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Date: | Thursday 3 January 2019 |
Time: | 10:55 |
Type: | Boeing 737-5L9 |
Owner/operator: | Azman Air |
Registration: | 5N-AIS |
MSN: | 29235/3076 |
Year of manufacture: | 1998 |
Total airframe hrs: | 34675 hours |
Fatalities: | Fatalities: 0 / Occupants: 114 |
Other fatalities: | 0 |
Aircraft damage: | None |
Category: | Serious incident |
Location: | near Port Harcourt -
Nigeria
|
Phase: | Approach |
Nature: | Passenger - Scheduled |
Departure airport: | Lagos-Murtala Muhammed International Airport (LOS/DNMM) |
Destination airport: | Port Harcourt Airport (PHC/DNPO) |
Investigating agency: | AIB Nigeria |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:On January 3, 2019, at about 10:10 h, an Azman flight AZM 2316 departed Lagos for Port Harcourt in Nigeria. on an Instrument Flight Rule (IFR) Flight Plan with 109 passengers and five crew on board. The flight was the first flight of the day for the aircraft. There was no reported technical fault or observation on both engines during the previous flight.
The take-off and climb out phase was normal. The captain was the Pilot Flying (PF) and co-pilot was the Pilot Monitoring (PM). The aircraft levelled off at a cruising altitude of 29,000 ft (FL290). According to the Flight Data Recorder (FDR), Engines No. 1 and No. 2 were both showing 84.6% N1.
According to the flight crew, at some point during the cruise, about 20-25 minutes into the flight, they heard a loud bang which lasted for about 4-5 seconds followed by a yaw to the right. At about 10:28 FDR data revealed that the engine no. 2 N1 value started decreasing for about 4.3 seconds (which corresponds to the point at which the crew heard a bang and experienced a yaw).
The flight crew also stated that engine parameters look normal at that time and in addition, the purser reported that there was nothing unusual noticed in the cabin after the loud bang. The flight crew, therefore, assumed that the bang was associated with a cargo shift. The aircraft was on Autopilot (A/P) and Auto Throttle (A/T).
At about 10:42, Port Harcourt Approach cleared the aircraft for a straight in approach on runway 21; Flap 15° was selected, Localizer captured, Glideslope captured and the gears were selected DOWN. As the A/P disengaged, the aircraft suddenly yawed to the right accompanied by severe vibration and also thrust asymmetry was noticed. At that time, the aircraft was two dots below the glide slope and the field was not in sight. The PM noticed no.1 engine vibration indicating 3.0 to 3.5 units. No.1 engine N1 was 65%, no.2 engine N1 was 35% and the no.2 Oil Filter Bypass Light came ON. This led to precautionary shut down of no. 2 Engine by the crew.
FDR data also indicated that, at one point before the approach, the figure of engine instruments were indicating almost the same with no difference until about 10:53 h when the crew advanced the throttles individually in order to verify the engine outputs. At that time, the crew noticed that no. 2 engine did not respond appropriately to the throttle movement. FDR data also indicated that no. 2 engine was shut down five minutes after the verification of the engine output.
In order to figure out what was happening, the captain handed over control to the co-pilot. The crew accomplished the Severe Engine/Damage Checklist. However, the first approach became unstable and the crew executed a missed approach at about 10:55 h.
At about 11:09, when the ATC cleared the crew for the second approach, the response was that they were not ready for the approach at that moment. However, they requested for vectors as they were having a problem with no. 2 engine.
During the second approach to runway 21, the aircraft came high on the approach and was off track of the runway centreline. At about 11:19, the crew declared an emergency and executed a second missed approach. However, the crew were able to land the aircraft safely on runway 21 after the third approach at about 11:35.
Causal factor
The failure of number 4 and 5 bearings of engine number 2 leading to loss of power during approach.
Contributory factors
1. The failure to recognise the abnormal engine conditions (surge) during cruise phase and hence, not making appropriate decision. This might have been connected to the insufficient technical knowledge and loss of situational
awareness.
2. Non implementation of the Flight Data Monitoring programme in accordance with 2.2.5.1 of Azman Air Safety Management System Manual.
3. Non rectification of the number two engine vibration anomalies recorded over a period of 8 months.
4. Inadequate regulatory oversight of the Azman Air Safety Management System.
Accident investigation:
|
| |
Investigating agency: | AIB Nigeria |
Report number: | AASL/2019/01/03/F |
Status: | Investigation completed |
Duration: | 3 years and 4 months |
Download report: | Final report |
|
Sources:
http://www.aib.gov.ng/media/1195/preliminary-report-on-azman-5n-ais.pdf Revision history:
Date/time | Contributor | Updates |
06-Feb-2019 20:42 |
harro |
Added |
06-Feb-2019 20:44 |
harro |
Updated [Damage] |
21-May-2024 06:36 |
ASN |
Updated [Narrative, Accident report] |
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