Impact of emergency corrosion checks on all Boeing airplanes in Nigeria, by Kyari

Aircraft engineer, Sheri Kyayi has expressed concern over the grounding of all B737 aircraft types that are scheduled to undergo the United States Federal Aviation Administration (FAA) emergency corrosion checks.

The situation may not have adverse effects on the airlines using Boeing aircraft types as many of the aircraft are still in storage because of the very low passenger traffic that has made carriers to operate what can best be described as skeletal services.

This could also put huge additional costs to the carriers that are struggling to bounce back to service after almost month hiatus.

While lauding the need for operators to subject their equipment to thorough checks as directed by the Nigerian Civil Aviation Authority (NCAA), he noted that if the airplanes do not pass the test, they would have to order for the valves from overseas while their aircraft will be on the ground.

He pointed out that with the situation, only Ibom Air with CRJ aircraft, Overland Airways and few others with other aircraft types will be flying since they don’t operate that aircraft type.

His words, “This is an Airworthiness Directive (AD). It means that on receipt, all B737 will automatically be grounded and cannot be in the air till the inspections are done and aircraft cleared of the suspected snags”.

“There is work for the airlines this week but because of our environment, inspections to be carried out may have most engines passing the required inspections. If they don’t the inspections, it will be an issue for many because some will have to order for these valves from overseas while their aircraft will be on ground. Ibom Air and a few will be flying since they don’t operate such make”.

Nigerian scheduled airlines have about 65 airplanes, majority of them made up of B737 classics and few B737NG.

The breakdown shows that Dana has nine aircraft including recently acquired B737; Arik Air operates seven B737; Aero has five, but two are undergoing maintenance

Air Peace is reported to have about 24 aircraft. Majority of the aircraft in its fleet are B737-400, B737-500; B777 and other narrow body airplanes.

Max Air has six airplanes made up of three B737 and three B747 while Azman Air has three aircraft including A340.

It would be recalled that the Nigerian Airspace Management Agency (NCAA) has asked all operators of B737 aircraft type to subject their airplanes which have been in storage for a long time to the Federal Aviation Administration (FAA) emergency corrosion checks.

This is contained in a letter dated July 24^th, 2020 and addressed to all Boeing 737 aircraft operators and signed by General Manager, AOC & S, Engr. G.G. Balang for the Director General.

The letter with subject, “FAA Emergency Airworthiness Directive (AD) 202016-15 sent to owners and operators of the Boeing Company Model 737-300, -400, -500, -600, -700, -700C, -800, -900, and -900ER series planes.

According to Balang, the emergency AD was prompted by four recent reports of single-engine shutdowns due to engine bleed air 5^th stage valves being stuck open.

He further stated that, “corrosion of the engine bleed air 5^th stage check valve internal parts during airplane storage may cause the valve to stick in the open position”, stressing that if this valve opens normally at take-off power, it may become stuck in the open position during flight and fail to close when power is reduced at top of descent, resulting in an unrecoverable compressor stall and the inability to restart the engine.

Corrosion of these valves on both engines according to him could result in compressor stalls  and dual-engine power loss without the ability to restart, which could result in forced off-airport landing.

He further explained that the authority had reviewed the FAA AD2020-16-15 vis a vis the COVID-19 pandemic lockdown that necessitated the storage of B737 aircraft and made a determination that compliance with the FAA emergency AD must be carried out by affected operators of Boeing 737 aircraft in Nigeria as required by the AD.

He equally stated that all affected operators should submit evidence of compliance with the FAA AD2020-16-15 to their Principal Maintenance Inspector (PMI) within two days following compliance.

The FAA, it would be recalled the AD because the agency evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Wole Shadare