Thanks Turbine D for the links. I'm a little surprised at the runway length for a 737-900 at Dayton. I read the FAA document, and in the Appendix 3, they actually give an example using the 737-900. Coincidently at the same elevation and design temperature as the Dayton study. That FAA example was a runway length of 9,000 feet - not 12,800 feet - which fits better with my experiences.