ASN Wikibase Occurrence # 178558
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| Date: | Wednesday 12 August 2015 |
| Time: | 15:31 LT |
| Type: |  Sikorsky S-76C+ |
| Owner/operator: | Bristow Helicopters (Nigeria) |
| Registration: | 5N-BGD |
| MSN: | 760540 |
| Year of manufacture: | 2003 |
| Fatalities: | Fatalities: 6 / Occupants: 12 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | off Oworonshoki, Lagos Lagoon -
 Nigeria
|
| Phase: | En route |
| Nature: | Offshore |
| Departure airport: | SEDCO Express Offshore Drilling Rig |
| Lagos-Murtala Muhammed International Airport (LOS/DNMM) | |
| Investigating agency: | AIB Nigeria |
| Confidence Rating: |  Accident investigation report completed and information captured |
A Sikorsky S-76C+ crashed into the Lagos Lagoon in the Oworonshoki area of Lagos. Visual meteorological conditions prevailed at the time and a VFR flight plan was filed. The two flight crewmembers and four of the ten passengers were fatally injured. The helicopter was destroyed and there was no fire.
Preliminary flight recorder data indicated that at 1000ft and 120Kts, the helicopter experienced sudden pitch up, and left roll with varying attitude of yaw, roll and pitch for 12 seconds until it impacted water at about 1531hrs.
FAA emergency airworthiness directive (EAD) 2015-19-51 had been issued 14 September 2015 for a one off inspection and a new requirement for the introduction of 'slippage marks': "During preliminary investigation, a failed servo input control pushrod (pushrod) assembly was identified. Separation of the pushrod tube and the control rod end with bearing was found. This EAD requires inspecting the main rotor (M/R) forward, aft, and lateral pushrod assemblies, the tail rotor (T/R) pushrod assembly, and the jamnuts, and applying slippage marks across the pushrod tubes and jamnuts. These EAD actions are intended to prevent loss of M/R or T/R flight control and subsequent loss of control of the helicopter."
Two recommendations were issued on 21 Sept 2015 in the Preliminary Report:
Interim Safety Recommendations-2015-009 : "Sikorsky Aircraft Corporation should consider a redesign of the affected control pushrod assembly by introducing additional wire locking safety features between the Jamnut and the Pushrod to enhance better security".
Interim Safety Recommendations-2015-010: "Nigerian Civil Aviation Authority (NCAA) should immediately carry out appropriate oversight action on all the Sikorsky S-76 series helicopters flying in Nigeria to ensure the implementation of the Emergency Airworthiness Directives (EAD) and Alert Service Bulletin (ASB) issued by FAA and Sikorsky Aircraft Corporation."
On 12 August 2016 the AIB issued an interim statement:
"AIB has virtually completed all investigative actions and has initiated a follow-up action on interim safety recommendations-2015-009 with Sikorsky through National Transportation Safety Board, NTSB. The draft report will soon be sent to stakeholders for review and comments within 60 days."
The KNKT comment on similarities to the accident to PK-FUP several months earlier in their final report on that accident.
On 22 October 2018 the AIB issued their final report:
Causal Factor:
The separation of the Forward Servo Clevis Rod Assembly from the bearing and Jam nut (Bell Crank Assembly) which is part of the Cyclic Control System responsible for stabilizing the attitude of the helicopter made the aircraft uncontrollable.
Contributory Factors:
1. The absence of a secondary mechanical locking system (lock-pin or wire-lock) in the design of the Forward Servo Input Control Rod assembly contributed to the separation of the Forward Servo Clevis Rod from the bearing and Jam nut.
2. The wear that was prevalent at the Forward Servo Clevis Rod end fitting shank, which made the Jam nut rotate freely when force is applied.
Accident investigation:
 |
|
Sources:
http://www.airliners.net/photo/Bristow-Helicopters-Nigeria/Sikorsky-S-76C/1476955/M
http://bristowgroup.com/bristow-news/latest-news/2015/bristow-helicopter-involved-accident/
http://www.bristowgroup.com/bristow-news/latest-news/2015/update-bristow-helicopter-accident-lagos/
http://aib.gov.ng/files/BRISTOWHELICOPTERS130815.pdf
http://aib.gov.ng/files/BLACKBOXBRISTOW140815.pdf
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/57588a154dcf9f6186257ec00076fb60/$FILE/2015-19-51_Emergency.pdf (EAD)
http://www.aib.gov.ng/media/1034/prebristowhelicopters12082015.pdf (Preliminary Report)
http://www.aib.gov.ng/media/1063/bhnl-first-interrim-statement.pdf (Interim statement 1)
http://www.aib.gov.ng/media/1119/bhnl-second-interim-statement.pdf (Interim statement 2)
http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2015%20-%20008%20-%20PK-FUP%20FINAL%20Report.pdf
Media:
Third Mainland helicopter crash first image from the scene.... pic.twitter.com/AY2u9x0usi
— Ben Ehimen Iyoha (@BenIyoha01) August 12, 2015Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 12-Aug-2015 16:22 | harro | Added |
| 12-Aug-2015 18:21 | rotorspot | Updated [Time, Operator, Total fatalities, Source, Damage] |
| 12-Aug-2015 18:24 | harro | Updated [Operator, Total fatalities, Total occupants, Other fatalities, Location, Phase, Departure airport, Embed code, Narrative] |
| 12-Aug-2015 20:12 | Aerossurance | Updated [Aircraft type, Registration, Cn, Nature, Source, Embed code, Narrative] |
| 12-Aug-2015 20:14 | Aerossurance | Updated [Time, Departure airport, Destination airport, Narrative] |
| 12-Aug-2015 20:19 | Aerossurance | Updated [Departure airport] |
| 13-Aug-2015 06:28 | Geno | Updated [Source] |
| 13-Aug-2015 14:46 | Aerossurance | Updated [Total fatalities, Source] |
| 14-Aug-2015 17:01 | Aerossurance | Updated [Departure airport, Source] |
| 15-Aug-2015 13:18 | Aerossurance | Updated [Source] |
| 21-Sep-2015 18:21 | harro | Updated [Time, Source, Narrative] |
| 28-Mar-2016 13:09 | Aerossurance | Updated [Source, Narrative] |
| 11-Sep-2016 08:11 | Aerossurance | Updated [Other fatalities, Departure airport, Source, Narrative] |
| 31-Aug-2017 14:53 | Aerossurance | Updated [Source] |
| 24-Sep-2017 11:49 | Aerossurance | Updated [Source] |
| 24-Sep-2017 11:53 | Aerossurance | Updated [Source, Narrative] |
| 06-Aug-2018 14:33 | Aerossurance | Updated [Source, Narrative] |
| 22-Oct-2018 19:17 | harro | Updated [Narrative, Accident report, ] |
Corrections or additions? ... Edit this accident description
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