number: CA 12-12a
Occurrence Investigation
Section/division
AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY
Reference:
Aircraft
Registration
Type of Aircraft
ZS-PZZ
Date of Accident
Robinson R44 II Raven (Helicopter)
Commercial Pilot
Licence (CPL)
Pilot-in-command Licence Type
Pilot-in-command Flying
Experience
CA18/2/3/9160
Time of Accident
5 April 2013
Type of
Operation
Age
Total Flying Hours
1630Z
Private Flight
49
Licence Valid
Yes
± 7913,2
Hours on Type
± 2222,5
Last point of departure
Bela-Bela (private airfield) in Limpopo Province
Next point of intended landing
Roedtan (private airfield) in Limpopo Province
Location of the accident site with reference to easily defined geographical points (GPS readings if
possible)
Nylstroom, near Bela-Bela in Limpopo province; GPS co-ordinates: S 24˚44’940” E028˚29’020”.
Meteorological Information
Number of people on
board
Visibility: Low visibility, temperature:17˚, wind gusts: 20 kts, wind speed: 9
kts.
1+0
No. of people injured
0
No. of people killed
1
Synopsis
The pilot was the sole occupant on board the Robinson RH44 helicopter. He flew the helicopter from BelaBela to Roedtan. The pilot lost sight of the ground in the process of avoiding the thunderstorm. A
thunderstorm intercepted the flight path to Roedtan. .The pilot was fatally injured. The helicopter was
destroyed in the accident.
An investigation determined that the pilot may have experienced spatial disorientation from which he could
not recover. It resulted in the helicopter colliding with terrain (controlled flight into terrain – CFIT).
The helicopter was investigated and no abnormality was identified with its operation, hence its operation was
determined to be irrelevant to the accident.
Probable Cause
Controlled flight into terrain (CFIT) due to thunderstorm activity resulting in loss of visibility.
Contributory Factor/s:
Inappropriate flight planning – failure to obtain relevant weather forecast prior to flight.
The pilot did not have an instrument rating, which led to reduced performance and inability to fly the
helicopter in instrument meteorological conditions (IMC) and subsequent spatial disorientation
IARC Date
CA 12-12a
Release Date
25 July 2013
Page 1 of 27
Section/division
Telephone number:
Occurrence Investigation
011-545-1000
Form Number: CA 12-12a
E-mail address of originator:
[email protected]
AIRCRAFT ACCIDENT REPORT
Name of Owner/Operator
Manufacturer
Model
Nationality
Registration Marks
Place
Date
Time
: PLB Computers CC
: Robinson Helicopters Company
: RH44
: South African
: ZS-PZZ
: Nylstroom
: 5 April 2013
: 1630Z
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 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 3 April 2013 at about 1610Z the pilot, being the sole occupant on board a
Robinson RH44 helicopter, was engaged in a private flight from Bela-Bela to
Roedtan. After the helicopter was seen flying from Bela-Bela, it did not reach its
intended destination at its estimated time of arrival (ETA); hence it was reported
missing to the aeronautical rescue co-ordination centre (ARCC). The ARCC then
initiated a search and rescue operation. Due to adverse weather (wind and rain)
and dwindling daylight, the search and rescue operation was suspended until the
next day.
1.1.2 On 4 April 2013 at about 1105Z, the search and rescue operation found the
helicopter, but it had been involved in a fatal accident. The wreckage was located at
the geographical position: S 24˚44.940 E028˚29.020.
1.1.3 An investigation was conducted into the pilot’s flying activities prior to the accident.
During the investigation, witnesses (the pilot’s spouse and a passenger who was
carried on a previous flight) were interviewed. The passenger and spouse stated
the follows:
CA 12-12a
25 July 2013
Page 2 of 27
(i)
First Witness – The pilot’s spouse stated:
During the first flight, the pilot was the sole occupant on board the
Robinson RH44 helicopter. He flew the helicopter from Roedtan to BelaBela. The estimated time of departure from Roedtan was about 0400Z in
the morning.
(ii)
Second Witness – The passenger stated:
He was with the pilot as a passenger on board the helicopter. The pilot
flew the helicopter from Bela-Bela in Limpopo Province to Schoonkloof
Game Farm in Madikwe District in North West province. The purpose of
the flight was to carry out a game capturing operation at the passenger’s
farm.
Immediately when the helicopter arrived at the farm, the pilot commenced
with the operation and the passenger was on board with him. The pilot
was forced to stop the operation temporarily during the afternoon at about
1200Z due to light rain. Later, at about 1230Z until 1450Z, they resumed
the operation. The passenger described the prevailing weather conditions
at the time as raining, visibility fine and windy but not too bad.
The passenger further stated that after they had finished the game
capturing operation, the pilot with him on board flew the helicopter on a
private flight back to Bela-Bela. The passenger disembarked from the
helicopter at Bela-Bela at about 1610Z. The passenger observed the
helicopter taking off and flying in the direction of Roedtan. He indicated
that the weather conditions at Bela-Bela were fine at the time of the flight.
1.1.4
Furthermore, statements were obtained from other persons regarded as
witnesses who stated the following:
(iii)
Third Witness – The motorist stated:
The motorist was driving on the N1 Freeway between Bela-Bela/Settlers
off-ramp and Kromdraai Toll Gate Plaza. He was driving in the direction of
Polokwane at the time. As he looked toward his left side, he briefly saw a
helicopter (identified by its bright yellow colour) flying in the vicinity where
he was driving. The helicopter was flying over the area of the open farm
land on the western side of the N1 freeway. The time was between 1620Z
and 1635Z. The helicopter was heading in a north-westerly direction, flying
below the low cloud base. There was light drizzling rain at the time in the
area. The motorist then focused his attention on the road and continued
his journey, not knowing that moments after seeing the helicopter, the pilot
was involved in an accident.
CA 12-12a
25 July 2013
Page 3 of 27
Figure 1 Google Earth map showing Bela-Bela (departure – Warmbaths Airfield), Bela-Bela/Settler
off-ramp, Kranskop toll gate, Nylstroom Airfield, accident site & Roedtan.
N1 Freeway
to Polokwane
Accident Site
CA 12-12a
25 July 2013
Page 4 of 27
(iv)
Fourth Witness – The farmer stated;
A farmer who was on the farm next to the one on which the helicopter
crashed said that at about 1400Z, the weather conditions turned “bad” in the
vicinity of the farm. “It was raining and the visibility was not good”. Due to the
rainy weather “it was heavily overcast and getting dark”. The identified
weather conditions prevailed until night-time at 1900Z.
1.2
Injuries to Persons
Injuries
Fatal
Serious
Minor
None
1.3
Pilot
1
-
Crew
-
Pass.
-
Other
-
Damage to Aircraft
1.3.1 The helicopter was destroyed in the accident.
Figure 2 Wreckage of the destroyed helicopter. The picture was taken on the day
the helicopter was found. The presence of the clouds in the picture shows the
prevailing adverse weather conditions present on that day.
CA 12-12a
25 July 2013
Page 5 of 27
1.4
Other Damage
1.4.1 None.
1.5
Personnel Information
1.5.1 Pilot-in-Command (PIC):
Nationality
Licence Number
Licence valid
Ratings
Medical Expiry Date
Restrictions
South African
Gender
Male
Age
49
Commercial Pilot
0270512981
Licence Type
Licence (CPL)
Yes
Type Endorsed
Yes
Night, Test Pilot Class 2, Agriculture, Undersling/Winch,
Cull Ratings
31 January 2014
Next ECG due 2015
3 January 2004, Blouberg Mountain, downdraught, RH22 helicopter,
extensive damage.
19 February 2006, Naboomspruit, engine failure on take-off, RH44
helicopter, substantial damage.
Previous Accidents
20 July 2011, Hollandsdrift, engine failure in flight, RH44 helicopter,
extensive damage.
6 December 2012, Rust de Winter, ground collision, RH22 helicopter,
substantial damage.
Flying Experience:
Total Hours
Total Past 90 Days
Total on Type Past 90 Days
Total on Type
± 7913,2
± 120,1
± 120,1
± 2222,5
1.5.2 The flying experience information included in the column above was taken from the
pilot’s “Annual maintenance of pilot licence validity” application dated 14 January
2013. This application was submitted to the South African Civil Aviation Authority
(SACAA) when the pilot was renewing his licence. The application contained the
record of latest flying experience of the pilot.
1.5.3 The pilot’s experience logbook was not found during the investigation. As a result,
the pilot’s exact flying experience (total number of hours flown) at the time of the
accident could not be determined. The flying experience which is missing was from
14 January 2013 until the accident date.
CA 12-12a
25 July 2013
Page 6 of 27
1.5.4 The pilot was engaged in a commercial game culling operation prior to the accident.
Due to the operation it was considered necessary to review the pilot’s flight and duty
time information for the period before and including the accident flight. However, it
was not possible to determine the flight and duty time of previous days because the
flight experience logbook was missing. It was determined that on the day of the
accident, the pilot’s flight time was as follows:
Note: The hours used below in the calculation are based on the witnesses’ accounts
of the sequence of events.
Flight Duty Time – 3 April 2013
Departure & landing
points
Flight from Roedtan to Bela-Bela in
Limpopo orovince
Flight from Bela-Bela to Schoonkloof
Game Farm in Madikwe district in North
West province
Game culling flight at Schoonkloof
Game Farm
Game culling flight stopped - rain
Game culling flight resumed
Flight from Schoonkloof Game Farm to
Bela-Bela
Flight from Bela-Bela till seen by first
witness
Estimated time of accident
Estimated flight time
(UTC)
±06:00 to ±07:00
±1 hour
±07:30 to ±08:30
±1 hour
±09:00 to ±12:00
±3 hours
±12:00 to ±12:30
±12:30 to ±14:50
±15:00 to ±16:10
±30 min
±2 hours 20 min
±1 hour 10 min
±16:15 to ±16:35
±20 min
±16:35 to 16:50
±15 min
±9 hours 5 min
Total
Estimated duration
1.5.5 According to the information above, the pilot flew for approximately 9 hours 5 min
on the day. The second witness (passenger) stated that they were forced to stop
due to bad weather, and it appears that the pilot rested for ±30 min at the time.
1.6
Aircraft Information
Airframe:
Type
Serial Number
Manufacturer
Date of Manufacture
Total Airframe Hours (At time of Accident)
Last MPI (Date & Hours)
Hours since Last MPI
C of A (Original Issue) (Expiry Date)
C of R (Issue Date) (Present Owner)
Operating Categories
CA 12-12a
Robinson R44 II
11970
Robinson Helicopter Company
2007
Still to be determined
18 February 2013
1500,1 hours
Still to be determined
30 November 2007
29 November 2013
11 January 2013
PLB Computers CC
Standard Part 127
25 July 2013
Page 7 of 27
1.6.1 The helicopter was in a container as a new product when imported into the Republic
of South Africa. After its arrival in the country, it was assembled, the mandatory
periodic inspection (MPI) was carried out, the release to service was certified, and
the aircraft was delivered to the pilot and utilised in his operations.
1.6.2 The pilot used the helicopter in commercial operations. He used it in agricultural (crop
spraying and game culling) operations under CAR, Part 127.
1.6.3 Pre-flight Inspection:
1.6.3.1 The pilot operating handbook (POH) checklist for preparing the aircraft for flight is
the method to determine the airworthiness of the aircraft prior to each flight. Thus
a complete pre-flight check should be carried out. Any abnormal findings or
defects should be highlighted and corrected before embarking on the flight.
According to the information obtained in the investigation, the pilot had complied
with the pre-flight requirements in this regard on the day.
1.6.4
Maintenance Requirements:
1.6.4.1 According to the helicopter manufacturer (relevant to maintenance) and regulation
(relevant to oversight), the helicopter was to be subjected to both scheduled (100
hours/12 month interval) and unscheduled (defect rectification) maintenance
inspections. According to the maintenance records obtained in the investigation,
the pilot had complied with the requirements.
1.6.5
Aircraft Documentation:
1.6.5.1 The helicopter was required to carry the following aircraft documentation (e.g.
certificate of registration, certificate of airworthiness, radio station licence, mass
and balance certificate etc.) on board. The aircraft documentation was inspected
to review compliance with applicable requirements. The evidence found shows
that the aircraft documentation carried on board was valid and complied with
applicable regulations.
1.6.6
Aircraft Maintenance Documentation:
1.6.6.1 During the investigation the aircraft maintenance documentation was also
inspected. The evidence found shows that all the maintenance inspections were
conducted in accordance with the manufacturer’s requirements by the responsible
aircraft maintenance organisation (AMO).
1.6.6.2 All the entries made in the maintenance logbooks (airframe and engine) were
found appropriately certified in terms of applicable regulations. There was no
evidence of any open defects (deferred defects) in the maintenance
documentation.
Engine:
Type
Serial Number
Hours since New
Hours since Overhaul
CA 12-12a
Lycoming IO-540-AE1A5
L-32274-48E
Unknown
TBO not reached
25 July 2013
Page 8 of 27
Main and Tail Rotors:
Main Rotor Blades: Serial Number
Tail Rotor Blades: Serial Number
Operating hours:
1.6.7
4433
5836
4435
5839
unknown
Fuel:
1.6.7.1 According to the Robinson RH44 pilot operating handbook (POH), the fuel capacity
of the helicopter in the main tank is 120 litres (116 litres usable) and in the
auxiliary tank 70 litres (69 litres usable) of aviation gasoline (Avgas).
Note: As regards the fuel, four 25-litre plastic drums) were found at the accident
site which had been carried on board the helicopter. The purpose of the
plastic drums was determined to be for carriage of extra fuel for refuelling
during the game capturing operation.
Figure 3 shows the debris of the red plastic drums
1.6.3.2 It was not possible to determine the fuel quantity carried on board the helicopter
prior to or at time of the accident on the basis on the above information. However,
the auxiliary tank was half full (±35 to 40 litres). The main tank was completely
destroyed.
1.6.3.3
According to the first witness (pilot’s spouse), she received a telephone call from
the pilot after he landed at Bela-Bela. The pilot informed her at the time that the
flight from Bela-Bela to Roedtan was going to take ±40 min.
1.6.3.4 Based on the above evidence, the helicopter had sufficient fuel on board for the
flight from Bela-Bela to Roedtan. The fuel was not a contributing factor in the
accident.
CA 12-12a
25 July 2013
Page 9 of 27
1.7
Meteorological Information
1.7.1 The weather information was obtained from South African Weather Services.
According to the SA Weather Service report, reference: ZS-PZZ-2013-04-03, the
meteorological information provided in the report included observational weather
data at or in the vicinity of the helicopter accident site close to the time of the
occurrence.
The observational weather data includes but is not limited to remote sensing
such as satellite data, radar image data and surface data in the form of
METARS which contain weather elements such as:
(i) Dry-bulb and dew point temperatures;
(ii) Wind speed and direction;
(iii) Cloud cover;
(iv) Visibility;
(v) Weather and QNH.
1.7.2 The weather conditions in the vicinity of the accident at Bela-Bela were:
1.7.2.1
Satellite image:
Note: Below is the day natural colour image valid for 1600Z (18:00 local time)
showing information of few minutes before take-off time of the
helicopter from Bela-Bela (Warmbaths Airfield).
Figure 4 Satellite image of weather conditions
CA 12-12a
25 July 2013
Page 10 of 27
1.7.2.1.1 The satellite image shows cloudy conditions with lightning strikes indicating
embedded thunderstorms in the vicinity of the helicopter accident.
1.7.2.2
Radar Image:
Figure 5 Radar image of the weather conditions
1.7.2.2.1 The radar image shows that thunderstorms were observed along the path of the
helicopter on the day of the accident. Showers were observed at Warmbaths
(Bela-Bela) upon departure, with an active storm positioned at approximately 30
km ahead. The direction of movement of the storm was east-south-easterly;
hence it would appear to have intercepted the path of the helicopter somewhere
between 30 km and 70 km ahead.
1.7.3 Surface Conditions:
1.7.3.1 Below are the surface weather conditions observational data for the weather
station at Warmbaths (Bela-Bela).
Wind Gusts
Temperature
20 kts
(10,4 m/s)
17 ˚C
Wind Speed
Humidity
9 kts
(4,6 m/s)
95%
Pressure
Rainfall
887,8 hPa
19,5 to 20 mm
1.7.4 The SA Weather Service report, reference ZS-PZZ-2013-04-03, is attached as
Appendix A.
CA 12-12a
25 July 2013
Page 11 of 27
1.8
Aids to Navigation
1.8.1 The helicopter had standard navigation equipment installed. There was no evidence
of any malfunction or defect experienced with the helicopter navigation equipment in
flight. The navigation equipment was considered to be in a serviceable condition.
1.8.2 Other equipment, which included a geographical positioning system (GPS), was
also carried on board the helicopter. A portable GPS was installed to assist the pilot
with relevant basic navigation information. The GPS was in a serviceable condition
prior to the flight, but was destroyed in the accident and a GPS download was not
possible.
.
1.9
Communications
1.9.1 The helicopter was flown in uncontrolled airspace. The pilot was required to carry
out uncontrolled airspace communication procedures.
1.9.2 The helicopter had VHF King KY 196A radio communication equipment installed.
The radio was destroyed, hence the frequency it was set to is not known. The pilot
did not report any malfunction or defect with the radio equipment prior or during the
flight. The radio was considered to be serviceable.
1.9.3 No evidence of communication from the helicopter with any other aircraft or ATC
was found.
1.10
Aerodrome Information
1.10.1 The helicopter was involved in an accident in an agricultural area away from an
aerodrome. The accident site was in an open field at GPS co-ordinates S
24˚44’940” E028˚29’020”.
1.10.2 The pilot was flying from Bela-Bela with the intention to land at Roedtan. The
distance between the two points is approximately 46 nautical miles (NM).
1.11
Flight Recorders
1.11.1 The helicopter did not have any flight recorders (FDR and CVR) installed and these
were not required by applicable regulations.
1.12
Wreckage and Impact Information
1.12.1 The flight path of the helicopter prior to the impact was from Bela-Bela en route to
Roedtan. The pilot took off in a north-easterly direction. The impact information
indicated that the pilot had initiated a turn to the left which may have directed him
toward Nylstroom. After the turn the helicopter was involved in the accident.
CA 12-12a
25 July 2013
Page 12 of 27
1.12.2 It is evident that immediately after the helicopter impacted the ground, break-up
followed. The wreckage debris was distributed in a straight line from the impact
crater forward to the location where the main wreckage came to a halt. The degree
of destruction and break-up gave a clear indication of the impact heading and
sequence. See picture below showing the wreckage distribution.
First point of impact
(crater)
Tail rotor drive debris =
distance 5 m from crater
Main rotor drive debris =
Distance 70 m from crater
Main wreckage =
distance 80 m from crater
Wreckage distribution = total
distance 80 m, direction ……..Insert
direction!˚
Engine
Figure 6 Wreckage and impact information
1.12.2 During the on-site investigation, the wreckage was examined in order to determine
if there was a structural failure prior to ground impact that contributed to the cause
of the accident. The following ground impact marks indicate that the helicopter hit
the ground while turning/rolling to the left, with the nose pitched down at a fairly low
angle and high velocity:
(i)
CA 12-12a
Main rotor: It is evident from the damage caused to the main rotor blades that
the helicopter was turning/rolling to the left. The main rotor blades first cut the
branches of a tree and ground impact followed. The two main rotor blades tips
then dug into the ground under power, which resulted in a portion of the rotor
breaking off. The broken pieces of main rotor blade tips were found scattered
on the ground near the tree.
25 July 2013
Page 13 of 27
Cut tree
Main rotor blade in ground
Damage to main rotor
Figure 7 Main rotor impact sequence
(ii)
In the sequence of the helicopter ploughing to the ground, it dug a shallow
hole (impact crater) in the ground. The soil of the crater was projected forward
and formed a small rim of soil piling up in the direction of impact. The debris of
the fuselage structure (i.e. windshield, left and right side door frames, left side
skid) was found scattered everywhere around the crater. See figure below:
Left side skid dug into
ground
Ground impact mark of
main rotor blade
Cockpit area debris
1. Cockpit and cabin structure
2. Windshield glass
2. Left and right side door frames
Figure 8 Impact crater and debris
CA 12-12a
25 July 2013
Page 14 of 27
1.13
Medical and Pathological Information
1.13.1 The pilot had a valid Class 1 aviation medical certificate. He was fatally injured in
the accident.
1.13.2 The medico-legal post-mortem examination of the pilot was performed by the
Department of Health, Bela-Bela Forensic Pathology Services on 10 April 2013. The
post-mortem report concluded that the cause of death was multiple injuries
consistent with the aircraft accident.
1.14
Fire
1.14.1 There was no evidence of pre or post-impact fire.
1.15
Survival Aspects
1.15.1 The accident was considered to be not survivable. The helicopter immediately
started to break up after it impacted the ground. The wreckage investigation
showed that the helicopter was turning/rolling to the left when it impacted the
ground. Due to the destruction, it was not possible to positively identify the seat
used and if safety belts and harnesses were used by the pilot. The pilot was fatally
injured. His remains were found approximately 100 metres from the impact crater.
Pilot 100 m
Main wreckage
80 m
Impact crater
Figure 9 Destruction of helicopter related to survivability
CA 12-12a
25 July 2013
Page 15 of 27
1.15.2 According to available information, the helicopter was last seen when it flew from
Bela-Bela at approximately 1610Z on 3 April 2013. When the helicopter did not land
at the destination, it was reported missing to the aeronautical rescue and coordination centre (ARCC). An official search and rescue operation was initiated to
look for the missing helicopter. The search and rescue operation was stopped and
continued again on 4 April 2013 till 1105Z, when the helicopter crash site was
found.
1.16
Tests and Research
1.16.1 After receipt of the South African Weather Services report, it became evident that
the helicopter had flown into a thunderstorm. A decision was then taken not to carry
out any specialised testing of the helicopter equipment.
1.16.2 During the on-site investigation of the wreckage and maintenance documentation, it
was determined that the helicopter was serviceable for the flight. No evidence was
found of any component or part defect or malfunction which required testing, hence
none was done.
1.17.5 Pilotfriend. com, Aviation Medical:
1.17.5.1 “Spatial orientation is defined as being the natural ability to maintain the body
orientation or posture in relation to the surrounding environment at rest and
motion. The three-dimensional environment of flight creates sensory “conflict”
and “illusion”. In aviation, the term means the inability to correctly interpret aircraft
attitude, altitude or airspeed, in relation to the earth or point of reference,
especially after a reference point (e.g. the horizon) has been lost. A pilot who
enters such conditions will quickly lose spatial orientation if there has been no
training in flying with reference to instruments.
It is important to note that the numerous sensory stimuli (visual, vestibular, and
proprioceptive) vary in magnitude, direction, and frequency. Any differences or
discrepancies between visual, vestibular, and proprioceptive sensory inputs will
result in a sensory mismatch that can produce illusions and lead to spatial
disorientation.
E.g. the inner ear contains the vestibular system, which is also known as the
organ of equilibrium which detects changes in angular acceleration and detects
changes in linear acceleration and gravity. Information is then provided to the
brain regarding the body position and movement. A connection between the
vestibular system and the eyes helps to maintain balance and keep the eyes
focused on an object while the head is moving or the body rotating. If the pilot
turns either their aircraft or head in flight, the semicircular canal inside each ear
moves with your head, but the fluid inside it does not move because of its
inertia. As the canal moves, the hairs inside also move with it and are bent in
the opposite direction of the acceleration by the stationary fluid. This hair
movement sends a signal to the brain to indicate that the head has turned. The
problem starts when the pilot continues turning the aircraft at a constant rate (as
in a coordinated turn). In this kind of turn, the fluid inside the canal starts moving
initially, and then friction causes it to catch up with the walls of the rotating
CA 12-12a
25 July 2013
Page 16 of 27
canal. When this happens, the hairs inside the canal will return to their straight
up position, sending an erroneous signal to the brain that the turn has stopped–
when, in fact, the turn continues. If the pilot then starts rolling out of the turn to
go back to level flight, the fluid inside the canal will continue to move (because
of its inertia), and the hairs will now move in the opposite direction, sending an
erroneous signal to the brain indicating that the pilot is turning in the opposite
direction, when in fact, he is actually slowing down from the original turn.
Once the aircraft enters conditions under which the pilot cannot see a distinct
visual horizon, the drift in the inner ear continues uncorrected. If the pilot is not
proficient in the use of flight instruments, he/she may loose control of the aircraft
where during the entire time, the pilot remains unaware that he is turning,
believing that he is maintaining straight flight. Under these circumstances then
starts the illusion due to primarily conditions of unreliable or unavailable external
visual references resulting in false sensations of rotation resulting in the aircraft
being in a catastrophic accident”.
1.17
Organizational and Management Information
1.17.1 Operator:
1.17.1.1 The operator had a valid air service licence issued by the South African Air
Service Licensing Council. The operator was authorised to operate the types G3
and G10 air services and category H2 aircraft.
1.17.1.2 The operator also had a valid Part 127 air operating certificate (AOC). The
helicopter registration, ZS-PZZ, was approved on the AOC for utilisation.
1.17.1.3 According to the operations specification, the operator was approved to perform
the following types of air services:
(i) G3 – Aerial patrol, observation and surveying
(ii) G10 – Game and Livestock culling
(iii) N1 – Transport of passengers.
1.17.1.4 The operator conducted the above identified operations from its main base at
Roedtan in Limpopo Province.
1.17.2 Aircraft Maintenance Organisation (AMO):
1.17.2.1 The helicopter was maintained by an approved aircraft maintenance organisation
(AMO) with an appropriate rating. The AMO maintained the helicopter in
compliance with manufacturer’s and regulatory requirements. No anomalies were
identified with the organisation and management of the AMO involving the
maintenance of the helicopter.
CA 12-12a
25 July 2013
Page 17 of 27
1.18
Additional Information
1.18.1 www.faa.gov, General Aviation Pilot’s Guide to Weather Pre-flight Planning:
“The first major pre-flight task is to perceive the flight environment by collecting
information about current and forecast conditions along the route you intend to
take, and then using the information to develop a good mental picture of the
situation you can expect to encounter during the flight. Because there are many
sources of weather information today, the first challenge is simply knowing where
and how to look for the weather information you need”.
1.18.2
For many South African pilots, the South African Weather Service (SAWS)
remains the most widely used source of comprehensive weather information.
1.18.3
Wikipedia – Instrument Meteorological Conditions (IMC)
“Instrument meteorological conditions (IMC) is an aviation flight category that
describes weather conditions that require pilots to fly primarily by reference to
instruments, and therefore under Instrument Flight Rules (IFR), rather than by
outside visual references under Visual Flight Rules (VFR). Typically, this means
flying in cloud or bad weather. In fact, instrument meteorological conditions are
defined as less than the minima specified for visual meteorological conditions. The
boundary criteria between VMC and IMC are known as the VMC minima, which
are known as "marginal VMC".
It is important not to confuse IMC with IFR (instrument flight rules) – IMC describes
the actual weather conditions, while IFR describes the rules under which the
aircraft is flying. Aircraft can (and often do) fly IFR in clear weather, for operational
reasons or when flying in airspace where flight under VFR is not permitted; indeed
by far the majority of commercial flights are operated solely under IFR.
It is possible to be flying VFR in conditions that are legally considered IMC and
have to rely on flight instruments for attitude control because there is no distinct
external horizon.
1.19
Useful or Effective Investigation Techniques
1.19.1 None.
2.
ANALYSIS
2.1
The helicopter was returning from a commercial agriculture game culling flight from
Schoonkloof Game Farm in Madikwe. The pilot was accompanied by a passenger,
the owner of Schoonkloof Game Farm, and they were flying back to Bela-Bela. The
intention of the flight was to land at Bela-Bela for the passenger to disembark from
the helicopter, and for the pilot to continue to Roedtan.
CA 12-12a
25 July 2013
Page 18 of 27
2.2
The investigation determined that the flight from Schoonkloof Game Farm to BelaBela was uneventful. There were no reports of any defects or malfunctions
experienced during the flight. The observation of the passenger was that the pilot’s
performance during the flight was satisfactory. They landed at Bela-Bela at
approximately 1600Z (18:00) and the passenger disembarked from the helicopter.
The helicopter took off again at about 1610Z (18:10) from Bela-Bela to Roedtan.
The pilot was the sole occupant on board the helicopter on the flight.
2.3
According to the second witness (the pilot’s spouse), she expected the helicopter to
land at Roedtan within approximately 40 minutes, which was what the pilot had
communicated in a telephone conversation earlier before the take-off at Bela-Bela.
However, at the expected time of arrival when the spouse of the pilot realised that
the helicopter was nowhere in sight, she became concerned and the situation was
then immediately reported to the relevant authorities with the intention to look for the
missing helicopter.
2.4
After receiving the information of the missing helicopter, the aeronautical rescue coordination centre (ARCC) initiated a search and rescue operation in the Bela-Bela
area. However, due to the adverse weather (wind and rain) and dwindling light the
search and rescue operation was suspended on the first day. The search and
rescue operation continued the next morning and they found the helicopter at
approximately 1105Z (09:05). The helicopter had been involved in an accident and
the pilot fatally injured.
2.5
There was an investigation to determine the cause of and factors contributing to the
accident. It was deemed necessary to investigate the pilot (man), helicopter
(machine) and environmental issues:
2.5.1 Man:
(i)
The pilot was the owner and approved operator of the helicopter. He had a
valid commercial helicopter pilot’s licence (CPL) and helicopter type rating
was endorsed on it.
(ii)
According to the pilot’s latest flight experience record, he had flown a grand
total of 7913,2 hours and ±2222,5 hours on the Robinson RH44 helicopter .
The evidence of the flight experience and the combination of ratings,
including game culling, endorsed on the licence show the pilot to have been
very experienced.
(iii)
A concern was raised during the investigation concerning the pilot not having
an instrument rating on his licence. There was a possibility that the
helicopter was being operated in instrument meteorological conditions (IMC)
on the day of the accident. As the pilot did not have an instrument rating
endorsed on the licence, he might have lacked the relevant technical and
practical experience to fly the helicopter in the thunderstorm conditions which
prevailed on the day.
CA 12-12a
25 July 2013
Page 19 of 27
(iv)
The pilot had a valid Class 1 aviation medical certificate. His medical history
showed no evidence of any serious medical condition. He was considered to
be medically fit to fly the helicopter on the day. His pathology report
concluded that the cause of death was multiple injuries sustained during the
accident. It was concluded that his medical status did not cause or contribute
to the accident.
(v)
According to the pilot’s accident history, he had been involved in four
previous incidents before this fatal accident. In three of the accidents, he
experienced mechanical problems, and in only one a weather condition
(downdraught) was determined to be the cause. A review of the accident
reports did not show any indication of poor airmanship and the investigations
cleared him of any wrongdoing in terms of his performance.
(vi)
On the day of the accident, the pilot flew the helicopter on an uneventful flight
from Roedtan to Bela-Bela. He carried an extra load of fuel in plastic drums
on board the helicopter. In terms of this flight, the extra fuel would have been
considered to be his cargo. A total of 4 drums of 25 litres each were loaded,
which adds up to 100 litres of extra fuel. The fuel tank found on the scene
had a quantity of fuel sufficient to complete its flight to Roedtan. It was
therefore concluded that the quantity of fuel carried on board the helicopter
was not a contributory factor to the accident.
(vii)
A passenger was carried on board the helicopter on the flight from Bela-Bela
to Schoonkloof Game Farm. According to the passenger, the flight was
uneventful. When arriving at the farm, they immediately proceeded with the
game capturing flight. During this flight the pilot’s performance was perfectly
normal as expected. However, the flight was interrupted briefly due to rainy
weather conditions and resumed again after the rain stopped. According to
the passenger the pilot did not want to take any chances by operating in
unsafe weather conditions (rain), hence the decision to stop the flight. In an
interview, the passenger stated that he did not feel that the behaviour of the
pilot was in any way unsafe during the flight. Instead, his observation was
that the pilot took all safety precautions throughout the flight and
communicated his intentions properly before taking any action.
(viii)
After the pilot had completed the game capturing flight, he flew the helicopter
from Schoonkloof Game Farm to Bela-Bela on an uneventful flight. The
passenger reported that they encountered light rain during the flight. When
reaching Bela-Bela, they landed safely and the passenger disembarked from
the helicopter. The pilot then called his wife on his mobile phone and asked
her about the weather conditions in the Roedtan area. According to the wife,
her response to the pilot was that the weather was fine. The pilot then started
the helicopter and flew in the direction of Roedtan.
CA 12-12a
25 July 2013
Page 20 of 27
2.5.2 Machine:
(i)
The helicopter was maintained by an approved aircraft maintenance
organisation (AMO). The helicopter was last serviced (MPI) less than two
months before the accident. According to maintenance records (logbooks),
during the servicing both scheduled and non-scheduled maintenance were
carried out. After the service was completed, the aircraft was certified
serviceable and released to service.
(ii)
The pilot operated the helicopter safely without incident prior to the accident.
The aircraft and maintenance documentation were reviewed during the
investigation. The aim of the review was to determine if there was any history
of a defect or malfunction that was experienced with the helicopter. There
was no evidence of any defect or malfunction. The maintenance information
and the absence of any mention of defects or malfunction show that the
helicopter was in a serviceable condition up to the time of the crash.
(iii)
According to available information, the pilot received the helicopter after the
maintenance and immediately started to fly. As his flight experience logbook
was missing and the flight folio not updated, it was not possible to determine
the hours flown on the helicopter before the crash. However, based on
information obtained from different sources (the passenger, wife and eye
witnesses), ±9 hours 5 minutes were flown on the day of the crash.
(iv)
The evidence of the wreckage and the impact information show that the
helicopter impacted the ground while initiating a left turn towards Nylstroom.
After the helicopter entered the turn, it started losing altitude and impacted
the ground in that attitude. Immediately after the helicopter impacted the
ground, break-up followed, and debris was found scattered in a straight line
approximately 80 m from the impact crater to the main wreckage.
(v)
The wreckage was examined during the investigation. The evidence showed
that there was no structural failure prior to the ground impact. The helicopter
hit the ground in a nose-down attitude at a fairly low angle and high velocity.
The engine sustained substantial damage in the accident and could not be
examined. However, it was deemed necessary to determine whether the
engine was under power at time of impact or not. For this reason the
carburettor was removed from the engine and inspected on site. The
evidence of the carburettor showed that during this time the main rotor
blades were turning at maximum speed. The blades cut a tree and impacted
the ground, resulting in substantial damage.
2.5.3 Environment
(i)
CA 12-12a
The aviation industry is specifically sensitive to weather, thus it is important
for every pilot to ensure that they obtain accurate weather forecast
information before embarking on any flight to ensure their personal safety
and/or damage to property. The pilot has an obligation to be aware of the
weather forecast over the specific areas where he will be operating. Pilots
therefore use certain primary outlets or sources (i.e. newspapers, television,
radio or internet) for weather forecasts. Also, they may obtain such
25 July 2013
Page 21 of 27
information from government agencies (e,g. South African Weather Service),
which are mandated to provide weather forecast information to the public.
The weather forecast is then used to plan and make informed safety
decisions when embarking on the flight. The same was required from the
pilot involved in the accident on the day in question.
(ii)
No evidence could be found to show that the pilot had obtained an official
weather forecast for Bela-Bela when departing for Roedtan. No evidence
could be found to show the pilot had obtained a weather forecast for
Schoonkloof Game Farm in Madikwe when departing Bela-Bela. On both
these flights, the evidence is that the pilot landed safely and the flight was
uneventful.
(iii)
At Schoonkloof Game Farm in Madikwe, during the game capturing
operation, the pilot had to stop flying due to rain. If he had obtained a
weather forecast, he would most probably have known or been aware that at
some point in time during the operation in Madikwe his flight was going to be
interrupted due to rain. This means that the pilot would have consciously
made the decision to fly to Madikwe irrespective of the possibility of rain; or
maybe he was not at all aware of the information that it was going to rain
there that day. If the latter assumption is true, it means that no weather
forecast was obtained for Madikwe. It is known that after the rain had
stopped, he continued with the game capturing operation.
(iv)
After completing the game capturing operation in Madikwe, the pilot
accompanied by a passenger embarked on a flight back to Bela-Bela. Again
in this instance, it was incumbent on him to obtain relevant weather forecast
information for Bela-Bela. No information could be obtained in the
investigation to prove that a weather forecast was obtained before the flight.
According to the passenger, the flight to Bela-Bela was uneventful and the
weather was fine when they landed.
(v)
The pilot’s wife stated that after the pilot had landed at Bela-Bela, she
received a call from him enquiring about the weather conditions present at
Roedtan. The wife informed the pilot that the weather was fine, after which
he then took off for Roedtan. It is evident, based on discussions with the
wife, that the determination of the weather being fine was made purely on
her perception of what she observed outside and not based on a weather
forecast obtained from one of the above sources. Without the latter, she
could not know what the weather forecast would be en route to Roedtan.
(vi)
Apart from obtaining the weather information from his wife, there is no proof
that the pilot used any of the identified sources to verify what he had been
told. The evidence found shows that after he had made the call to his wife
and received the information, he immediately took off and flew in the
direction of Roetan. He was not aware of the severe and hazardous weather
ahead of him en route to Roedtan. The evidence of this can be seen in the
official weather report obtained following the accident.
CA 12-12a
25 July 2013
Page 22 of 27
(vii)
The weather radar images on the South African Weather Services official
report shows the presence of thunderstorms along the path of the helicopter.
Showers were observed at the time the helicopter departed from Bela-Bela
(Warmbaths), with an active storm positioned approximately 30 km ahead.
The direction of the movement of the storm was east-south-easterly, hence it
would appear to have intercepted the path of the helicopter. The Weather
Service found evidence of wind gusts at 20 kts (10,4 m/s), a wind speed of 9
kts (4,6 m/s) and rainfall measured at 19,5 to 20 mm.
(viii)
Based on the information that the pilot inadvertently flew the helicopter into a
thunderstorm, it was deemed important to carry out further research to
understand the consequences of flying into a thunderstorm. For that reason,
research was done and the following was determined:
“A thunderstorm, also known as an electrical storm, a lightning storm,
thundershower or simply a storm, is a form of turbulent weather
characterized by the presence of lightning and its acoustic effect on the
earth's atmosphere known as thunder.
The meteorologically assigned cloud type associated with the thunderstorm
is the cumulonimbus. Thunderstorms are usually accompanied by strong
winds, heavy rain and sometimes snow, sleet, hail, or no precipitation at all”.
Based on the research information and evidence of the Weather Services
report, it is evident that the pilot was facing a very unsafe condition in the
thunderstorm.
(ix)
The above effects of a thunderstorm (turbulence, reduced visibility, lightning,
precipitation and air pressure changes) on the performance of the pilot and
his ability to fly the helicopter may have caused the pilot to experience spatial
disorientation due to lack of instrument flying experience, i.e. inability to
correctly interpret the helicopter attitude, altitude or airspeed in relation to the
earth or point of reference, especially when the point of reference was lost.
The result may have been a sensory mismatch producing an illusion and
leading to spatial disorientation. The illusion resulted primarily from unreliable
or unavailable external visual references, resulting in false sensations of
rotation in the helicopter that led to a catastrophic accident.
3.
CONCLUSION
3.1
Findings
3.1.1 The pilot had a valid commercial pilot’s licence (CPL), having the helicopter
(Robinson R44) type rating endorsed on it.
3.1.2 The pilot had a valid aviation medical certificate, with restriction of ECG due 2015.
There was no other known medical condition which the pilot suffered and which
might have prevented him from flying on the day. The pilot was considered to be
medically fit at the time.
CA 12-12a
25 July 2013
Page 23 of 27
3.1.3 The pilot, being the sole occupant on board the helicopter, flew it on a private flight
from a farm near Bela-Bela toward a farm at Roedtan. According to the witness that
last saw the aircraft, the helicopter was flying from Bela-Bela in a north-easterly
direction toward Roedtan.
3.1.4 When the pilot did not reach his destination at Roedtan, he was reported missing to
the relevant authorities, which resulted in a search and rescue operation being
launched to look for the missing helicopter.
3.1.5 The helicopter was missing from about 1630Z on 3 April 2013 to 1400Z on 4 April
2013, when it was found by the search and rescue operation.
3.1.6 The helicopter was found lying at geographical position: S 24˚44’940” E028˚29’020”.
It had been involved in an accident and completely destroyed.
3.1.7 The accident was considered to be not survivable due to total destruction of
helicopter. The pilot was fatally injured.
3.1.8 The helicopter wreckage indicated that the helicopter was turning or rolling to the
left in a south-westerly direction at a low impact angle and high velocity when it
impacted a big thorn tree and the ground. A total break-up followed.
3.1.9 The debris was spread along a straight line from first point of impact over a distance
of approximately 80 to 100 metres up to where the last pieces were found.
3.1.10 The wreckage was examined during the on-site investigation. No evidence was
found of any mechanical failure or damage to components or parts caused prior to
or during the flight which could have be contributed to the accident.
3.1.11 The wreckage was examined to determine if it had sufficient fuel for the flight. The
evidence found was that the main fuel tank was completely destroyed; therefore it
was not possible to determine if there was any fuel in it prior to the impact. The
auxiliary fuel tank was found fairly intact and contained sufficient fuel (±30 litres).
3.1.12 Several witnesses were interviewed during the investigation.
(i)
The second witness (passenger) was flying with the pilot from Bela-Bela to
Schoonkloof Game Farm in Madikwe and back. His observation was that
there was no notable abnormality in the performance of the pilot on the day.
He said the weather was fine when the pilot left Bela-Bela.
(ii)
The first witness (pilot’s wife) stated that the pilot had called her prior to takeoff from Bela-Bela to enquire about the weather conditions. She told him that
the weather was fine in Roedtan.
(iii)
The third witness (motorist) on the N1 Freeway had seen the helicopter flying.
He said there was low cloud and light drizzling rain at the location where the
helicopter was seen.
CA 12-12a
25 July 2013
Page 24 of 27
(iv)
The fourth witness, the farmer on the farm next to where the accident
occurred, stated said that the weather conditions turned out to be “bad” in the
vicinity of the farm. It was raining and the visibility was not good. It was
heavily overcast and getting dark.
3.1.13 The South African Weather Service submitted a report to the SACAA. The report
stated the following: “METAR from nearby Thabazimbi Station shows light winds on
the ground and moist conditions over the area at the time. The possibilities for low
visibility and gust conditions over the area of accident are very high considering the
presence of thunderstorm activities in the area”.
3.1.14 The Weather Service report further stated: “The direction of movement of the storm
was east-south-easterly; hence it would appear to have intercepted the path of the
helicopter somewhere between 30 km and 70 km ahead”.
3.1.15 According to the research article, “thunderstorms are usually accompanied by
strong winds, heavy rain and sometimes snow, sleet, hail, or no precipitation at all”.
This research information is consistent with the information provided by the Weather
Services report, namely thunderstorm conditions with wind gusts at 20 kts (10,4
m/s), wind speed of 9 kts (4,6 m/s) and rainfall measured at 19,5 to 20 mm, which
can be considered to be instrument metrological conditions (IMC) at the time.
3.1.16 According to another research article, “the effect of a thunderstorm on the
performance of the pilot and his ability to fly the aircraft would be turbulence,
reduced visibility, lightning, air pressure changes and precipitation. These effects
could result in the pilot quickly loosing spatial orientation”. In order to handle the
situation of spatial orientation, he needed training in instrument flying.
3.1.17 The pilot did not have instrument flying (IF) endorsed on his licence. This means
that he was ill equipped in instrument flying and unable to deal with the spatial
disorientation when the thunderstorm intercepted his flight path.
3.1.18 The spatial disorientation could have resulted in a sensory mismatch that produced
illusions and led to the fatal accident.
3.1.19 The evidence found during the investigation was that the helicopter turned/rolled to
the left before impacting the ground. The information is consistent with the research
suggesting that the pilot probably experienced spatial disorientation and an illusion
primarily due to unreliable or unavailable external visual references, resulting in a
false sensation of rotation followed by a catastrophic accident.
3.2
Probable Cause/s
3.2.1 Controlled flight into terrain (CFIT) due to thunderstorm activity resulting in loss of
visibility.
Contributory Factor/s
3.2.2 Inappropriate flight planning – failure to obtain relevant weather forecast prior to
flight.
CA 12-12a
25 July 2013
Page 25 of 27
3.2.3 The pilot did not have an instrument rating, which led to reduced performance and
inability to fly the helicopter in instrument meteorological conditions (IMC) and
subsequent spatial disorientation
4.
SAFETY RECOMMENDATIONS
4.1
None
5.
APPENDICES
5.1
Appendix A: South African Weather Service Report
5.2
Appendix B: Wikipedia article about thunderstorms:
CA 12-12a
25 July 2013
Page 26 of 27
Appendix B: Wikipedia article about thunderstorms:
“A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or
simply a storm, is a form of turbulent weather characterized by the presence of lightning and
its acoustic effect on the earth's atmosphere known as thunder.
The meteorologically assigned cloud type associated with the thunderstorm is the
cumulonimbus. Thunderstorms are usually accompanied by strong winds, heavy rain and
sometimes snow, sleet, hail, or no precipitation at all.
A typical thunderstorm over a field
Thunderstorms may line up in a series or rainband, known as a squall line. Strong or severe
thunderstorms may rotate, known as supercells. While most thunderstorms move with the
mean wind flow through the layer of the troposphere that they occupy, vertical wind shear
causes a deviation in their course at a right angle to the wind shear direction.
Thunderstorms result from the rapid upward movement of warm, moist air. They can occur
inside warm, moist air masses and at fronts. As the warm, moist air moves upward, it cools,
condenses, and forms cumulonimbus clouds that can reach heights of over 20 km (12.45
miles). As the rising air reaches its dew point, water droplets and ice form and begin falling
the long distance through the clouds towards the earth's surface. As the droplets fall, they
collide with other droplets and become larger. The falling droplets create a downdraft of air
that spreads out at the earth's surface and causes strong winds associated commonly with
thunderstorms”.
Effects of thunderstorms on aircraft performance:
There are several hazards associated with thunderstorms which have a negative impact on
the aircraft in flight. Hence pilots should be extremely careful not to fly in conditions of
thunderstorms because of the severity associated hazards, thus it is important to timeously do
weather forecasting to ensure safety. Below are some effects of thunderstorms:
Turbulences; the severe up and down drafts resulting in strong vertical and horizontal lowlevel wind shear conditions capable of disastrously upsetting the flight of an aircraft.
Reduced visibility; the reduction in visibility both horizontally (due to precipitation e.g.
showers of rain, snow and hail) and vertically (due to obscuring cloud e.g. cumulonimbus).
Lightning; high-current electrical within cloud or cloud-to-ground discharged that could
potentially cause damage to the aircraft. It may have an effect of temporarily blinding the pilot
during the lightning strike. The lightning strikes emit destructive radio waves
Precipitation; extreme rainfall which reduces visibility.
CA 12-12a
25 July 2013
Page 27 of 27