a bypass duct arranged circumferentially around a central axis of the gas turbine engine and configured to direct a flow of air through the bypass duct, the bypass duct including an outer wall defining an outer boundary of a flow path of the flow of air and an inner wall defining an inner boundary of the flow path of the flow of air, the outer wall formed to define an access opening adapted to allow access into the bypass duct from radially outside of the outer wall, and

a heat exchanger assembly removably coupled with the outer wall and configured to transfer heat from a cooling fluid to the flow of air passing through the bypass duct, the heat exchanger assembly including an access panel removably coupled with the outer wall to cover the access opening, a heat exchanger adapted to receive the cooling fluid therein and coupled with the access panel for movement with the access panel in response to the access panel being uncoupled from the outer wall, and a shroud extending between the access panel and the heat exchanger and configured to collect a first portion of the flow of air and direct the first portion through the heat exchanger and allow a second portion of the flow of air to flow around the shroud without passing through the heat exchanger,

wherein the heat exchanger assembly extends entirely from the outer wall of the bypass duct to the inner wall of the bypass duct.