A new safety flaw has reportedly been discovered on the troubled Boeing 737 Max that could further delay its return to service following two fatal crashes.

The company informed the US aviation regulator last month that it is looking into whether two sections of wiring that control the tail of the aircraft are too close together and could cause a short circuit.

Boeing said that it had identified the issue as part of a “rigorous” inspection process and was now “working with the Federal Aviation Administration to perform the appropriate analysis”.

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It has not decided whether any change is needed to the aircraft design.

The wiring was not a factor in the two crashes, in which 346 passengers and crew were killed in Indonesia and Ethiopia, but is linked to the motor that moves the horizontal tail stabiliser, the control surface that suffered malfunctions.

The wiring trouble may also affect the Boeing 737 NG, of which 6,800 are in service, according to a New York Times report.

The latest potential setback to the 737 Max came as American Airlines revealed it had agreed a confidential compensation deal with Boeing for financial damages caused by the aircraft’s grounding last March.

The US carrier said in October that it expected a $540 million hit to its annual profit as a result of the grounding of the Max.

The airline, the second largest operator of the aircraft, said that discussions continued with Boeing over compensation for Max damages beyond 2019.

American has authorised a “discretionary portion” of the settlement amounting to $30 million to be returned to staff through the company’s 2019 profit-sharing scheme in March despite the projected reduction in annual operating income for 2019 as a result of the Max grounding.

Chairman and chief executive Doug Parker said: “Despite the ongoing challenges the grounding has brought, American Airlines team members continue to do an incredible job caring for our customers.

“Our ability as an airline to weather these unprecedented times is thanks to our phenomenal team, and it was important to us that we get a deal done before the end of the year.

“On behalf of the board of directors, we are proud to take the step of including this compensation in our 2019 profit-sharing programme, even though the compensation will be received over several years.”