PRELIMINARY REPORT ON ACCIDENT INVOLVING SIKORSKY S-76C+ HELICOPTER BELONGING TO BRISTOW HELICOPTERS NIGERIA LIMITED WITH REGISTRATION 5N-BGD WHICH OCCURED AT OWORONSHOKI AREA OF LAGOS ON THE 12TH OF AUGUST, 2015.
REGISTERED OWNER AND OPERATOR: Bristow Helicopters Nig. Ltd.
PLACE OF ACCIDENT: Oworonshoki, Lagos.
DATE AND TIME: 12TH of August, 2015 at about 1531hrs.
LOCATION: Oworonshoki area of Lagos. Lat: 60 31’
54” N and Long: 30 26’ 16” E.
(All times in this report are
local time, equivalent to UTC+1,
unless otherwise stated)
- Factual Information.
1.1 History of the Flight.
On 12th August, about 1531hrs, 5N-BGD, Sikorsky S-76C+, a domestic chartered flight operated by Bristow Helicopters Ltd (Nigeria), crashed into the Lagoon at 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.
The departure point was an offshore oil rig (SEDCO Express) and the destination was Murtala Muhammed Airport (DNMM), Lagos.
The accident occurred when 5N-BGD was on the inbound flight of a round trip that originated from Lagos. On the outbound flight, 5N-BGD arrived SEDCO Express at about 1448hrs reportedly without incident with two passengers. This was also the first flight of the day and the helicopter did not re-fuel for the trip back to Lagos. The mobile drilling platform was located at Lat: 050 40.9’ N; Long: 0040 23.56’ E, 85 NM from Lagos.
5N-BGD departed SEDCO Express about 1455hrs with twelve souls on board including two crewmembers with endurance of 1 hour 30 minutes and initially maintaining 3,000ft. The estimated arrival Lagos was 1536hrs according to the crew information before departure from the rig.
According to Air Traffic Controller’s transcript, the flight first contacted Lagos at 1524:58hrs and at 1525:15hrs, the Controller acknowledged and said “5NBGD go ahead”. At 1525:18hrs the pilot responded “BGD is from the SEDCO Express approaching 1,000ft and the airfield would be at 1535hrs with twelve souls endurance now one hour and 10 minutes of fuel. At 15:25:36 the controller asked the pilot “Confirm the field at 1535hrs” and the pilot answered “Affirmative GD”. The flight was thus cleared to descend to 1,000ft, QNH 1015 and to report field in sight.
At 1530:19hrs, the helicopter contacted the controller and reported the field in sight. At 1530:23hrs, the controller instructed the pilot to report left downwind for runway 18L. The pilot replied “WILCO GD” at 1530:25hrs. There were no further transmissions from the pilots.
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.
1.2 Injuries to Persons.
1.3 Damage to Aircraft.
The helicopter was destroyed by impact forces with water.
1.4 Other Damage.
1.5 Personnel Information:
Date of Birth – 5th January, 1978
Nationality – American
Licence No. – 5419 ATPL (H)
Medical Expiry – 24th October, 2015
Total Flight Hours – 5,406:36hrs
Total Flight (PIC) – 1,077:45hrs
Total Flight (Type) – 1,077:45hrs
1.5.2 First Officer.
Date of Birth – 4th July, 1989
Nationality – Nigerian
Licence No. – 6617 CPL (H)
Medical Expiry – 31st March, 2016
Total Flight Hours – 808hrs
Total Flight (SIC) – Not Available
Total Flight (Type) – 570hrs
1.6 Aircraft Information:
1.6.1 General Information
Type : S-76C+
Manufacturer : SIKORSKY
Airframe time : 10,258:09hrs
Cycles : N/A
Serial No. : 760540
Year of Manufacture : 2003
1.6.2 Power Plant.
Engine Model: Turbomeca Arriel 2SI
Serial No. : 20737TEC
Hours : 6414:37
Cycles : 7097((N1)/5313.2(N2))
Serial No. : 20745TEC
Hours : 5815:49
Cycles : 5998.1((N1)/5235.3(N2))
A-Check 50hrs was carried out on the 10th of August, 2015 on the aircraft.
Type of Fuel Jet A1
1.7 Meteorological Information.
Time : 1430 UTC
Wind : 200/09 KTS
Visibility : 10 KM
Weather : NIL
Cloud : Broken 360M
Temp./Dew point : 29/220 C
QNH : 1015hPa
Trend : No Significant Weather
The Helicopter was fitted with Solid State Combined CVR/FDR, with a common part and serial number. However, a separate Cockpit Voice Recorder was also installed on the helicopter. The recorders were recovered by professional divers in good condition from the Lagoon on the second day of the accident but the combined recorder had few punctures. The recorders were sent to Air Accident Investigation Branch UK for data download. During the download at the AAIB it was discovered that the combined Solid State Voice/Flight Data recorder only contained information of the flight data while the separate Cockpit Voice Recorder contained audio data. However, they were both successfully downloaded and are now being analyzed.
Solid State Combined Voice/Flight Data Recorder.
Model : SCR 500-660
Part Number : 299402-0100
S/N : 02SRP156
Manufacturer : British Aerospace System & Equipment
Cockpit Voice Recorder.
Model : FA 2100
Part Number : 2100-1010-00
S/N : 000579228
Manufacturer : L3 Communication
Fig. 6 The Recorders
Fig. 7 Recorders being immersed in fresh water for preservation.
Neither the crew nor the passengers had the opportunity to either inflate their respective life jackets or deploy the raft. The crew did not make a MAY DAY distress call, before the helicopter crashed into the Lagos Lagoon around Oworonshoki area at about 1531hrs. The crash site was at Lat: 60 31’ 54” N and Long: 30 26’ 16” E.
According to eyewitness account, the rescue was prompt since there were local fishermen around the crash vicinity. One of the survivors provided a graphic account of how he was pulled out of the water by a fisherman.
Six passengers were rescued alive and four fatalities recovered on 12/08/2015. The flight crew were recovered the next day on the 13/08/2015 both fatally injured.
National Emergency Management Agency (NEMA) led the rescue with Lagos State Emergency Management Agency (LASEMA) and Lagos State Waterways Authority (LASWA) playing an important role. Other agencies included; NCAA, NAMA, Nigerian Police, Nigerian Air Force, Marine Navy-International Maritime Organization/International Transport Fund (IMO/ITF), Nigerian Army, Indigo Drilling, FRSC, Civil Defence corps, Bristow Helicopters, Nigerian Maritime Administration and Safety Agency (NIMASA), Department of Petroleum Resources (DPR), Kick Against Indiscipline (KAI), The Press, etc, gave necessary support. Julius Berger Nig. Ltd played a vital role in the wreckage recovery from the Lagoon.
NEMA initially sent the rescued passengers to Gbagada General Hospital and Afolabi Medical Centre for first aid while the deceased were deposited at the Mainland Hospital morgue. The six survivors were later transferred to St. Nicholas Hospital and they are responding to treatment.
The cause of the accident has not been fully determined, as the investigation is still ongoing. Meanwhile, interim safety actions have been taken by Federal Aviation Administration (FAA) and Sikorsky by the issuing of Emergency Airworthiness Directives (EAD) and Alert Service Bulletin (ASB) respectively on the Main and Tail Rotor Servo Input Rod assembly. This is to ensure the continued airworthiness and security of the assemblies. Bristow Helicopters Nig. Ltd. had earlier issued two Technical Directives as a safety action.
During the preliminary investigation AIB discovered that the Forward Main Servo Input Control Pushrod Assembly had failed. The Control Pushrod tube separated from Control rod end with the bearing and the Jamnut. The Jamnut was loose and was not seating against the Control Rod. See Figures 8 and 9.
National Transportation Safety Board (NTSB) Laboratory preliminary metallurgical examination of the Forward Main Rotor Servo Input Control Pushrod revealed that the separation was a pre-impact condition
Fig. 8 Control Pushrod and Control Rod end with bearing and Jamnut