| Summary: | Approximately 16 months after the 5N-RAM accident, it was determined that loss of power of an engine was also experienced on 5N-SAI, an aircraft in Dana Airlines’ fleet. 5N-SAI MD-83, operating flight 0348 Port Harcourt to Lagos, suffered loss of power on No.1 Engine during climb out at 14,000ft. The Engine failed to respond to throttle movement and remained at idle power 1.03 EPR. That incident led to an air return on 6th October, 2013 for which the Airline issued an Engineering Authorization No. MD83-EA-73-001. |
| Description of Dana MD-83 5N-SAI Air Return Incident | On the other aircraft 5N-SAI that made an air return on 6th October, 2013, the shop and teardown investigation showed the same characteristics as the engines on DANACO 0992 which had a fatal crash in Lagos.
In the course of the internal investigation carried out by the airline, the captain of the air return asserted emphatically that there were other aircraft in the Operator’s fleet that exhibited slow acceleration as in 5N-SAI. NCAA Audit of Dana Airlines of between 9th and 12th December, 2013 highlighted the need for Dana to propose corrective action on the directive that all the previously overhauled engines by Millennium MRO should be re-certified by an NCAA approved engine shop(s) before re-installation on Dana aircraft. The summary of the two problems is that they are common occurrences on the JT8D- 217C and 219 engines as acknowledged by Pratt & Whitney. As a result, the manufacturer in October, 2003 issued a Service Bulletin (SB) 6452 on the JT8D engines. Reason: 1. Problem: There have been several instances reported of secondary fuel manifold assembly fractures, causing fuel leaks, which resulted in 94 Unscheduled Engine Removals (UERs), one In-flight Shut Down (IFSD) and two Air Turn Backs (ATBs). There was also one contained fire in 2001 and the extent of the damage was confined to a dark streak of coked fuel on the Combustion Chamber Outer Case (CCOC), and fan duct damage. 2. Cause: Thermal expansion results in high stresses on the tubes, which do not have adequate fatigue life for those stresses. Also, installation of distorted manifolds and incorrect shimming of the manifold during installation can aggravate the condition. 3. Solution: Provide new secondary fuel manifold assemblies, incorporating tubes fabricated from new material which has a fatigue life that is approximately 2 times greater than the current tube material to improve the durability of the manifold assemblies. Description: Replace or modify the left and right secondary fuel manifold assemblies. The incident which led to the issuing of Engineering Authorization No. MD83-EA-73-001 dated 28/01/2013 is one in so many incidents that brought to the fore, failure of engine to respond to throttle movement. The following were the reasons and shop findings: Reasons: Following a recent incident involving an air return for an engine failing to respond to throttle movement, the engine was subsequently removed for shop investigation after inspection and troubleshooting revealed un-burnt fuel escaping in the fan duct section of the engine during ground run. Shop findings indicate that one of the two fuel manifolds enclosing primary and secondary fuel supply lines in the fan air discharge section located approximately at 5 o’clock position was found not to be of standard configuration, with the secondary supply line severed. The investigation revealed that the improper installation of the manifold assembly resulted in high velocity bypass fan air stressing of the assembly due to its not being aerodynamically sealed. The engine manufacturer knew that the problem existed and thus issued SB 6452 with compliance code ‘6’ to take care of the problems. An Alert Service Bulletin would have been more appropriate since it makes the modification urgent and timely with higher level compliance category. Making the installation to fit only in one direction will eliminate the issue of incorrect shimming of the manifold during installation, which the manufacturer opined aggravates the condition. |
| Details | Details are contained in the following document, and specific sections:
https://aib.gov.ng/wp-content/uploads/2019/09/dana-airlines-md83-5n-ram.pdf
|