SALES at Co Derry firm Moyola Precision Engineering fell by 10.7 per cent last year to £12.6m.
However, bottom line profits were up in the 12 months to March 2015 to £2.1m against £1.6m in 2014 after it saved on administrative expenses and had a lower tax bill.
The company is part of Northern Ireland's strong aerospace sector and supplies plane makers such as Bombardier.
Directors said the results were "satisfactory" adding that, "challenging conditions did result in a fall in turnover, but profit margins were maintained".
In their strategic report filed at Companies House in Belfast, directors said: "Whilst the company continues to see opportunities in the aerospace sector, it is also acknowledged that conditions during the year ahead will bring significant additional challenges."
Among the projects for which the company provides parts is Bombardier's troubled C Series of planes which been beset with delays and low order numbers.
"The company has continued to invest very significantly in its facilities and has installed further major machining capacity at a cost in excess of £2 million.
"The company sees continuing investment in research and development expenditure as being core to enable it to continue to develop its status and its reputation within the industry."
They added that they were keeping the firm's reliance on the aerospace sector "under constant review".
The business is expanding its plant at Castledawson and said the extension should be completed next year.
The company's payroll grew slightly over the year to 102 making the wage bill just over £3m.
Directors' remuneration totalled just under £328,000.
Moyola provides logistical solutions for 5-axis detailed components, kits and sub assemblies for the aerospace, defence, automotive and IT sectors.
It exports to countries across the world including China, Japan, Singapore, Mexico and the United States.
