Raytheon Technologies Corp. stock fell 5% during premarket trading on Tuesday, putting it on course for a new nine-month low after the company announced that it needed to remove Pratt & Whitney engine from service earlier than anticipated for inspection.

In a press release, the company stated that this issue had “recently come to light”. It added that the engine business had determined that a condition rare in powder metal, which is used to manufacture certain engine parts, will require an accelerated fleet check.

This issue will not affect engines currently in production, but “significant” portions of the PW1100GJM engine fleet that powers the Airbus A320neo narrow-body family of airliners will need to removed and inspected over the next nine to twelve months. About 200 of these accelerated removals are due by mid September.

The company stated that it is “working to minimize operational impact and support its clients.” The management will provide more detail during its earnings call, scheduled at 8.30 am Eastern.

Raytheon RTX +0.64% will acquire Pratt & Whitney in 2020 as part of a merger-of equals transaction with United Technologies Corp. The company announced recently that it will change its name from to RTX Corp. by July 28.

In a client note, Vertical Research Partners analyst Robert Stallard said: “Given the fact that RTX had hosted an investor’s event at Paris Air Show just last month, this was not a surprising set of results.”

This new issue with the GTF is another blow to the stock, especially when it comes on top of existing MRO problems. The upcoming earnings report will provide more details about the GTF issue. This is likely to overshadow RTX’s otherwise solid operating performance in the 2Q,” he wrote.

Vertical Research rates Raytheon stock as a Buy.

Raytheon’s net income for the third quarter was $1.327 billion or 90 cents per share. This is up from $1.304billion or 88cents per share in the same period last year. The adjusted earnings per share came in at $1.29, which was higher than the $1.18 FactSet consensus.

Sales increased to $18.315 Billion from $16.314 Billion, also exceeding the $17.683 Billion FactSet consensus.

The company expects a full-year cashflow of $4.3 billion down from $4.8 billion. It also expects an adjusted EPS between $4.95 and $5.05 compared to the previous guidance of $4.90 – $5.05.

Sales will be in the range of $73,0 billion to $75,0 billion. This is an increase from previous guidance which was $72,0 billion to 73,0 billion.

The S&P 500 Spx, +0.40% is up 18.6% in comparison to the stock.