Boomer From United States of America, joined May 1999, 102 posts, RR: 0 Reply 2, posted (12 years 11 months 3 weeks 7 hours ago) and read 886 times:
The letter designations used to indicate a maintenance interval inspection vary by the operator. Once an operator is established with the FAA as having an engineering and maintenance reliability program. It then has the authority to define its maintenance program and intervals as long as minimum criteria are met. This often results in various phases of maintenance that suit the operator's mode of operation. This even includes how maintenance is scheduled to be done. For example, America West's maintenance program is largely calendar based, while Alaska Airlines is keyed off flight hours and cycles. To answer your question, to be sure just what is meant by an "R" check, you have to know something about the particular operator and his program. Most of the checks you listed are typical designations for various levels of inspections.
The A check is a frequent inspection (often weekly) that can usually be accomplished in a single shift by a crew of mechanics. This check performs certain functional tests of instruments, exterior lights, filter changes, servicing landing gear, checking cabin emergency equipment, etc.
The B check is an intermediate frequency inspection (often monthly) that is more comprehensive than the A check, but does not require significant disassembly. More systems are tested and some stuctural inspections may be incorporated. This check can typically be accomplished in 1-2 shifts.
The C check is a heavy maintenance visit that occurs roughly every 3,000 flight hours (remember this varies by operator). Depending on the operator's program, this may take from 5-30 days to accomplish. It is common for operators to tailor their program to take advantage of this down time by scheduling other inspections concurrently, so portions of the SID (structural inspections) along with the C check.
The D check is essentially an overhaul. These inspections generally incorporate most, or all, of lower level inspections and all the structural inspections. This type check may require up to 75 days, depending on the aircraft and the intensity of the maintenance requirements. Not all operators have a separate D check, but rather segment the items in a D check and accomplish these items incrementally during the C checks. When a cycle of C checks is complete, the requirements of the D check have been met.
The other letter designations you listed need to be tied to the operator to be sure of their scope of work.
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5 Reply 3, posted (12 years 11 months 3 weeks 5 hours ago) and read 879 times:
The above description was very good. It should be noted that checks are comprehensive in that they superscede one another-- The items on an "A" are included on a "B" and so on. ------ It cannot be stresed enough that checks vary in scope and interval from airline to airline. The minimum requirements are often exceeded by most airlines "on the up and up".
Tom2katie From , joined Dec 1969, posts, RR: Reply 4, posted (12 years 11 months 2 weeks 5 days 20 hours ago) and read 850 times:
The info about the letter checks (a,b,....) is right on. The other checks you listed are probably specific to some airlines particular maintenance program with the exception of the SID inspection. These are a part of the FAA's aging aircraft mandate and stand for 'structural integrity defect' inspections. They usually deal with cracks or corrosion in specific areas of know failures. They come up at regular intervals usually based on Aircraft total time or cycles. In addition to these, you also can have a AAIP, CAP, CAMP and so on inspection program. Each airline incorporates their own program which is then accepted (not approved) by the FAA. Hope this helps.