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Almost 2 million road vehicles and just over 800 civil aircraft are registered in Lithuania. Although the numbers vary widely, regular inspection by experts is equally mandatory for both moving and flying vehicles.

The Transport Competence Agency (TKA) is responsible for civil aircraft registered in the country, which issues airworthiness certificates proving that the aircraft is safe to fly. Specialists of the institution carry out various types of aircraft inspections, which consist of two parts – the first is the inspection of documents and their records, and the second is a physical inspection of the aircraft to make sure that the condition corresponds to that indicated in the documents.

Vidmantas Plėta, head of the Aircraft Department of TKA, talks about the experience of general aviation aircraft inspections and the main reasons for refusing to issue an airworthiness certificate and thus grounding planes.

  1. All necessary maintenance work has not been performed.

“Each aircraft has flight and maintenance instructions – these specify the maintenance tasks that need to be carried out – some are annual and some are required when the aircraft has flown a specific number of hours. The nature of the work is indicated by the manufacturer himself, who, based on the available data, can predict the potential risks arising from intensive work of the aircraft.

When taking care of flight safety, it is necessary to familiarize yourself with these instructions and follow them, because if regular maintenance work is forgotten, problems may arise, which may later become not only more difficult to fix, but also lead to incidents or even accidents,” says the expert.

  1. At the end of the service life of the parts with a limited service life installed in the aircraft, or their working time is calculated incorrectly.

The operating and maintenance instructions of the aircraft also indicate the service life of some parts – that is, it is determined when and how often they should be replaced or overhauled.

“Details with a limited duration of operation include the engine, propeller, fuel and lubricant system hoses, control system elements. Some parts can be overhauled and some must be replaced. For example, most aircraft have an emergency radio beacon (ELT), which is activated in the event of an emergency to send signals to rescuers. No matter how actively the aircraft is used, its beacon battery is required to be replaced every 5 years so that it can do its job properly when needed.

Interestingly, the shelf life of a part begins immediately after it is manufactured or repaired, and not when it is installed on the aircraft. For example, fuel hoses that have been in storage for a couple of years and have a service life of six years, will probably only be able to fly for four years after being in an airplane, if the manufacturer of the part has not specified special instructions regarding the storage time after its manufacture. In general, aircraft maintenance is full of subtleties that both the aircraft owner, maintenance specialist and TKA inspector need to know,” says V. Plėta.

He adds that while it is the aircraft owners’ responsibility to monitor the condition of the parts required to be replaced and the full maintenance schedule, this work can be entrusted to certified companies.

  1. There is no mandatory labeling of the part.

The head of TKA’s Aircraft Department says that there is a misconception that mandatory marking is limited to clearly visible registration marks.

“Mandatory signs also include notes inside the aircraft – warning signs or marking of switches, as well as informational tables for the use of the aircraft. If the aircraft is flown by the same person all the time, unmarked switches may not cause major problems, but if the pilot is flying a particular aircraft for the first time aircraft, special markings can save his life in an emergency.

The instruction notes are very important for maintenance personnel. For example, they need to be clear about the battery voltage, the type of fuel the aircraft uses, the amount of lubricants required, etc.

During inspections, we usually come across cases where the signs are there, but they are rubbed off, faded or illegible, so we ask the aircraft owners to update them.”

  1. Aircraft defects are clearly visible.

“The greatest enemy of all vehicles is corrosion. We also find defects caused by it in aircraft. Another common type of obvious defect is improperly anchored parts, failure of countering or safety wires that fix parts in the right place, etc. It’s true, it’s gratifying that every year when inspecting aircraft, we find fewer and fewer such defects, so we hope that this trend will continue,” says V. Plėta.

  1. Improvements or modernizations of the aircraft are not recorded, or they are not in compliance with the applicable airworthiness standards.

Every improvement or modernization of a certified aircraft must be registered and documented in accordance with the requirements set by the European Aviation Safety Agency (EASA). If the technical characteristics of the aircraft change after the equipment is replaced or updated, they must be reset.

“Recently, a new trend has emerged – radio stations are changed in aircraft, additional navigational equipment is installed, and light bulbs other than what was intended are added. After such modernizations, additional entries in the flight and maintenance instructions of the aircraft are required – they must specify how to deal with the new equipment and how to maintain it, and this is often forgotten. In our opinion, this can already cause flight safety problems, so until all the necessary records and instructions are supplemented, the aircraft has to stand on the ground,” says the aircraft expert.

In contrast to car MOTs, in aviation due to strict flight safety requirements, “minor defects” are not recorded that allow the vehicle to still be used. Therefore, after each inspection of the aircraft, conclusions are presented to its owner and identified deficiencies are listed, which must be eliminated in order to obtain an airworthiness certificate.

This certificate is issued for a period of one year, regardless of the size, type, model or field of use of the aircraft. It must be obtained by all aircraft registered in the Lithuanian Civil Aircraft Register – airplanes, helicopters, helicopters, gliders, motorized gliders, seaplanes, hot air balloons, motorized gliders, ultralight aircraft and hobbyist aircraft.