Chief executive of the company, Willie Walsh, announced last month that he would work in July for no pay – forgoing £61,000 in salary. His chief financial officer Keith Williams will also go without pay in July.
The request to staff comes after the airline initially asked them to accept a pay freeze, and volunteer for unpaid leave.
The letter to its employees said: “Colleagues are being urged to help the airline’s cash-saving drive by signing up for unpaid leave or unpaid work. From tomorrow, people will be able to opt for blocks of unpaid leave or unpaid work, with salary deductions spread over three to six months, wherever possible.
“The new unpaid work option means people can contribute to the cash-saving effort by coming to work while effectively volunteering for a small cut in base pay.”
BA said the move would “help minimise the financial impact on individuals, while helping to immediately save cash for the business.”
Chief executive Walsh said: “I am looking for every single part of the company to take part in some way. It really counts. We face a fight for survival.
“These are the toughest trading conditions we have ever seen and there simply are no green shoots. Our survival depends on everyone contributing to changes that permanently remove costs from every part of the business.”
Employees wishing to volunteer for unpaid work would have to apply by June 24.
BA is still negotiating with unions over a wider package of cost-cutting measures expected to include the loss of 4,000 jobs – one in 10 of the workforce – which has led to fears staff could pursue industrial action later this summer.
The company is also asking staff to consider temporary or permanent part-time work, short-term unpaid leave of up to four weeks, or long-term unpaid leave of between one and 12 months.