Maintenance times.

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Maintenance times.

Post by joefremont » Wed Apr 07, 2021 9:39 pm

Hi flyers

I had a pilot complain about how long it took to get there aircraft through a C check and though I would bring it up here to see what everyone thinks about the time for aircraft maintenance.

Currently an A check takes 1 day, a B check 3, a C check 7 and a D check 14.

What do you think is that time too long, too short or just right. These times were set when the site was first created many years ago and we have never really had a reason to revisit them.
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Re: Maintenance times.

Post by BVU-951 » Wed Apr 07, 2021 9:48 pm

I personally think they are just right. As it helps make pilots take more care with their flying.
I expect it is only the Antonov 225 pilots that would want shorter maintenance times, as all other aircraft can be replaced with a spare while one is being worked on.

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Re: Maintenance times.

Post by jato0072 » Thu Apr 08, 2021 5:24 am

Yes. Please leave it. Maintenance takes time. Which is why additional airframes are good to have in the fleet to keep operations moving.

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Re: Maintenance times.

Post by Cat » Thu Apr 08, 2021 4:32 pm

Looking at what is involved in the real world, I think we are spot on for virtual vs real world in our "accelerated life cycle" of virtual airline flying.

It should also be noted that our virtual airlines can avoid more lengthy and costly B-C-D checks by simply performing A checks before their aircraft reaches 95% overall status. I am unsure of the C and D check status thresholds, but anyone who runs their aircraft down that far needs an "expensive time out" anyway. Crashes that require a D check I sometimes think there should be a maximum fpm number where Humpty Dumpty can no longer be put back together again, the aircraft is written off at scrap value and the airline has it removed from service. NO I am not pushing for that as the haters will start posting feverishly. I'm just saying we have it far easier than the real world and our system needs no changes.

Real world maintenance:

A check
The A check is performed approximately every 400-600 flight hours, or every 200–300 flights, depending on aircraft type. It needs about 50-70 man-hours, and is usually performed in an airport hangar. The A check takes a minimum of 10 man-hours. The actual occurrence of this check varies by aircraft type, the flight cycle count, or the number of hours flown since the last check. The occurrence can be delayed by the airline if certain predetermined conditions are met.

B check
The B check is performed approximately every 6-8 months. It takes about 160-180 man-hours, depending on the aircraft, and is usually completed within 1–3 days at an airport hangar. A similar occurrence schedule applies to the B check as to the A check. B checks are increasingly incorporated into successive A checks, i.e. checks A-1 through A-10 complete all the B check items.

C check
The C check is performed approximately every 20–24 months, or a specific number of actual flight hours (FH), or as defined by the manufacturer. This maintenance check is much more extensive than the B check, requiring a large majority of the aircraft's components to be inspected. This check puts the aircraft out of service for 1–2 weeks. The aircraft must not leave the maintenance site until it is completed. It also requires more space than A and B checks, therefore, it is usually carried out in a hangar at a maintenance base. The effort needed to complete a C check is up to 6,000 man-hours.

D check
The D check, sometimes known as a "heavy maintenance visit" (HMV), is by far the most comprehensive and demanding check for an airplane. This check occurs approximately every 6-10 years. It is a check that more or less takes the entire airplane apart for inspection and overhaul. Even the paint may need to be completely removed for complete inspection of the fuselage metal skin. Such a check can generally take up to 50,000 man-hours, and 2 months to complete depending on the number of technicians involved. It also requires the most space of all maintenance checks, and as such must be performed at a suitable maintenance base. The requirements and the tremendous effort involved in this maintenance check make it by far the most expensive, with total costs for a single D check in the multi million dollar range.

Because of the nature and the cost of a D check, most airlines — especially those with a large fleet — have to plan D checks for their aircraft years in advance. Often, older aircraft being phased out of a particular airline's fleet are either stored or scrapped upon reaching their next D check, due to the high costs involved in comparison to the aircraft's value. On average, a commercial aircraft undergoes two, or three, D checks before being retired.

Manufacturers often underestimate the cost of the D check. Boeing underestimates the cost for four of its aircraft, and the expectation is that they have underestimated it for the B787-9 which in 2018 had not been in service for long enough to have been put through a D check.

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