14 CFR 121.436(a)(1) establishes a requirement for the PIC and SIC to hold an airline transport pilot certificate. Nowhere in the regulation is a stipulation found that requires 1,500 hours to serve as SIC under Part 121. Only that the SIC hold an ATP pilot certificate that is not subject to the limitations of 14 CFR 61.167.

In turn, 14 CFR 61.167(b) stipulates that the holder of an ATP certificate who has not met the age or experience requirements of 61.153(a)(1) and 61.159 bears certain limitations regarding acting as PIC, and in acting as SIC in certain crew compliments.

Nowhere in Part 121 is a stipulation found dictating that the SIC must hold 1,500 hours. Only an ATP. The experience requirements for the ATP have various levels, depending on the means used to meet the regulation. 1,500 hours is mitigated by various other experience and qualification, and is not a hard and fast number. The requirement of 1,500 hours for the ATP has been around a very long time, and well predates Colgan.

The means of understanding the regulation are threefold: first is the preamble to the federal register in which the final rule was announced; second is the FAA Chief Counsel legal interpretation of the regulation, and last is the regulation itself. One who wishes to understand the reasoning of the more recent changes to the ATP experience requirements, including provisions for military pilots and other means of meeting the ATP experience requirements, would do well to read the Federal Register preambles before pontificating about that which (s)he does not understand.

https://www.federalregister.gov/docu...ools-and-other

https://www.federalregister.gov/docu...ier-operations

Additionally, the change to Part 121 itself, establishing the requirement for the ATP for SIC's operating under that part, also has a preamble with legal explanation of the rationale for the regulation. Read it:

https://www.federalregister.gov/docu...ical-amendment

Nowhere in that preamble is a requirement established for a SIC in Part 121 operations to have 1,500 hours. The requirement for the SIC to hold an ATP certificate IS established, however, along with all the rationale for the change, and the rationale establishing that a PIC must have 1,000 hours in air transport service.

If one continues to beat one's empty noggin on the stairs and insist that it's a 1,500 hour rule, it's a clarion call that directs all present to look to the stupid person, banging his head on the steps. Clue in, brightspark. Banging your head or parroting the same, tired lies and misinformation, won't make you any smarter.