28
CA 12-12a 11 JULY 2013 Page 1 of 28 Section/division Accident and Incident Investigations Division Form Number: CA 12-12a AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference: CA18/2/3/9363 Aircraft Registration ZS-OFJ Date of Accident 25 September 2014 Time of Accident 1105Z Type of Aircraft Robinson R44 Raven II (Helicopter) Type of Operation Commercial Pilot-in-command Licence Type Commercial (Helicopter) Age 30 Licence Valid Yes Pilot-in-command Flying Experience Total Flying Hours 226.6 Hours on Type 98.7 Last point of departure Rand Airport (FAGM) - Gauteng Province Next point of intended landing Rand Airport (FAGM) - Gauteng Province Location of the accident site with reference to easily defined geographical points (GPS readings if possible) Germiston, near industrial area (Jupiter) with GPS co-ordinates reading as: S26º 14' 33", E028º 09' 04" with a field elevation of 5462 ft. Meteorological Information Wind direction: 120; Wind speed: 13 kts, Temp: 25ºC, Dew Point: 01ºC, Visibility: CAVOK Number of people on board 1+1 No. of people injured 0 No. of people killed 2 Synopsis The pilot was accompanied by a passenger (vehicle tracking personnel) on board the helicopter. They were returning from a commercial vehicle tracking flight when the accident occurred. During the approach at approximately one nautical mile heading in a southerly direction to FAGM, the ATC contacted the pilot after seeing the helicopter manoeuvring strangely. Thus, the ATC observed that the helicopter suddenly hovered and then instantly pitched its nose up before diving straight down in a nose-down attitude. The ATC then asked the pilot to confirm if that operation was normal. The pilot responded with an emergency call “MAYDAY”. Immediately after that call, the ATC saw the helicopter descending until it hit the ground. According to the eye witness, the helicopter was observed falling nose-down and it burst into flames immediately after impact. The helicopter was destroyed by fire. The main rotor assembly, tail rotor assembly and the vertical stabilizers were found within a radius of 40 meters from the main wreckage. The investigation determined that the accident was caused by the pilot suddenly stopping and attempting to make a hovering out-of-ground effect manoeuvre. This resulted with the pilot losing control and she was unable to recover from the induced abnormal forward flight hovering attitude. Probable Cause The helicopter entered into a vortex ring state from which the pilot was unable to recover. Contributory Factor/s 1. Sudden hovering out-of-ground effect at a restricted height 2. Situational unawareness 3. Loss of control IARC Date Release Date

Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

Embed Size (px)

Citation preview

Page 1: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 1 of 28

Section/division Accident and Incident Investigations Division Form Number: CA 12-12a

AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY

Reference: CA18/2/3/9363

Aircraft Registration

ZS-OFJ Date of Accident 25 September 2014 Time of Accident 1105Z

Type of Aircraft Robinson R44 Raven II (Helicopter) Type of Operation Commercial

Pilot-in-command Licence Type Commercial (Helicopter)

Age 30 Licence Valid Yes

Pilot-in-command Flying Experience

Total Flying Hours

226.6 Hours on Type 98.7

Last point of departure Rand Airport (FAGM) - Gauteng Province

Next point of intended landing Rand Airport (FAGM) - Gauteng Province

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

possible)

Germiston, near industrial area (Jupiter) with GPS co-ordinates reading as: S26º 14' 33", E028º 09' 04" with a field elevation of 5462 ft.

Meteorological Information Wind direction: 120; Wind speed: 13 kts, Temp: 25ºC, Dew Point: 01ºC, Visibility: CAVOK

Number of people on board 1+1 No. of people injured 0 No. of people killed 2

Synopsis

The pilot was accompanied by a passenger (vehicle tracking personnel) on board the helicopter. They were returning from a commercial vehicle tracking flight when the accident occurred. During the approach at approximately one nautical mile heading in a southerly direction to FAGM, the ATC contacted the pilot after seeing the helicopter manoeuvring strangely. Thus, the ATC observed that the helicopter suddenly hovered and then instantly pitched its nose up before diving straight down in a nose-down attitude. The ATC then asked the pilot to confirm if that operation was normal. The pilot responded with an emergency call “MAYDAY”. Immediately after that call, the ATC saw the helicopter descending until it hit the ground. According to the eye witness, the helicopter was observed falling nose-down and it burst into flames immediately after impact. The helicopter was destroyed by fire. The main rotor assembly, tail rotor assembly and the vertical stabilizers were found within a radius of 40 meters from the main wreckage. The investigation determined that the accident was caused by the pilot suddenly stopping and attempting to make a hovering out-of-ground effect manoeuvre. This resulted with the pilot losing control and she was unable to recover from the induced abnormal forward flight hovering attitude.

Probable Cause

The helicopter entered into a vortex ring state from which the pilot was unable to recover. Contributory Factor/s

1. Sudden hovering out-of-ground effect at a restricted height

2. Situational unawareness

3. Loss of control

IARC Date Release Date

Page 2: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 2 of 28

Section/division Accident and Incident Investigation Division Form Number: CA 12-12a

AIRCRAFT ACCIDENT REPORT

Name of Owner : MIX TELEMATICS

Name of Operator : Henley Air

Manufacturer : Robinson Helicopter Company

Model : R44 Raven II

Nationality : South African

Registration Marks : ZS-OFJ

Place : Germiston; near the Jupiter industrial area with GPS

co-ordinates: S26º 14' 33", E028º 09' 04"and field

elevation of 5462 feet

Date : 25 September 2014

Time : 1105Z

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 produced without prejudice to the rights of the CAA, which are reserved.

1. FACTUAL INFORMATION

1.1 History of Flight

1.1.1 The pilot, accompanied by a passenger (vehicle tracking personnel), departed from

Rand Airport (FAGM) on a commercial vehicle tracking flight in the Pretoria area,

which is north of FAGM. The intention was to land back at FAGM. Approximately an

hour after departure and on the return flight to FAGM, the pilot contacted the ATC at

Page 3: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 3 of 28

FAGM. The helicopter (MATRIX-1) was in the approach towards the FAGM

airspace and heading in a southerly direction. According to the FAGM Tower

recordings at the time, the pilot reported her position to be at approximately five

nautical miles north of FAGM. The pilot was flying over the Linksfield area and was

requesting to join the circuit and land on the heliport next to Hangar 6. The ATC

cleared MATRIX-1 inbound at about 6000 ft above mean sea level (AMSL) and

below to remain north of Runway 29; MATRIX-1 was also asked to report during the

final approach. The pilot read back these ATC’s instructions and duly confirmed

them, in accordance with the standard procedures.

1.1.2 Approximately two minutes later, while still heading in a southerly direction inbound

at 6000 ft to Runway 17, MATRIX-1 contacted the ATC and reported being ready to

cross Runway 29. The ATC denied permission because the aircraft heliport is north

of Runway 29. The runway was in use at the time because a Cessna aircraft (C150)

was doing left circuit training. MATRIX-1 was then instructed to remain north of

Runway 29 and to report when safe on the ground. At this time, the ATC located the

helicopter’s position on the northern side of the airport at approximately one nautical

mile, hovering over the factories in the industrial area. The ATC attempted to ask

the pilot whether the operation was normal as per recall of the initial instruction; at

this point the ATC observed the helicopter suddenly pitching its nose up slightly and

then pitching nose-down. On making contact, the pilot responded with an

“EMERGENCY MAYDAY” call. In the ATC recordings, a horn warning of a low main

rotor RPM could be heard sounding in the background. Refer to Appendices A for

the ATC Matrix transcript.

1.1.3 The eyewitness is an employee in one of the factories in the Jupiter industrial area.

He stated that he observed the helicopter falling in a nose-down attitude with the

engine making a high revving sound prior to impacting the ground; it burst into

flames during the impact, which was on their dumping area. That witness further

stated that after the impact he called some of his colleague and rushed to the

helicopter with chemical fire extinguishers in an attempt to extinguish the fire and

save the occupants; this attempt was unsuccessful.

1.1.4 The airport fire and rescue team was also dispatched after the ATC informed them

of the accident. They arrived at the accident site after approximately 15 minutes and

found that the helicopter was already destroyed by fire. They then extinguished the

Page 4: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 4 of 28

fire and secured the accident side.

1.1.5 The accident occurred in daylight conditions in bushy terrain with GPS co-ordinates:

S26º 14' 33", E028º 09' 04" with a field elevation of 5462 feet.

1.2 Injuries to Persons

Injuries Pilot Crew Pass. Other

Fatal 1 - 1 -

Serious - - - -

Minor - - - -

None - - - -

1.3 Damage to Aircraft

1.3.1 The helicopter was destroyed by the post-impact fuel-fed fire.

Figure 1: The wreckage of the helicopter and the accompanying debris

Page 5: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 5 of 28

1.4 Other Damage

1.4.1 None

1.5 Personnel Information

Nationality South African Gender Female Age 30

Licence Number 0272365735 Licence Type Commercial H

Licence valid Yes Type Endorsed Yes

Ratings Single engine piston, night

Medical Expiry Date 30 May 2015

Restrictions None

Previous Accidents None

Flying Experience:

Total Hours 226.6

Total Past 90 Days 51.6

Total on Type Past 90 Days 11.5

Total on Type 98.7

1.5.1 According to information obtained from the available training records, the pilot did

most of her training towards the south of FAGM, in the Vereeniging area.

Throughout her training the pilot would always request permission to cross Runway

29 on her final approach as the heliport is situated on the northern side of that

runway. The day of the accident was the pilot’s first day on the job with her new

employer. It was also her first flight dispatching on a vehicle tracking flight mission

in the northern region, where she had rarely flown before as a sole flight operator/

commander.

1.5.2 The pilot began training on 28 August 2010 on a R22 helicopter and attained 28.9

hours prior to converting to the R44. She successfully obtained a Private Pilot’s

Licence on 30 September 2011 at 83 flying hours, of which 37.1 hours were flown

on the R22 and 45.9 hours on the R44. On 21 May 2012 the pilot successfully

attained night ratings and this was endorsed on her licence. She obtained her

Page 6: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 6 of 28

Commercial Helicopter Licence on 28 August 2014.

1.6 Aircraft Information

Figure 2: Shows the internet picture of the accident helicopter

Airframe:

Type Robinson R44 Raven II

Serial Number 11147

Manufacturer Robinson Helicopter Company

Date of Manufacture 2006

Total Airframe Hours (At time of Accident) 7732.2

Last MPI (Date & Hours) 22 September 2014 7720.2

Hours since Last MPI Approximately 12

C of A (Issue Date) 16 April 2014

C of A (Expiry Date) 17 April 2015

C of R (Issue Date) (Present owner) 11 April 2009

Operating Categories Commercial ( vehicle tracking)

Page 7: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 7 of 28

Engine:

Type Lycoming IO-540-AE1A5

Serial Number L-28888-48A

Hours since New 31.6

Hours since Overhaul TBO not yet reached

Main Rotor:

Type C016-7

Serial Numbers 3278 & 3280

Hours since New 1195

Hours since Overhaul TBO not yet reached 2200 CRT

Tail Rotor:

Type C029-3

Serial Numbers 2153 & 2154

Hours since New 1195

Hours since Overhaul TBO not yet reached 2200 CRT

Note: The information given in the preceding tables, regarding the main rotor and

the tail rotor blades, indicates the life and retirement time of the components (CRT).

1.6.1 The R44 Raven II is an upgraded version introduced in June 2002 by the Robinson

Helicopter Company. FAA certification was obtained on 10 October 2002 and first

deliveries began in November 2002. The helicopter features a Textron Lycoming

IO-540 engine, 28V 70A electrical system, increased lifting area on the main rotor

blades, and aerodynamic tip caps on the main and tail rotor blades. The helicopter

is designed to perform up to a maximum height of 14000 feet above mean sea

level. According to the available information the helicopter was maintained and

equipped in accordance with the approved procedures.

1.6.2 Weight and balance calculations

The weight and balance were provided by the operator and were captured by the

Page 8: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 8 of 28

pilot prior to the flight. The mass and balance calculation format is provided to the

operator by the manufacturer, Robinson, and it automatically calculates both the

weight and the centre of gravity.

According to the performance and specification of the helicopter type provided by

Robinson, fuel consumption is about 15 gallons per hour in a normal performance

flight. On the day before the accident, 28.6627 US gallons of fuel uplifted on the

helicopter and 30.1156 US gallons of fuel were remaining after the flight. A

maximum allowable take-off weight is 2500 lbs and the helicopter weighed 2125 lbs

prior to the flight. In a flight of approximately one hour the consumption would be

about 15 gallons, as stated above, weighing 89.85lbs. The helicopter had enough

fuel inboard and the weight was within limits at the time of the accident.

WEIGHT & BALANCE FOR R44 ZS-OFJ CATEGORY

ROBINSON HELICOPTER RAVEN II

ITEMS (kg to lbs) Arm (in) Weight (lbs) Moments (lbs-in)

Basic empty weight as equipped 105.9 1 544.0 163 510

Pilot (R seat) 49.5 187 9 257

Forward passenger(L seat) 49.5 220 10 890

Forward baggage 44.0 0 0

Aft passenger and baggage 79.5 0 0

Zero Usable Fuel 94.1 1.951 183.658

Usable fuel at 6 lbs/gal (Main Tank) 106.0 108 11 448

Usable fuel at 6 lbs/gal (Auxillary) 102.0 66 6732

MAUW 80.7 2 500 201 836

All Up Weight (take-off fuel) 95.0 2 125 201 836

Balance 375

Fuel (gal) To be used Available % Full

Main Tank (6 lbs/gal) 18 59

Auxillary Tank (6 lbs/gal) 11 60

Weight Indication

Position of the Centre of gravity

Page 9: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 9 of 28

1.6.3 All the available aircraft documentation was studied and reviewed; these documents

included maintenance records, certificates and service bulletin letters. According to

these records, the aircraft had been equipped and maintained according to the

existing regulations. All service bulletins published by the engine and helicopter

manufacturers had been adhered to and complied with, by the owner and aircraft

maintenance organisations (AMOs).

1.7 Meteorological Information

1.7.1 Meteorological information as obtained from the official weather station:

Wind direction 120º Wind speed 13 kts Visibility CAVOK

Temperature 25ºC Cloud cover None Cloud base None

Dew point 01 ºC

1.8 Aids to Navigation

1.8.1 The helicopter was equipped with the standard factory-fitted navigational equipment

as approved by the Regulator. There were no recorded defects to the navigational

equipment prior to flight.

1.9 Communications.

1.9.1 The helicopter was equipped with one VHF (very high frequency) radio approved by

the Regulator. There were no recorded defects regarding the communication

equipment prior to flight.

1.10 Aerodrome Information

1.10.1 The accident occurred one nautical mile north of Rand Airport (FAGM) at a point

with GPS co-ordinates S26º 14' 33", E028º 09' 04"and a field elevation of 5462 feet

Page 10: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 10 of 28

AMSL.

Aerodrome Location Gauteng, South Africa

Aerodrome Co-ordinates S26º 14' 33", E028º 09' 04"

Aerodrome Elevation 5462 ft.

Runway Designations 11/29 17/35

Runway Dimensions 1712×15m 1493×15m

Runway Used None

Runway Surface Asphalt

Approach Facilities Yes

1.11 Flight Recorders

1.11.1 The helicopter was not equipped with a flight data recorder or a cockpit voice

recorder. Neither of these was required in terms of the relevant aviation regulations.

1.12 Wreckage and Impact Information

1.12.1 The area where the accident occurred is an industrial dumping site surrounded by

bush and old construction concrete material. After the accident, the on-site

observation revealed that the helicopter impacted the ground with a nose-down

flight attitude.

Figure 3: Damage to the tail rotor Figure 4: Damage to the tail stabilizer

Page 11: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 11 of 28

The main rotor impacted with the ground first and detached the whole main rotor

assembly from the main wreckage and was followed by the fuselage which was

consumed by the fire that erupted during impact. Both the vertical stabiliser and the

tail rotor assembly were also detached from the main wreckage.

Figure 5: Damage to the main rotor assembly and main rotor blades

1.12.2 The distribution of the helicopter wreckage was fairly localised within a radius of

approximately 40m from the point of impact. The damage on the main rotor was

consistent with damage attributable to an engine operating at high power. All the

damage was accounted for and was found to be consistent with damage caused by

the high impact forces during the accident sequence.

1.13 Medical and Pathological Information

1.13.1 According to the pathological information, the fatal injuries suffered by the helicopter

occupants were caused by the severe high impact forces inflicted during the

accident sequence and by the fire that erupted after impact.

Page 12: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 12 of 28

1.14 Fire

1.14.1 A post-impact fire occurred during the accident sequence and this consumed the

helicopter fuselage structure.

1.15 Survival Aspects

1.15.1 The accident was not considered to be survivable. The occupants were fatally

injured as a result of the high impact forces imposed during the accident sequence

and the fire that erupted after impact.

1.15.2 The helicopter was equipped with shoulder and harness. These were destroyed by

the fire during the accident sequence. The occupants were found outside the

fuselage next to the helicopter wreckage. It is not known whether both occupants

were making use of the shoulder and harness or whether these failed during the

accident sequence.

1.16 Tests and Research

1.16.1 It was not possible to conduct any in-depth investigation of the helicopter

components because of the damage caused by fire that erupted after impact.

1.16.2 The following points were observed by the ATC prior to the helicopter accident:

The helicopter was hovering out-of-ground effect (OGE) at a restricted height of

600 ft AGL.

The nose of the helicopter pitched up and then a sudden nose-down was

observed before impact; this seemed very consistent with an un-commanded

manoeuvre.

An alarm indicating low main rotor RPM was audible during the last contact of

the emergency call.

The sequence of events described above all occurred within a period of less than

15 seconds, during the second contact of the final approach.

Page 13: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 13 of 28

1.16.3 Rapid Deceleration or Quick stop

Reference: FAA- H - 8083 - 4, Chapter 11, Pages 11-6 & 11-7. See

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/faa-h-

8083-4.pdf

A rapid deceleration, or quick stop, is used to decelerate from forward flight to a

hover. The objective of a rapid deceleration or quick stop is to lose airspeed rapidly

while maintaining a constant heading, ensuring adequate tail rotor to ground

clearance at all times. Quick stops are practiced to improve coordination and to

increase proficiency in manoeuvring a helicopter. As the student gains coordination

and proficiency in the manoeuvre, conduct the manoeuvre with a crosswind. From

previous discussion of aerodynamics, the student should realise that downwind

decelerations or quick stops are not recommended and that every effort should be

made to avoid them.

Instructional Points

During initial training, always perform this manoeuvre into the wind. As discussed

above, once the student has demonstrated sound coordination and proficiency,

conduct training with crosswinds. It is essential for the student to begin crosswind

training with light wind velocities. For the instructor, it is important to know that the

manoeuvre is conducted in in-ground effect (IGE) and just above effective

translational lift (ETL, which facilitate recovery.

Initiate the deceleration by applying aft cyclic to reduce forward speed and

simultaneously lowering the collective, as necessary, to counteract any climbing

tendency. Emphasise to the student that the timing must be exact. If too little down

collective is applied for the amount of aft cyclic applied, a climb results. If too much

down collective is applied, a descent results. A rapid application of aft cyclic

requires an equally rapid application of down collective. As collective pitch is

lowered, apply proper anti-torque pedal pressure to maintain heading and adjust the

throttle to maintain RPM. As the speed dissipates, transition to a hover by lowering

the nose and allowing the helicopter to descend to a normal hovering altitude in

level flight and at zero groundspeed.

Page 14: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 14 of 28

During the recovery, increase collective pitch as necessary to stop the helicopter at

normal hovering altitude, adjust the throttle to maintain RPM, and apply proper

antitorque pedal pressure to maintain heading.

Ensuring that the student understands at all times where the tail rotor is relative to

the ground is the key to success for this manoeuvre. As a teaching point prior to

take off and, if the helicopter RPM allows, have the student sit in the helicopter and

pull the tail boom down until the tail stinger or guard almost touches the surface.

The student then gains the visual picture of the most nose-high attitude in which the

helicopter needs to be in most situations.

Common Student Difficulties

Coordination

Because the quick stop demands a high degree of coordination, the student may

encounter difficulties during the initial attempts. All flight controls are used: the

cyclic to establish the pitch attitude for the desired rate of deceleration, collective to

control altitude, throttle to maintain RPM (if applicable), and antitorque pedals to

control heading. Initial quick stops should be practiced with a gentle deceleration

rate to reduce the amount of control required. As the student gains proficiency,

steepness of the initial flare can be increased until full down collective is required to

prevent an excessive gain in altitude.

Recovery

During the recovery, the helicopter should settle gently toward the hovering altitude.

However, some students fail to recognise the need for recovery action and they

allow the helicopter to settle too rapidly as airspeed diminishes. Late application of

collective requires an abrupt input to stop the rate of descent. As translational lift is

lost and collective is increased, forward cyclic should be applied to return to a level

attitude. In addition, as translational thrust is lost, even more antitorque pedal must

be applied and more power produced to provide the antitorque. If stopping

downwind, LTE ) could occur.

1.16.4 Hover out-of-Ground Effect (OGE)

The following information is extracted from Chapter 3, Aerodynamics of Flight. This

Page 15: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 15 of 28

Chapter provides more details on IGE and OGE hover. Refer to

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/faa-h-

8083-4.pdf

Figure 6: Hover perfomance chart

The hovering out-of-ground effect is basically the same as the hovering in-ground

effect; the main difference is that it will generally require more power than the

hovering in-ground effect.

Performance Charts

According to Robinson the design performance of the helicopter type was approved

by the Federal Aviation Administration.

Page 16: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 16 of 28

Hovering Performance

In developing performance charts, helicopter manufacturers make certain

assumptions about the condition of the helicopter and the ability of the pilot. It is

assumed that the helicopter is in good operating condition and the engine is

developing its rated power. The pilot is assumed to be following normal operating

procedures and to have average flying abilities. The term ‘average’ refers to a pilot

capable of doing each of the required tasks correctly and at the appropriate times.

Using these assumptions, the manufacturer develops performance data for the

helicopter based on actual flight tests. However, they do not test the helicopter

under each and every condition shown on a performance chart. Instead, they

evaluate specific data and then mathematically derive the remaining data.

NB: Performance data presented in this section was obtained under ideal

conditions. Performance under other conditions may be substantially less.

A helicopter’s performance is dependent on the power output of the engine and the

lift produced by the rotors, whether this is produced by the main rotor(s) or tail rotor.

Any factor that affects engine and rotor efficiency will affect performance. The three

main factors that affect performance are density altitude, weight, and wind. These

factors are discussed in great detail in the Pilot’s Handbook of Aeronautical

Knowledge, FAA-H-8083-25.

Every helicopter Pilot Operating Handbook (POH) has hover charts for both the In-

Ground Effect (IGE) and Out-of-Ground Effect (OGE). This information allows the

pilot to predict whether the helicopter will be capable of hovering OGE or not. If the

performance chart indicates that the helicopter is not capable of OGE hovering at

the particular density altitude and weight, then the pilot will either have to plan to

use an IGE hover, or will have to make some other change to enable OGE hover;

this could entail, for example, reducing the weight of the aircraft or waiting until the

temperature is lower.

Basic Concepts

There are many reasons why a helicopter pilot may need to hover out-of-ground

effect. In some instances the pilot will be hovering fairly close to the ground, while

Page 17: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 17 of 28

needing to stay a little higher than 1/2 rotor diameter in altitude. A common reason

might be obstacles that prevent a landing such as tall grass or shrubs. In other

instances, the pilot may be coming to a stop hundreds or thousands of feet above

the ground. Electronic News Gathering (ENG) helicopters do this many times when

filming a breaking news story. The same applies to helicopters involved in external

lift operations.

Helicopter performance centers upon the issue of whether or not the helicopter can

be hovered. More power is required during the hover than in any other flight regime.

Obstructions aside, if a hover can be maintained, a takeoff can be made, especially

with the additional benefit of translational lift. Hover charts are provided that

describe in-ground effect (IGE) hover and out-of-ground effect (OGE) hover under

various conditions of gross weight, altitude, temperature, and power. The IGE hover

ceiling is usually higher than the OGE hover ceiling because of the added lift benefit

produced by the ground effect.

A pilot should always plan an OGE hover when landing in an area that is uncertain

or unverified.

As density altitude increases, more power is required to hover. At some point, the

power required is equal to the power available. This establishes the hovering ceiling

under the prevailing conditions. Any adjustment to the gross weight by varying fuel,

payload, or both, affects the hovering ceiling. The heavier the gross weight, the

lower the hovering ceiling. As gross weight is decreased, the hover ceiling

increases.

Winds

Wind direction and velocity also affect hovering, takeoff, and climb performance.

Translational lift occurs whenever there is relative airflow over the rotor disk. This

occurs regardless of whether the relative airflow is caused by helicopter movement

or by the wind. As wind speed increases, translational lift increases, resulting in less

power required to hover. The wind direction is also an important consideration.

Headwinds are the most desirable as they contribute to the greatest increase in

performance.

Page 18: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 18 of 28

Strong crosswinds and tailwinds may require the use of more tail rotor thrust to

maintain directional control. This increased tail rotor thrust absorbs power from the

engine, which means that there is less power available to the main rotor for the

production of lift. Some helicopters even have a critical wind azimuth or maximum

safe relative wind chart. Operating the helicopter beyond these limits could cause

loss of tail rotor effectiveness. Takeoff and climb performance is greatly affected by

wind. When taking off into a headwind, effective translational lift is achieved earlier,

resulting in more lift and a steeper climb angle. When taking off with a tailwind,

more distance is required to accelerate through translation lift.

Vortex Ring State (or Settling with Power)

Figure 7: Schematic of the vortex ring state

The term “vortex ring state” refers to an aerodynamic condition in which a helicopter

may be in a vertical descent with the application of between 20 percent and

maximum power, and little or no climb performance. The term “settling with power”

arises from the fact that the helicopter keeps settling even though full engine power

is applied. In a normal out-of-ground-effect (OGE) hover, the helicopter is able to

remain stationary by propelling a large mass of air down through the main rotor.

Some of the air is recirculated near the tips of the blades, curling up from the

bottom of the rotor system and re-joining the air entering the rotor from the top. This

phenomenon is common to all air-foils and is known as tip vortices. Tip vortices

Page 19: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 19 of 28

generate drag and degrade air-foil efficiency.

For as long as the tip vortices are small, their only effect is a small loss in rotor

efficiency. However, when the helicopter begins to descend vertically, it settles into

its own downwash, which greatly enlarges the tip vortices. In this vortex ring state,

most of the power developed by the engine is wasted in circulating the air in a

doughnut pattern around the rotor. In addition, the helicopter may descend at a rate

that exceeds the normal downward induced-flow rate of the inner blade sections. As

a result, the airflow of the inner blade sections is upward relative to the disk. This

produces a secondary vortex ring in addition to the normal tip vortices. The

secondary vortex ring is generated about the point on the blade where the airflow

changes from up to down. The result is an unsteady turbulent flow over a large area

of the disk. Rotor efficiency is lost even though power is still being supplied from the

engine.

A fully developed vortex ring state is characterised by an unstable condition in

which the helicopter experiences un-commanded pitch and roll oscillations, has little

or no collective authority, and achieves a descent rate that may approach 6,000 feet

per minute (fpm) if allowed to develop.

A vortex ring state may be entered during any manoeuvre that places the main rotor

in a condition of descending in a column of disturbed air and low forward airspeed.

Airspeeds that are below translational lift airspeeds are within this region of

susceptibility to settling with power aerodynamics. This condition is sometimes seen

during quick-stop type manoeuvres or during recovery from autorotation.

The following combination of conditions is likely to cause settling in a vortex ring

state in any helicopter:

A vertical or nearly vertical descent of at least 300 feet per minute. (Actual

critical rate depends on the gross weight, rpm, density altitude, and other

pertinent factors.)

The rotor system must be using some of the available engine power (20–100

percent).

The horizontal velocity must be slower than effective translational lift.

Some of the situations that are conducive to a settling with power condition are: any

Page 20: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 20 of 28

hover above ground effect altitude; specifically attempting to hover OGE at altitudes

above the hovering ceiling of the helicopter; attempting to hover OGE without

maintaining precise altitude control; pinnacle or rooftop helipads when the wind is

not aligned with the landing direction; and, downwind and steep power approaches

in which airspeed is permitted to drop below ten knots depending on the type of

helicopter. When recovering from a settling with power condition, the pilot tends first

to try to stop the descent by increasing collective pitch. However, this only results in

increasing the stalled area of the rotor, thereby increasing the rate of descent. Since

inboard portions of the blades are stalled, cyclic control may be limited.

Recovery is accomplished by increasing airspeed, and/or partially lowering

collective pitch. In many helicopters, lateral cyclic combined with lateral tail-rotor

thrust will produce the quickest exit from the hazard assuming that there are no

barriers in that direction. In a fully developed vortex ring state, the only recovery

may be to enter autorotation to break the vortex ring state. Tandem rotor helicopters

should manoeuvre laterally to achieve clean air in both rotors at the same time. For

settling with power demonstrations and training in recognition of vortex ring state

conditions, all manoeuvres should be performed at an altitude of 2000–3000 feet

AGL to allow sufficient altitude for entry and recovery.

To enter the manoeuvre, come to an OGE hover, maintaining little or no airspeed

(any direction), decrease collective to begin a vertical descent, and as the

turbulence begins, increase collective. Then allow the sink rate to increase to 300

feet per minute or more as the attitude is adjusted to obtain airspeed of less than

ten knots. When the aircraft begins to shudder, the application of additional up

collective increases the vibration and sink rate. As the power is increased, the rate

of sink of the aircraft in the column of air will increase. If altitude is sufficient, it can

be spent in the vortices to enable the pilot to develop a healthy knowledge of the

manoeuvre.

However, helicopter pilots would normally initiate recovery at the first indication of

settling with power. Recovery should be initiated at the first sign of a vortex ring

state by applying forward cyclic to increase airspeed and/or simultaneously

reducing collective. The recovery is complete when the aircraft passes through

effective translational lift and a normal climb is established.

Page 21: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 21 of 28

Common Errors

1. Too much lateral speed for entry into settling with power.

2. Excessive decrease of collective pitch.

1.17 Organizational and Management Information

1.17.1 This was a commercial flight guided by operation specification G3 under Part 127

AOC which was to expire on 12 November 2014.

1.17.2 The aircraft was maintained, equipped and operated in accordance with existing

regulatory procedures.

1.17.3 Henley Air is contracted to Tele-Matrix with regard to the leasing of the helicopter.

1.17.4 According to the Henley Management, there is an existing contract agreement

between the vehicle tracking company which is at Hangar 7 whereby Henley Air

provides pilots and helicopters for air services during vehicle tracking operations.

1.17.5 According to Henley’s operational manual, Henley Air state that they utilise the

commercial pilot who have attained 100 hours and above as pilot in command and

a minimum of 10 hours on helicopter type.

1.18 Additional Information

1.18.1 According to the ATNS recordings the pilot was cleared for approach at 6000 ft or

below inbounds, and to remain on the northern side of Runway 29. The two routes

indicated in Figure 8, in green and yellow, were permissible for the pilot to execute

subject to the proviso that she was not to cross over into the southern side of

Runway 29. The pilot read that instruction back to ATC and confirmed that she

understood it.

The route along which the pilot was heading was leading towards the intended

destination at Hangar 6 Heliport. This is situated on the left of Runway 17 before its

Page 22: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 22 of 28

intersection with Runway 29. During the follow-up investigation it was clear that

Runway 17 is visible from the location of the accident, where the helicopter was

observed attempting to hover.

Figure 8: An aerial view of the accident site

Figure 9: Heliports at Hangar 6

The ATC who was in control stated that the pilot had the whole of the northern part

Hangar 6 Heliports

Runway 17 approach

Runway 29 approach

Route intended by the pilot

Routes possible for the pilot to take after the ATC’s instruction during first contact to remain North of Runway 29

Page 23: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 23 of 28

of Runway 29 available to execute any positioning manoeuvres but was not allowed

to cross that runway. During the second contact the ATC was surprised when the

pilot reported being ready to cross Runway 29; her voice showed no sign of any

distress. The ATC responded by asking the pilot to remain north of Runway 29 and

to report safe on landing.

1.18.2 After the accident, a text message which the pilot sent a day before the accident

flight to a friend was discovered among the pilot’s colleagues in whom she

expressed nervousness about the shift as it was her first day with her new

employer. The investigating team was advised that the pilot was on her first vehicle

tracking mission as a PIC and it was her first day flying for her new employer. The

pilot flew that mission with the vehicle tracking technician.

Figure 10: View of the aerodrome from the accident site approach

1.18.3 Statements were made by the pilots who flew the helicopter in the period between

the last MPI service and the date of the accident: they all stated that the helicopter

did not show any defects and was serviceable.

1.19 Useful or Effective Investigation Techniques

1.19.1 None

Runway 17

Hangar 6 Helipads

Accident location

Page 24: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 24 of 28

2. ANALYSIS

Man

2.1 The pilot was qualified and licenced for the flight in accordance with existing

regulations. She had received her commercial licence rating less than 28 days

before the accident, however she met the minimum operational requirements

consider for recommended by the company for the type of operation. She send a

text massage to a friend a day before the accident in which she revealed signs of

being nervous prior to the flight; however it was the pilot’s first shift with her new

employer. This is a normal reaction for any pilot or any person doing something for

the first time.

2.2 The pilot contacted the ATC during the final approach and reported being ready to

cross Runway 29. In that communication, the pilot’s voice did not suggest any

distress or panic during the final approach reporting. The ATC denied permission to

cross Runway 29 and asked the pilot to remain north of that runway and to report

safe after landing. Permission was denied because Runway 29 was active with left

hand circuits in progress. However, during the first contact upon approaching

FAGM air-space, the pilot was cleared to approach at 6000 ft and below and to

remain north of Runway 29; the pilot duly read back the instruction and confirmed

that she would act as instructed.

2.3 The approach route taken by the pilot was appropriate as it leads straight to the

intended destination at Hangar 6 Heliport; however the pilot was flying with a

tailwind component at the time. Hangar 6 Heliport is located on the right-hand side

of Runway 29 before the intersection of both runways where the pilot was cleared

area to remain. Aerial photos were later taken from the search helicopter while

hovering over the accident site; these revealed that the pilot was able to see the

airport facilities while approaching at that position.

2.4 After reporting, the pilot observed the surrounding environment and attempted to

correct the routing in accordance with the first command by the ATC. The pilot

executed a quick stop manoeuvre with the helicopter OGE in an attempt to hover

and survey the surrounding environment and then locate the position parameters.

Page 25: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 25 of 28

The pilot’s training record shows that most of her training took place south of the

FAGM aerodrome in an area around Vereeniging. It seems as if the pilot was used

to approaching the aerodrome from the southern side; when making that approach

she would have to ask permission to cross Runway 29. However the pilot stopped

prior to crossing and was involved in an accident. It is possible that when the pilot

noticed the area and recalled the agreement made on the initial contact with the

ATC, she then attempted to correct the routing and in doing so, made a sudden

stop manoeuvre which led to the accident.

The investigator concluded that the pilot’s actions were consistent with someone

who lost awareness of the surrounding environment. In making this conclusion the

investigator noted that the pilot had previously conducted many flights from and to

the FAGM aerodrome.

Machine

2.5 The helicopter was maintained, equipped and operated in accordance with existing

regulatory procedures. During the investigation, statements were made by pilots

who had operated the helicopter during the period between the last maintenance

and the date of the accident: they all confirmed that the helicopter was serviceable.

The damage on both the main rotor blades was inconsistence with damage caused

while the engine was in high power settings.

2.6 The ATC observed the helicopter attempting to hover over the accident site during

the second contact between the ATC and the pilot. The height at which the

helicopter was hovering was insufficient to conduct any risky manoeuvres. When

the ATC attempted to ask the pilot about the operation and whether it was normal in

reference to the initial instructions, the pilot responded with panic in her voice

calling “EMERGENCY MAYDAY”. At that point the ATC observed the helicopter

suddenly pitching its nose up followed by a subsequent nose dive. The pilot

executed a quick stop manoeuvre with a tailwind component. The helicopter flying

handbook advises pilots to refrain from executing this manoeuvre in the conditions

prevailing at the time of the accident.

The sequence of events as described above by the ATC and the witness are with a

helicopter that experienced a vortex ring state. This finding is also supported by the

Page 26: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 26 of 28

fact that the pilot executed a quick stop manoeuvre in an attempt to hover and

assess the environment. The helicopter was OGE at a height of approximately 600

ft AGL while flying with a tailwind component. Although the weight and balance

were within the prescribed limits, the sudden stop manoeuvre with a tailwind

component contributed towards causing the helicopter to settle with power. More

power was required to conduct a hover to prevent settling with power whereby more

power was exhorted by the tail rotor.

This condition requires sufficient distance and height for the helicopter to recover

successfully. Although the engine was heard to be making a high revving sound,

the attitude (nose pointing straight down) in which the helicopter was observed

called for a greater height to recover successfully from the vortex ring state. It was

noted that the horn alarm indicating a low main rotor RPM was sounding at this

time. During intentional or training practice, all manoeuvres should be performed at

an altitude of 2000 – 3000 feet AGL to allow sufficient altitude for entry and

successful recovery.

3. CONCLUSION

3.1 Findings

3.1.1 The pilot was qualified and licenced for the flight in accordance with the existing

regulations.

3.1.2 The pilot adhere to the first command of the ATC personnel, however she lost her

situational awareness.

3.1.3 The second contact between the ATC and the pilot did not indicate any distress

evident in the pilot’s voice.

3.1.4 A text message which the pilot sent the previous day was circulated among

colleagues that indicated that she was nervous prior to the flight.

3.1.5 The helicopter was maintained, equipped and operated in accordance with

regulatory procedures.

Page 27: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 27 of 28

3.1.6 The helicopter impact was nose-first during the accident sequence.

3.1.7 The weather was considered to be a contributing factor to the accident sequence.

Thus, the helicopter was flying with a tailwind component.

3.1.8 The helicopter was destroyed by a post-impact fire.

3.1.9 The helicopter was observed attempting to hover OGE over the accident site prior

to impact, at a height approximately 600 ft AGL.

3.1.10 An audible alarm sound, warning of low main rotor RPM, was heard during the

emergency call prior to impact.

3.1.11 The helicopter entered into a vortex ring state.

3.1.12 The operator complied with his operation manual procedures.

3.2 Probable Cause/s

3.2.1 The helicopter entered into a vortex ring state and the pilot was unable to recover.

3.3 Contributory Factor/s

3.3.1 Sudden hovering out-of-ground effect at a restricted height.

3.3.2 Situational unawareness.

3.3.3 Loss of control.

4. SAFETY RECOMMENDATIONS

5. APPENDICES

5.1 Annexure A

Page 28: Section/division Form Number AIRCRAFT ACCIDENT … and Incidents Reports/9363.pdf · Section/division Accident and Incident ... AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY Reference

CA 12-12a 11 JULY 2013 Page 28 of 28

Appendice A MATRIX 1 and Rand Tower transcript. Pilot ATC Message

Matrix 1 Rand Tower Matrix 1

Rand Tower Matrix 1 Rand tower go-ahead

Matrix 1 Matrix 1 R44, just to the south of …. Request joining

and landing at hangar 6

Rand Tower Matrix 1 QNH 1025 route inbound 6000ft and below,

North of RWY 29 report final approach surface wind

300 ̊ 10kts

Matrix 1 QNH1025 north of RWY 29 inbound 6000ft copy the

wind and will report finals

Matrix 1 Matrix 1 ready to cross RWY29

Rand Tower Matrix 1 remain north of RWY29 report safe on the

ground surface wind 330 ̊ 10kts

Rand Tower Matrix 1 tower

Matrix 1 EMERGENCY! MAY DAY,MAY DAY, MAY DAY,

MAY DAY