[Capt Spaulding]

Originally Posted by Dadhawk

Thanks for posting that. Great read.

You can't calculate exact density altitude without knowing what the barometric pressure is, but given what you said, I think you nailed it with that assessment there.

The standard temperature at 7,000ft is 34F. The rule of thumb is to add 120ft for each degree above standard temperature. So, the approximate density altitude for that day was 7000+((100-34)*120) or 14,920ft.

Basically, on that day at that airport a Cessna 172 with a 14,000ft service ceiling would have never made it off the runway.

Yep. For non-critical applications I just use std pressure (29.92) as a rule of thumb. Beyond the application to aviation the basic lesson for me is that disasters usually result from a chain of fuckups and trying to short circuit a process usually means you miss one or more chances to catch the problem before it bites you in the ass.