MD83, vicinity Lagos Nigeria, 2012
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|On 3 June 2012, the crew of a Boeing MD-83 experienced problems in controlling the thrust from first one engine and then also the other which dramatically reduced the amount of thrust available. Eventually, when a few miles from destination Lagos, it became apparent that it would be impossible to reach the runway and the aircraft crashed in a residential district killing all 153 occupants and 6 people on the ground. The Investigation was unable to conclusively identify the cause of the engine malfunctions but attributed the accident outcome to the crew's failure to make a timely diversion to an alternative airport.|
|Actual or Potential
|Airworthiness, Fire Smoke and Fumes, Human Factors, Loss of Control|
|Aircraft||MCDONNELL DOUGLAS MD-83|
|Type of Flight||Public Transport (Passenger)|
|Origin||Abuja International Airport|
|Intended Destination||Lagos/Murtala Muhammed International Airport|
|Take off Commenced||Yes|
|ENR / APR|
|Location - Airport|
|Airport vicinity||Lagos/Murtala Muhammed International Airport|
|Tag(s)||Inadequate Airworthiness Procedures,|
Inadequate Aircraft Operator Procedures,
Ineffective Regulatory Oversight,
Root Cause Not Determined,
Deficient Crew Knowledge-handling
|Tag(s)||Post Crash Fire|
Inappropriate crew response - skills deficiency,
Inappropriate crew response (technical fault),
Plan Continuation Bias,
Procedural non compliance,
Ineffective Monitoring - PIC as PF
|Tag(s)||Loss of Engine Power,|
Flight Management Error
Delay in Declaration of Emergency
|System(s)||Engine - General,|
Engine Fuel and Control
|Contributor(s)||OEM Design fault,|
Component Fault after installation
|Damage or injury||Yes|
|Aircraft damage||Hull loss|
|Non-occupant casualties||Yes (6)|
|Fatalities||Most or all occupants (153)|
|Causal Factor Group(s)|
Air Traffic Management
On 3 June 2012, a Boeing MD-83 (5N-RAM) being operated by Dana Airlines on a scheduled domestic passenger flight from Abuja to Lagos as flight 992 successively lost power on both its engines, the first en route and the second on approach to Lagos in day VMC, after which the crew were unable to avoid the aircraft crashing into an urban area and it was destroyed by the effects of the impact and a post crash fire. All 153 occupants of the aircraft and 6 people on the ground were killed.
An Investigation was carried out by the Nigerian Accident Investigation Bureau (AIB). Both flight recorders were recovered from the wreckage in a badly burned condition. Data from the 30 minute CVR was successfully downloaded but it was found that the digital tape-based memory in the FDR had been destroyed by exposure to fire. A Preliminary Report detailing the initial findings of the Investigation was published on 5 September 2012.
It was established that both pilots were "foreigners" whose licences had been validated to allow them to work in Nigeria. The 55 year-old Captain was of American nationality and had 18,116 hours total flying experience which included 7,466 hours on DC-9 type aircraft. He had commenced employment with Dana Airlines less than 3 months prior to the accident and had been released for unsupervised flying a month prior to the accident. The 34 year-old First Officer was of Indian nationality and had 1,143 hours total flying experience which included 808 hours on type, his first experience of a commercial jet aircraft. He had been appointed as a pilot by Dana Airlines in 2011 after serving as their Director of Cabin Service.
It was established that twenty minutes after take-off from Abuja, Lagos ACC had been advised that the aircraft was cruising at FL260 and estimating Lagos in a little less than half an hour. Just prior to this point, the recovered CVR recording had started. When it did, the pilots were in discussion about "a non-normal condition regarding the correlation between the engine throttle setting and an engine power indication" although there was no suggestion that this condition would affect the continuation of the intended flight. It was apparent that the First Officer was acting as PF at this stage.
The flight crew continued to monitor the condition and "became increasingly concerned" as the aircraft commenced and continued its descent into Lagos. A report passing 18,100 feet was made 14 minutes before the crash occurred and one passing 7,700 feet ten minutes later by which time the aircraft had already been vectored onto the ILS LOC for runway 18R. At about 3,500 feet the crew were recorded as observing that there was now no response to movement of the left engine thrust lever either and the Captain took over as PF.
For the next ten minutes or so, it seems that there was nothing of note on the CVR recording except the execution of pre landing tasks including the deployment of the flaps/slats and the selection of the landing gear down after which the First Officer enquired "both engines coming up?" to which the Captain's response was "negative". After a brief discussion prompted by the First Officer, it was "agreed to declare an emergency" which was done indicating "dual engine failure, negative response from throttles". After requesting the crew to 'say again' the controller then instructed the crew to change to TWR. The First Officer called the Purser on the crew interphone and informed them "to prepare for landing and that, as of then the situation appeared under control". A further stage of flap was then selected and the possibility of landing on runway 18L instead was discussed after which the Captain reported having the runway in sight and "instructed the First Officer to raise the flaps and select the landing gear up" in an attempt to extend range in the absence of thrust. With about a minute to go until ground impact, it was apparent that the crew had again attempted to recover engine power without use of any corresponding checklists. The crew did not check in with TWR and the Investigation concluded that the instruction to change frequency was an inappropriate response to an aircraft which had just declared an emergency.
Shortly afterwards, the aircraft crashed on the densely populated residential area of Iju-Ishaga which lies on the extended centreline of runway 18R just under 6 nm from the airport and a huge post crash fire began almost immediately, rapidly consuming "about 85%" of the distributed wreckage of the aircraft.
The Investigation noted that although the airline had an approved Operations Manual (OM), it was clear from the available evidence that the crew had not paid much attention to it even to the extent of a call for a checklist not resulting in it being read. In particular, the QRH procedures for loss of engines which required to land at the nearest suitable airport were ignored - with Ilorin, Akure and Ibadan all overflown en route to Lagos. It was noted from the CVR data that at one point, the Captain had "asserted that the aircraft could not quit on them" and later said that declaring an emergency would make Nigerian CAA "come after them" suggesting that the delayed declaration of emergency had been "due to unexplained fear of the Regulatory Body". The authority gradient in the flight deck was also noted to have evidently been high with the First Officer finding it difficult to be assertive with a negative effect on CRM. The First Officer had made some good suggestions such as delaying the descent which would have presented the crew with more options when the second engine lost power. It was also noted that it was the First Officer who suggested that it was time to declare an emergency.
As well as much deviation from OM procedures, inappropriate tactical decision making had been demonstrated too - one of the over-flown airports, Ilorin, was the FPL destination alternate and the Captain's calls for landing gear and flaps during the approach even when it was becoming clear that any restoration of engine power was increasingly unlikely were soon reversed.
The Investigation also identified a number of concerns about the recruitment of the Captain and his release to unsupervised command, many of which appeared to call his competence into question. Some of these were directly related to the regulatory process for validating a foreign pilot licence for use when flying for a Nigerian operator.
The Investigation conducted a simulation of the accident flight which established that the accident could have been avoided or at worst the casualties minimised. All the simulated solutions tested were "within the limits of the aircraft performance and safe operations". It was concluded that the difference between them and what happened was the "aggravating factors" of "lack of situation awareness, inappropriate decision making and poor airmanship".
Finally, notwithstanding the lack of FDR data, extensive attempts were made to try and establish what had caused the apparent inability to control the engine outputs with the thrust levers. No conclusive evidence of cause could be found but with no evidence that engine flameout had occurred, one of the accident aircraft engines was found not to have been modified to address a known and historic material fatigue related fuel feed problem with some variants of the engine type involved - the Pratt & Whitney JT8D. This fault had in the past led to engine thrust control problems similar to those which appeared to have occurred during the accident flight and the solution had been to implement Pratt & Whitney SB 6452 (2003) which required replacing or modifying the left and right secondary fuel manifold assemblies. It was found that an unmodified engine on another Dana Airlines MD83 aircraft had, during the course of the Investigation, led to an air turn back due to similar symptoms to the ones which appeared to have occurred on the accident flight. Like the two engines recovered from the accident aircraft wreckage, the engine had damage to the fuel manifolds and their fittings which in this case could be linked to incorrect component installation. Since in this case, it had been found that one part of the fuel manifold system had been improperly installed and that all three engines had been recently overhauled by the MRO, it was suspected that this could have happened on one or both of the accident aircraft engines and concluded that an improved maintenance procedure to minimise the chances of incorrect installation was required.
Three Probable Causal Factors in respect of the accident were formally documented as follows:
- Engine number 1 lost power seventeen minutes into the flight and thereafter, on final approach, engine number 2 lost power and failed to respond to throttle movement on demand for increased power to sustain the aircraft in its flight configuration.
- The inappropriate omission of the use of the Checklist, and the crew’s inability to appreciate the severity of the power-related problem, and their subsequent failure to land at the nearest suitable airfield.
- Lack of situation awareness, inappropriate decision making, and poor airmanship.
A total of 8 Safety Recommendations were made as a result of the Investigation. In the Preliminary Report published on 5 September 2012, 4 Interim Safety Recommendations were made as follows:
- that Dana Airlines should ensure that prior to resumption of flights, visual fuel tanks inspection for evidence of fungal growth or contamination followed by biocide treatment be carried out in all operating MD-83 aircraft. The fungicide additives used in the fuel must be approved by aircraft and engine manufacturers. The frequency of treatment and the dilutions prescribed by the aircraft and engine manufacturers must be adhered to. The aircraft maintenance schedule or programme should be amended to include the exercise in accordance with the aircraft and engine manufacturers’ requirement. [2013-001]
- that Dana Airlines should ensure that for all its flight operations with MD-83, a minimum of 2000lbs of fuel must be maintained in the centre fuel tank of the aircraft on landing at any destination, while AIB investigation goes on. [2013-002]
- that Dana Airlines should ensure that:
- an adequate background check is conducted (prior to) the employment of foreign airline Captains and (other) safety critical employees. Such checks should include review of cases of revocation, withdrawal and suspension of licences by regulatory bodies in the applicant’s current or historical employment records where applicable.
- any newly employed foreign Captain must fly with a competent Senior First Officer who is familiar with Nigerian Airspace and routes for at least the first 100 flight hours, to enable the new Captain to be conversant with the operations of the airlines within Nigerian Airspace. [2013-003]
- that the Nigerian CAA should:
- as an essential aspect of its oversight function review CPL / ATPL / issue / renewal / validation forms to include a background check with a view to discover cases of revocation, withdrawal or suspension of flight crew licences issued to applicants by any other regulatory authority.
- Validate foreign licences only after all confidential details have been received from previous employers and appropriate regulatory authority including satisfactory aero-medical reports and a return of due diligence form/document carried out by the airline.
- include an appropriate declaration which obliges (licence validation) applicants to declare all relevant information as requested in the questionnaire/form. [2013-004]
At the conclusion of the Investigation, a further 4 Safety Recommendations were made as follows:
- that the FAA should ensure that Pratt & Whitney considers the following:
- The revision of Service Bulletin JT8D 6452 making it mandatory within a given time-frame, thereby upgrading the Compliance Category.
- The re-design of the installation and shimming procedures used in engine manifold assembly so as to remain foolproof to prevent incorrect installations. [2015-001]
- that Dana Airlines should ensure that:
- Any remarks or deviations from Company Standard Procedures noted by the Training Captain conducting Trainee Line Training must be addressed before final checkout as a Line Captain.
- All training procedures are in compliance with the approved Company
Operations Manual, SOPs and Nigerian Civil Aviation Regulations. [2015-002]
- that the Nigerian CAA should:
- closely monitor the work processes, ethics and conduct of foreign Maintenance Repair and Overhaul (MRO) facilities approved to overhaul and repair Nigerian-registered aircraft, airframes, powerplants, propellers or equipment.
- ensure that oversight of foreign MROs includes, but is not limited to, a review of track records, reputation and audit reports by the appropriate national regulatory authority before the approval or renewal of a Nigerian CAA authorisation occurs.
- ensure that for any checkout of a new line Captain, a type-rated Nigerian CAA Inspector must be involved as an observer. [2015-003]
- that the Nigeria Airspace Management Agency (NAMA) Quality Assurance Management (QAM) process should ensure that all Air Traffic Controllers strictly adhere to the ethics of their profession which includes providing assistance to flight crew in emergency/critical situations. [2015-004]
The Final Report was published on 13 March 2017.