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Military Aircraft: Helicopters

Volume 472: debated on Monday 3 March 2008

To ask the Secretary of State for Defence how many flying hours helicopters can undertake before they must be taken out of service, broken down by type of helicopter. (189269)

Different helicopter types have differing Structural Integrity design philosophies. They do not all have a set number of flying hours before they must be taken out of service as indicated in the following table.

Aircraft type

Finite life—designed fatigue life-flying hours

Agusta A109A/AM


Attack Helicopter

Yes—9,000 hours

Chinook Mk2/2a



Yes—15,000 hours

Lynx Mk3, Mk7, Mk8, Mk9

Yes—7,000 hours

Merlin Mk1 and Mk3

Yes—10,000 hours

Puma HC1


Sea King Mk3/3a, Mk4, Mk5 Mk6c, Mk7


The structural integrity of airframes is assured by regular maintenance and replacement of fatigue-sensitive components after a set period of use. In all cases, the maintenance policy and lives of key components are regularly reviewed to ensure it supports the safe operation of the aircraft. Helicopters with designed fatigue lives can fly beyond the design life when specific actions are taken. Actions may include the replacement of significant structural items and the instigation of enhanced inspections and maintenance.