Rust debris has begun falling from the structure, meaning passengers are using an alternative entrance to the terminal building.
The problem became apparent during the afternoon of 21 August.
Passengers on inbound Aurigny flights are instead having to use the entrance set up to keep social distancing during the pandemic.
The concrete legged control tower is several decades old and has a number of steel elements to it.
An engineering inspection will take place today, 22 August.
Work was due to be underway by now on the complete refurbishment of the airport, including lengthening the runway.
But it has been paused, after it came in £13M over budget.
More affordable alternatives are being considered.
Guernsey's Victor Hugo Centre reaches fundraising milestone and unveils sculpture
Guernsey's police complaints process not 'in crisis'
Guernsey could be disgraced Andrew’s new home - Royal biographer
Guernsey Museums close for the season
First visit of an EU ambassador to Guernsey
Hotel guests help grow a greener Guernsey
Guernsey man seeks donations after 2,000-mile challenge
Charity funds upgrades at Guernsey swimming pool
