Jet fuel contamination, risk to air safety

Jet fuel contamination has led to many unfortunate incidents in the past in many parts of the world including Nigeria. WOLE SHADARE writes that fuel contamination has become a recurring incident in the Nigerian aviation industry

Troubling times

Several troubling incidents of jet fuel contamination have prompted the Nigerian Civil Aviation Authority (NCAA) and other industry groups to pay close attention to the danger posed by bad jet fuel.

It’s no secret that jet fuel contamination can be extremely costly to aviation businesses. Aircraft engines may not fail right away when running on contaminated fuel. The first indications will likely be sputtering and a generally rough-running engine. Once enough water is mixed with fuel, combustion is no longer possible.

Nigerian airlines

Jet fuel contamination causes engine failure by damaging fuel system components and blocking the fuel supply to the engine. Once the fuel supply is cut off, fuel starvation occurs, which then leads to engine failure. Fuel starvation can also cause forced landing and Control Flight IntoTerrain (CFIT) accidents.

Water is the most common contaminant in aviation fuel. Because water it’s denser than 100LL, you’ll find water settling to the lowest part of the tank.

In fact, one instance of jet fuel contamination caused a commercial aircraft to be grounded indefinitely until the mystery of where a drum of water was found in the tank of Max Air is made known.

This grounding was a consequence of a probe into the reason for finding water inside the tank instead of jet fuel and this has had a huge financial impact on the airline.

Max Air jolts sector

Nigeria’s aviation industry was jolted last week with the ban of Max Air’s all B737 aircraft following the discovery of water in the fuel tank of one of the airline’s airplanes.

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The aviation regulatory body, the Nigeria Civil Aviation Authority (NCAA) quickly grounded the airline’s operations using the B737 aircraft type.

The Max Air aircraft was scheduled for Maiduguri but made a stop in Yola when the crew noticed that some parameters of the aircraft were not functioning well.

The source disclosed that the aircraft would have crashed had it proceeded to Maiduguri without the necessary check to observe what was happening.

The crew, it was gathered trouble-shoot the aircraft several times to restart but all to no avail.

After that, they tried to use the Auxiliary Power Unit (APU) to restart all to no avail: an indication that the engines of the plane were in preparation to shut down.

“It was through divine Providence that a major accident did not happen. Accidents do not just happen; it is a chain of events that cause air accidents. I have never in my life and as an aviator or aircraft engineer of over 25 years seen such quantum of water in the fuel tank of an aircraft,” a source close to the airline told our correspondent.

Again, there is unease over aircraft regulation of recent which has equally raised concern about airline operations, particularly MAX Air whose frequent safety infractions are well documented.

When contacted, the Director-General of Nigeria Safety Investigation Bureau (NSIB), Akin Olateru, an aircraft engineer confirmed that although the NCAA had commenced a proper investigation into what happened, he said his agency would equally look at the circumstances surrounding the incident.

Draw up standards, experts tell NCAA

Not a few had charged the aviation regulatory body to draw up standards for Jet-A1 quality assurance, starting with the transportation vehicles type or profile; supply and trucking systems; storage and dispensing systems.

They stated that at the moment, some vehicles supplying aviation fuel, otherwise known as Jet-A1 are not sufficiently distinct from those supplying other petroleum products.

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The consequence of all these development could result in fuel contamination as some of the former Accident Investigation Bureau (AIB) and now, the NSIB reports of some aircraft accidents have shown.

Ruptured pipelines

Up till about 1992, Jet-A1 supply to Murtala Muhammed Airport was through pipelines from Ejigbo or the Nigeria National Petroleum Corporation (NNPC) depot. The supply from the MMA depot to the hydrants on the apron where fuel is dispensed to aircraft, was done also through the pipelines. The method then was quality assurance in practice.

Unfortunately, since the pipelines got ruptured in 1992, nobody in NNPC, NCAA, Federal Airports Authority of Nigeria (FAAN) and even the airlines-the end users, raised serious concerns on why there had been no repairs of the pipelines in 31 years

The neglect of the repair of the pipelines is a major reason for the high cost of Jet-A1 and invariably the airline operating cost if the costs of transportation and demurrage on the tankers are considered.

These costs are huge and are substantial earnings for the owners of the tankers used for bridging the fuel supply between the NNPC depot and the airport depot, stressing that the tanker owners are those who would not want to see the pipelines repaired.

Posers

For now, nobody knows how water of that quantity got into the tank of the aircraft. Could it be an internal sabotage? Could it be that water found its way into the storage tanks of the fuel marketers? How come the airline did not test the fuel that was sold to it or have the mechanism to test the commodity it got?

There are so many conjectures here but all these would pale into insignificance until the aviation regulatory body or the NSIB make their findings known.

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For instance, water in aviation jet fuel can be detected in several different ways. The most common method is known as a water tablet test for fuel. This very briefly indicates whether the water in the fuel is above or below 30 ppm, the maximum allowed limit.

The accumulation of water is almost inevitable in stored aviation fuels even if it has a low water content at airport delivery because of a number of opportunities for moisture to be taken up. These include free water in low spots in a pipeline, rainwater leaking past the seals in floating-roof tanks, and moist outside air entering the vents of fixed-roof storage tanks.

Maintaining fuel quality

Once refined to specification and delivered as such to an on-airport storage facility, aviation fuel is drained on a daily basis to remove any water which may have resulted from condensation so as to minimise the chances of microbial proliferation.

Before being taken from bulk storage and uplifted by an aircraft, fuel is then filtered at least twice to ensure that it is free from particulate matter which could affect aircraft fuel systems, and to ensure that any remaining traces of free water are removed.

An aircraft re-fuels at an airport

Last line

Aviation fuel contamination is an event that one should never take lightly. Simple fuel contaminants such as particulate matter, microorganisms, and water, can have devastating effects on an aircraft’s airworthiness and often result in engine failure. If an engine were to fail mid-air, it would have catastrophic consequences for those on board.

Wole Shadare