The Accident Investigation Bureau (AIB) yesterday released the report of four air accidents. They include: Bristow Helicopters, Registration 5N-BMM at Port Harcourt International Airport, River State on July 14, 2011; Aero Contractors Nigeria Limited Boeing 737-500 Registration 5N-BLE at Runway 28 of the Yakubu Gowon Airport, Jos, Plateau State on August 21, 2010; OAS, Registration 5N – BHU, en route Delta Steel Company, Ovwian, Aladja, (Near Osubi Airstrip), Warri, Delta State which occurred on November 10, 2006 and Wings Aviation Limited aircraft which crashed in mountainous terrain at Bushi Village, Obalinku Local Government Area of Cross River State. Excerpts from the reports:
The Accident Investigation Bureau (AIB) was notified of the accident in the evening of 14th July 2011, investigators were dispatched and arrived at the site in the morning of the 15th July 2011. All the relevant authorities were informed, but no accredited representative participated in the investigation. The investigation was conducted by the Bureau in accordance with the provisions of the Civil Aviation Act 2006 and ICAO Annex 13.
5N-BMM departed Lagos at 1856 hrs for Port Harcourt on an Instrument Flight Rules (IFR) and estimated Port Harcourt at 1940 hrs. The aircraft was cleared to maintain FL 330.
The aircraft made first contact with Port Harcourt at 1914hrs. The pilot reported maintaining FL330 with six souls onboard, four hours fuel endurance and estimating POT VOR at 1940hrs.
At 1921hrs, the pilot reported 100 NM to POT and requested for descent. The aircraft was cleared for descent through different levels and finally cleared for the straight-in ILS Approach Runway 21 and to report on the localiser.
On final approach, the crew were no longer visual but continued the approach, crash landed and exited the runway.
The investigation identified the following:
Causal factor: The decision of the pilot to continue the approach without the required visual references.
Contributory factors:
• Poor crew co-ordination. (CRM)
• Pairing two captains together.
• The weather was marginal.
History of flight
5N-BMM departed Lagos at 1856hrs for Port Harcourt on an Instrument Flight Rules (IFR) and estimated Port Harcourt at 1940 hrs. The aircraft was cleared to maintain FL 330.
The aircraft’s first contact with Port Harcourt was at 1914hrs. The pilot reported maintaining FL330 with six souls onboard, four hours fuel endurance and estimating POT VOR at 1940hrs. The aircraft was cleared to POT, to maintain FL330 with no delay expected for ILS Approach Runway 21, QNH 1011 and to report when released by Lagos. At 1921 hrs the pilot reported 100 NM to POT and requested for descent.
The aircraft was cleared to descend to FL150. At 1927hrs the pilot requested for further descent and was cleared to 3,300ft on QNH. 1011 but the pilot acknowledged 3500ft. At 1931hrs the aircraft was re-cleared to FL 090 initially due to departing traffic on Runway 03.
At 1934hrs 5N-BMM reported maintaining FL090 and was re-cleared to FL050. The aircraft was re-cleared to 2000ft on QNH 1011 at 1936hrs and cleared for the straight-in ILS Approach Runway 21 and to report on the localiser. At 1947hrs, the pilot reported final for Runway 21 and was asked to contact Tower on 119.2 and the Tower asked 5N-BMM to report on glide slope Runway 21. At 1950hrs, the Tower asked 5N-BMM to confirm on the glide slope and the crew confirmed “Charlie, we have three miles to run”. The Tower cleared 5N-BMM to land with surface wind calm but to exercise caution since the Runway surface was wet and 5N-BMM responded “wind calm”. At 1952:26hrs, the auto voice callout “minimums minimums” alerted the crew. At 1952:40hrs, the pilot flying (PF) said “I am not on the centerline”. At 1952:48hrs, he said “I can’t see down”.
At 1952:55hrs, the pilot monitoring (PM) said to the pilot flying: “ I am telling you to go down” and the pilot flying said: “ I will go down”, five seconds later the aircraft crashed. The crew exited the aircraft without accomplishing the Emergency Evacuation Checklist and therefore left the right engine running for about 28 minutes after the crash. The Fire Service eventually used their water hose to shutdown the running engine.
At 19:54hrs, the Tower called 5N-BMM to pass on the landing time as 19:53hrs, but no response from 5N-BMM. There was no indication that the aircraft was taxing on the runway because it was dark and no light was visible hence the need to alert the fire personnel. The watch room was asked to give the Tower information, which they could not give since they do not have a two – way contact with the fire trucks.
The Tower could not raise the fire truck since there was no two-way communication between them. However, the fire truck was later cleared to proceed to the runway as the Tower could not ascertain the position of the aircraft.
The aircraft was actually turned 90o because of the big culvert that held the right wing and made the aircraft spin and turned 90o facing the runway, two metres from the active runway, the culvert was uprooted due to the aircraft impact forces. The wheel broke off because of the gully that runs parallel to the runway.
Aero Contractors’
Boeing 737-500
Accident Investigation Bureau (AIB) was notified of the serious incident on the same day 21st of August, 2010 and investigators arrived in Jos in the morning of the next day 22nd of August, 2010. All other stakeholders were notified.
On 21st of August, 2010, about 1738 hrs, Aero Contractors flight 210, a Boeing 737-500, 5N-BLE, skidded off the threshold of runway 28 while landing on approach into Yakubu Gowon Airport, Jos, Plateau State. The flight was operating under the provisions of NCAA regulations as a scheduled domestic passenger flight from LOS to Yakubu Gowon Airport, Jos. The flight departed LOS about 1627 hrs, with two pilots, three flight attendants, and 87 passengers on board. The airplane commenced an approach and touched down with the Right Main Wheel 135 metres from the threshold, skidded off the runway 28 to the left into the grass area, damaged three runway light assemblies and uprooted the armored cables at the airport. All 92 persons on board sustained little or no injury, and the aircraft was substantially damaged. The airplane was operated on an instrument meteorological condition (IMC) flight plan. The incident happened at about 1738 hours.
The investigation identified the following causal and contributory factors.
Casual factor:The decision of the crew to continue the approach in an unstabilised condition, coupled with the Captain in-appropriate attempt to take over control of the aircraft.
Contributory factors:
•Fatigue, which impaired the Captain’s performance and reflected the effects of a long, demanding duty day associated with check airman functions.
• Poor Crew Resource Management.
• The prevailing weather condition.
Two safety recommendations were made.
OAS crash in Delta
The accident involving 5N-BHU belonging to OAS Helicopters was reported to the erstwhile Accident Investigation and Prevention Bureau (AIPB) on 10th November 2006. All relevant authorities were notified. The investigation into the accident began on the 11th November 2006.
The aircraft 5N-BHU (Helicopter) was conveying the MD/CEO and other staff of the company for a business meeting in Port Harcourt. It departed Lagos at 0713hrs under Special Visual Flight Rules (Special VFR) while maintaining 500 ft.
The aircraft could not continue the flight to Port Harcourt and was returning to Osubi airstrip due to bad weather. At 0904hrs, the Pilot could not give his position when requested by the Air Traffic Controller and collided with high tension cables belonging to Power Holding Company of Nigeria (PHCN) located along the road to Delta Steel Company, Ovwian, Aladja, Delta State. Three survivors were evacuated from the wreckage while the fourth person was found fatally injured outside the aircraft. One of the three survivors later died in the hospital.
The investigation identified the following.
Casual factor:
The pilot’s decision to conduct the flight under a Special Visual Flight Rule (SVFR) in an Instrument Meteorological Conditions (IMC) as depicted by the weather forecast.
Contributory factors:
• The pilot’s descent from 500ft without a clear visual reference.
• The pilot was not instrument rated.
Four safety recommendations were made.
History of the flight
The helicopter which was owned and operated by OAS Helicopters departed Lagos at 0713hrs under Special VFR enroute Port Harcourt with four persons on board. The Helicopter was conveying the Managing Director/CEO and some staff of the Company for a business meeting at Port Harcourt. The aircraft was maintaining 500ft when the Pilot contacted Osubi airstrip at 0823hrs. The Controller passed the QNH 1012 hPa to the aircraft and to report when abeam Osubi airstrip.
At 0831hrs, the pilot called the controller and requested weather over the station and the following weather information was passed to the aircraft, which the pilot acknowledged.
At 0834hrs, the aircraft reported abeam Osubi and the controller asked the pilot to report when crossing River Niger at Patani. At 0854hrs, the pilot called Osubi Tower that he was returning to the airstrip due to en route bad weather. He gave a time of 6 minutes to the airstrip and an altitude of 200ft; but when the controller asked the pilot to confirm his altitude, the pilot confirmed maintaining 500ft.
At 0904hrs, the controller called the pilot and requested his position. The pilot acknowledged the call but could not give his position again.
Series of calls were then made by the controller and other aircraft belonging to Bristow Helicopters and Aero Contractors Nigeria Limited flying in the area to re-establish contact with the aircraft but there was no response.
At 0909hrs, there was a telephone call from an eyewitness informing the Tower that a helicopter had crashed along the road to Delta Steel Company, Ovwian, Aladja, Delta State. The Osubi airstrip fire service moved to the site, which was about 10km Southeast of the field. The initial rescue operation was carried out by eyewitnesses and passersby. Three persons were evacuated from the wreckage while the fourth person was fatally injured and found outside the aircraft. One of the three survivors later died in the hospital.
Wings Aviation Limited crash in Obalinku
The Accident Investigation Bureau (AIB) was notified of the missing aircraft at about 1400 Hrs on 15th March, 2008 whilst the search and rescue exercise had commenced. AIB monitored the progress of search and rescue and later joined as an observer on the 17th March, 2008.
This was to facilitate the process of accident investigation after the wreckage of the missing aircraft would be found or the search and rescue officially called off.
On 15th March, 2008, about 0920 hours, 5N-JAH, Beech 1900D, operated by Wings Aviation Limited as flight TWD 8300, on a revenue positioning flight, crashed in mountainous terrain at Bushi Village, Obalinku Local Government Area of Cross River State. Instrument Meteorological Conditions prevailed at the time of the accident. The aircraft was on an instrument flight plan. The flight originated at Murtala Muhammed
Airport (MMA), Lagos, Lagos State and the destination was Bebi Airstrip (DNBB), Obudu, Cross River State.
According to Air Traffic Service, an instrument flight plan was filed with a routing indicating departure from DNMM to Bebi, via Lagos VOR, Potgo Intersection, Enugu VOR at an altitude of 25,000 feet AMSL. The estimated departure and arrival times were respectively 0736 and 0921 hrs.
The aircraft departed MMA at 0736 hrs as per the filed flight plan climbing to FL250 (twentyfive thousand feet) estimating Potgo at 0836 hrs and Bebi at 0921 hrs. It was transferred to Portharcourt Tower at 0845 hrs and released to Enugu Tower at 0856 hrs descending to FL110 (eleven thousand feet).
While passing FL160 (sixteen thousand feet), it requested for further descent and was cleared by Enugu Tower to descend to FL050 (five thousand feet).
The aircraft deviated from the filed flight plan route, and flew through the airway (UA609) direct to Ikrop, instead of Potgo-Enugu and Bebi direct. The inputs into Global Positioning System (GPS) gave the crew different distances to Bebi. The crew agreed on a coordinate to input and thereafter were busy trying to locate the airstrip physically.
During this process, the Ground Proximity Warning System (GPWS), gave signals and sound of “Terrain, terrain….pull up, pull up” several times without any of the pilots following the command. The aircraft flew into the terrain and crashed. The flight crew and passenger were fatally injured.
The airplane was destroyed and there was post-crash fire. The FDR shows that the aircraft crashed at about 0920:15 hrs at an altitude of about 3,400ft. According to the FDR analysis, the aircraft flew for 103.75 minutes before impact.
At 0939 hrs, the Obudu Radio Operator reported to Bebi Airstrip Police Post, Obudu Fire Service, one hour later and Sankwala Police division at 1000 hrs. He further contacted Lagos at 1157 hrs; and finally contacted Director of Skynote at 1213 hrs.
Search and rescue exercise by NEMA commenced approximately two hours later at 1400 hrs. Bristow Helicopters Ltd joined the SAR team later same day.
Search and rescue operations commenced on Saturday, 15th March, 2008 and continued till Friday 21st March 2008, within which the following operators joined with their aircraft:
Bristow Helicopters Ltd, Caverton Helicopters, Aero Contractors Ltd and Border Patrol.
Accident Investigation Bureau monitored the rescue effort on the 15th and 16th March, 2008, before joining the search team at the Rescue Control Centre (RCC), Calabar, on the 17th March, 2008.
The six-day SAR activity covered more than 11 local government areas in Cross River, Benue and Enugu states.
The investigation identified the following causal and contributory factors:
Causal factors:
•The flight crew conducted an approach into a VFR airfield in an instrument meteorological condition and did not maintain terrain clearance and minimum safe altitude which lead to controlled flight into terrain.
• The crew did not respond promptly to GPWS warning.
Contributory factors:
•The flight crew was not familiar with the route in a situation of low clouds, poor visibility and mountainous terrain.
• The area controllers did not detect the estimates as passed by the pilot for positions not in the filed flight plan (LIPAR and LUNDO) and omitting ENUGU.
• The erroneous co-location of Bebi airstrip and Obudu on the NAMA chart confused the crew.