5N-BQJ, Sikorsky S-76C++ aircraft, a domestic chartered flight operated by Bristow Helicopters Nigeria Limited, departed Lagos on the 3rd of February 2016, for ERHA FPSO (Floating Production Storage Off-loading). Instrument meteorological conditions prevailed at the time and Instrument Flight Rule (IFR) flight plan was filed. Two flight crew members and nine passengers were on the outbound trip that was almost uneventful. The captain was in command as the pilot flying (PF), upon landing in ERHA (Off Shore Platform location) a passenger onboard seated in the middle row complained about perceiving a burning smell; although, the flight crew did not perceive any smell.
The PF had a word with the passenger and went back to check the internal and external of the aircraft for smell, the check result was negative. However, the crew reported that Digital Auto Flight Control System (DAFCS) and TRIM FAIL lights illuminated twice and were reset on the outboard leg to ERHA FPSO.
5N-BQJ departed ERHA for the inbound trip to Lagos at 09:50:00hrs with nine passengers and was flying at 3000ft with the co-pilot as the pilot flying (PF) and the captain as the pilot monitoring (PM). The captain asserted that within 15 minutes after departure, that “we got repeated illumination of the „TRIM FAIL‟ and „DAFCS‟. The Emergency Operational Procedure (EOP) was consulted and the pilot flying was advised to fly hands and feet on the controls, which he did”. Initial contact was established at 75NM with Lagos Approach. The PF called my attention to the collective being heavy and the power dropping anytime he pulled to maintain power. I noticed a slight turn to the right and I called the PF to check his heading and almost immediately he came back with a problem with the compass. I noticed a fast spinning of the Electronic Horizontal Situation Indicator (EHSI) and compass, the instrument readings inaccurate/inconsistent, the aircraft started a turn to the right with a high rate of
descent.” The captain further said “I remembered taking the controls from the PF. I noticed the controls not responding properly, I made a distressed call on the Approach
frequency. We stabilized at 1500ft”.
According to Air Traffic Controller‟s transcript, the flight first contact and the first clearance with Lagos Approach were at 10:04:37hrs which stated “5N-BQJ is cleared to the field not above three thousand expect visual approach for runway 18L report for descent”.
While the Lagos Approach efforts in trying to raise 5N-BQJ were abortive, an aircraft 5N-MPN agreed to help relay between the Approach and 5N-BQJ. At 10:09:13hrs 5N-MPN relayed “Lagos standby they are calling that they stabilized on a thousand five hundred. Just standby”. At 10:09:44hrs 5N-MPN relayed “Okay they lost all their instruments. Aircraft stabilized at a thousand five hundred on the radial 143 65NM proceeding back to Lagos I believe”.
At 10:16:22hrs, Lagos Approach asked another aircraft AZM 2322 to help raise 5N-BQJ stating “Please can you help me raise 5N-BQJ a helicopter from ERHA declared MAYDAY shortly to know his intention, estimates to LAG or he‟s going back to ERHA?” The Captain stated that “I noticed the cyclic not responding to lateral movement. I updated the MAYDAY call on Lagos Approach frequency and declared a MAYDAY on ERHA frequency”. The complaint from the crew that the aircraft was not responding to control inputs was relayed by two aircraft. AZM 2322 followed the communication until the aircraft ditched.
At 10:17:58hrs AZM 2322 relayed to Lagos that “They are ditching the aircraft Lagos. They are declaring an emergency they are ditching the aircraft. They have thirteen souls on board. They are ditching. Position is 136 75 miles. It‟s an emergency”. The souls onboard was confirmed eleven later. Other aircraft joined in the search and rescue, no visual contact was reported by Caverton Company aircraft at 10:36:44hrs. At 10:38:49hrs, Approach reported “Copied still negative contact with the other aircraft on 78NM radial 138 confirm?”
However, the aircraft ditched safely at about 10:25:00hrs into the Atlantic Ocean at about 75NM to Lagos, the two life rafts were deployed, although the left raft was slightly damaged during jettisoning of the left side door. The passengers and crew safely evacuated into the life raft and were rescued one and half hours later. More passengers transferred to the right life raft, thus creating a tilt of the aircraft to the right. The aircraft later capsized with the Emergency floating devices holding the aircraft afloat upside down, fully submerged in the salty waters of the Atlantic Ocean at about 75NM to Lagos.