UPDATE 1-Aeroplan makes C$100 mln loan to Air Canada

* Air Canada has already drawn down C$79 mln

* Loan is secured by stake in Air Canada Vacations

* Remits C$40 mln to Aeroplan

VANCOUVER, British Columbia, June 29 (Reuters) - Groupe Aeroplan Inc (AER.TO), which operates Air Canada's (ACa.TO) frequent flyer program, has agreed to lend the cash-strapped airline up to C$100 million ($86 million), both parties said on Monday.

Air Canada, the country's biggest airline, has already drawn down C$79 million of the loan.

The loan comes at a time when many in the industry are concerned that Air Canada, hobbled by debts, may be forced into bankruptcy protection for the second time in six years.

The secured, revolving loan is available until June 30, 2010, and is secured by Air Canada's interest in Air Canada Vacations, which specializes in custom holiday packages.

Air Canada is required to raise at least C$600 million from lenders under the terms of a set of tentative agreements reached with its Canadian-based unions this month on a moratorium on funding its pension fund, .

If it is able to raise the money, the carrier said it will terminate the loan agreement with Aeroplan.

Air Canada has said it is in talks with several lenders. One is Export Development Canada, a federal financing agency, which it is understood to have asked for C$200 million.

The airline said in a statement it has repaid about C$40 million to Aeroplan to reverse amounts it had received from the company under a November 2008 prepayment agreement.

($1=$1.16 Canadian) (Reporting by Nicole Mordant; editing by Rob Wilson)