Hi John,
Thanks for your input. You are right, according to the FARs the end of the first segment more correctly should be "when the landing gear is fully retracted." I was quoting from a John Lowery text which states the end to be at 35ft. Maybe some confusion with FAR 14 CFR 25.111 (b) (2) which mentions the requirement that acceleration to V2 must be completed by 35ft.
http://www.ecfr.gov/cgi-bin/text-idx..._1111&rgn=div8 With all due respect, both the Lowery text and FAR 14 CFR 25.121 state quite clearly that the commencement of the first segment is at the end of the take off roll, VLOF (lift off) however. This opposed to the term 'take off flight path' that refers to a start at 35ft!
The Cornell reference is a copy of the FARs. Cross-references are hyperlinked unlike the FAA site so it is a bit more user friendly but same content I believe.
Here is the FAA reference for 14 CFR 25.121:
eCFR ? Code of Federal Regulations