ASN logo
ASN Wikibase Occurrence # 178558
Last updated: 26 November 2021
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Time:15:31 LT
Type:Silhouette image of generic S76 model; specific model in this crash may look slightly different
Sikorsky S-76C+
Owner/operator:Bristow Helicopters (Nigeria)
Registration: 5N-BGD
MSN: 76-0540
Fatalities:Fatalities: 6 / Occupants: 12
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:off Oworonshoki, Lagos Lagoon -   Nigeria
Phase: En route
Departure airport:SEDCO Express Offshore Drilling Rig
Destination airport:Lagos-Murtala Muhammed International Airport (LOS/DNMM)
Investigating agency: AIB Nigeria
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.

Sources:$FILE/2015-19-51_Emergency.pdf (EAD) (Preliminary Report) (Interim statement 1) (Interim statement 2)

Accident investigation:
Investigating agency: AIB Nigeria
Status: Investigation completed
Duration: 3 years and 2 months
Download report: Final report
Safety recommendations:

Safety recommendation 2018-001 issued 22 October 2018 by AIB Nigeria to Sikorsky Aircraft Corporation


Revision history:

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