CFM International Inc. says 68 jet engines were fitted with spare parts backed by fraudulent documentation from a little-known UK-based supplier, a sign that fake components may have been installed on certain older-model aircraft.

The finding was included in a lawsuit filed by the joint venture of General Electric Co. and Safran SA in the UK against closely held AOG Technics Ltd, according to a statement from CFM. The suit seeks an injunction to force AOG to provide more information to aid the aviation industry’s search for suspect components.

“Safety is our first priority, and we are taking aggressive legal action against AOG Technics to accelerate the industry’s ability to identify parts sold by this third-party with falsified documentation,” a CFM spokesman said in a statement.

Representatives for AOG could not be reached for immediate comment.

The development provides the first hint at how many older-generation Airbus SE A320 and Boeing Co. 737 aircraft may have been fitted with spare parts that London-based AOG allegedly sold with falsified airworthiness records. It’s unclear whether additional engines may have used unauthorized replacement parts.

Regulators, airlines and other industry players have since been scouring their records to hunt down the suspect components sold by AOG, the obscure supplier at the center of the crisis. AOG has no direct affiliation with CFM or its partners.

To date, CFM and GE Aerospace have found 78 documents they say are falsified and which cover 52 CFM56 engine part numbers, along with two faked records for CF6 components.

No incidents linked to the suspect parts have been identified, the companies have said.

The European Union Aviation Safety Agency earlier this week determined that the components backed by forged documentation included turbine blades, a critical component of an aircraft’s propulsion system.

“We remain fully engaged with aviation regulatory authorities to support their investigations into AOG Technics, and we continue to work with our customers to assess the authenticity of documentation for parts they acquired directly or indirectly from AOG Technics,” the CFM spokesman said.

— With assistance by Siddharth Vikram Philip and Albertina TorsoliAviation regulators in Europe determined AOG supplied parts for the repair of CFM56 engines, the world’s best-selling turbine, with falsified documentation, Bloomberg News reported last week.

The proliferation of undocumented parts has sent shock waves through an industry where every component requires verification to ensure aircraft safety. Without such assurance, it’s impossible to know how durable uncertified parts will be under stress.