Continuing on from our recent coverage of foreign objects being discovered in the fuel tanks of multiple 737 MAX aircraft, it is now being reported that a much higher number of aircraft may be contaminated.

According to familiar sources in contact with Reuters, over 50 percent of undelivered 737 MAX aircraft are said to contain foreign objects; including rags, tools, production equipment and more.

A company spokesperson confirmed to media on Friday that 35 aircraft were found to contain foreign objects, however it is currently unknown what the confirmed amount is up to as of Sunday the 23rd of February.

Around 400 737 MAX jets are grounded around the world and are patiently awaiting certification from aviation regulators, including the Federal Aviation Administration (FAA), which is facing its own criticism for their initial work certifying the aircraft.

We have contacted Boeing about foreign object debris in the 737 MAX and we will update this article, if a response if provided.

The FAA is unaware of how many aircraft are affected but confirms that Boeing has launched voluntary inspections of the 737 MAX, to eliminate any foreign object debris. Additionally, the FAA has increased surveillance based on initial inspection reports and plans to take any required action based on the findings.

Already known for foreign object identification in the 767-based KC-46 tanker, and the 787 Dreamliner, Boeing released a memo to employees stating that the discovery of foreign objects in aircraft is “unacceptable and won’t be tolerated on any Boeing aircraft when it’s delivered to the customer”.

At this time it remains unknown if this development in the 737 MAX crisis will delay certification and re-entry into service.

This article will be updated as more information becomes available.