No, 40 minutes is not enough time. I fly in and out of ATL
for a living and folks are always missing their connections because they book 30-45 minute connection times. Airlines are NOT well oiled machines, despite popular belief. Any number of things can go wrong, and a 15 minute delay could be detrimental to your itinerary. MX
problems, gate unavailable upon arrival in ATL
, ATC equipment failures, ground stops to ATL
, call for release programs to ATL
, taxi delays from runway 10/28 in ATL
, runway closure in ATL
, ramp congestion in ATL
, ground stops to Houston, ground stops for departures in Houston due to Houston Center airspace saturation...I could list dozens of more things that routinely cause 10-15+ delays in ATL
1 hour minimum. Always.
EDIT: FL operates from both C and D concourses in ATL, and should you have to change concourses and experience a 10-15 minute delay on your inbound flight to ATL...you may not make it.
Consider this: Weather is beautiful and clear. Your flight arrives in HOU 10 minutes late due to taxi delays in ATL, despite your flight having left the gate on time. A booking discrepancy occurs in HOU, causing an additional 5 minute delay. You depart HOU 15 minutes late. Upon arrival in ATL airpace, your flight is slowed to 250KTS for entrail spacing, and ATC issues several 90 degree turns as spacing vectors. Now you have an additional 5 minute delay. Contacting ATL approach control, your flight is assigned runway 28 (common for west arrivals) and it takes an additional 15 minutes to fly the downwind leg on the arrival and additional time for taxi. You park at concourse D and need to go to C, which takes about 5 minutes...as much as 10 if you park at D1 and need to go to C1.
10 minute taxi delay + 5 minute booking delay + 5 minute ATC delay + 15 minute arrival delay + 10 minute concourse change = 45 minutes. BAM: missed your flight.
This, my friend, is a standard ATL day. I know, because I do it 5 times a day.
[Edited 2008-10-25 17:25:52]