Ask Captain Dan: How often do big airline jets have to be serviced ? Our Resident Pilot Answers Flight Questions.

Toronto ON – Pilot Dan Baz is answering your flying questions here on the Cornwall Free News.


If you have a question about flying you can email Captain Dan or post below.



How often do big airline jets have to be serviced ?  I have to take my car to a garage for servicing every 10,000kms.
Question asked by Kent.


There are certain items that must be checked before every flight.  More items need to be checked every 48 hours.

All aircraft have to be maintained according to an approved maintenance program approved by Transport Canada.  Airlines and airworthiness authorities (Transport Canada, FAA in USA)  casually refer to the detailed inspections as “checks”:  A check, B check, C check, or D check.
“A check”  is performed approximately every 500 – 800 flight hours. The actual occurrence of this check varies by aircraft type, the cycle count (takeoff and landing is considered an aircraft “cycle”), or the number of hours flown since the last check.
“B check”   is performed approximately every 3-6 months. It usually takes 1-3 days to complete the check. A similar occurrence schedule applies to the B check as to the A check.
“C check”  is performed approximately every 15–21 months or a specific amount of actual Flight Hours as defined by the manufacturer. This maintenance check is more extensive than a B Check, as pretty much the whole aircraft is inspected. This check puts the aircraft out of service for 1 to 2 weeks.
“D check”  is, by far, the most comprehensive and demanding check for an airplane.  This check occurs approximately every 5–6 years. It is a check that takes the entire airplane apart for inspection and overhaul. Such a check can generally take up to 2 months, depending on the aircraft and number of technicians involved. It is not uncommon to have as many as 100 technicians working on a Boeing  B747 at the same time, plus many more in the component overhaul shops.

A bit more about Captain Dan:


Captain Dan Baz enrolled in Flight School at the age of 16.

He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.

Over the last four decades he has flown thousands of hours up in the blue sky.


Have a question for the Captain ?  Send it to Captain Dan Baz Every week a question from the readers will be selected and answer posted in this column.


Best Western

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