Two interview questions
10-08-2007, 06:39 PM
#3
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Joined APC: Jan 2006
Position: Engines Turn Or People Swim
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2) Generally you want less-dense air (less drag), which always means higher altitudes. But the tradeoff is that it at takes a lot of gas to climb to higher altitude, so on a shorter flight it may not be economical to burn the gas to get to F390 only to have to immediately start your descent. Also high-altitude winds play an important role. You may better of at F290 with a 30 kt headwind than that at F390 with a 130 Kt headwind.
These are typical CRJ altitudes (westbound, no unusual wind):
15 min flight: 16,000
30 min flight: F240
1 hour flight: F320
> 1 hour flight: F380
10-08-2007, 06:44 PM
#4
Gets Weekends Off
Joined APC: Jan 2006
Position: Spartan
Posts: 3,652
1) In addition to what Joe said, a strong X-wind can be a factor.
2) Generally you want less-dense air (less drag), which always means higher altitudes. But the tradeoff is that it at takes a lot of gas to climb to higher altitude, so on a shorter flight it may not be economical to burn the gas to get to F390 only to have to immediately start your descent. Also high-altitude winds play an important role. You may better of at F290 with a 30 kt headwind than that at F390 with a 130 Kt headwind.
These are typical CRJ altitudes (westbound, no unusual wind):
15 min flight: 16,000
30 min flight: F240
1 hour flight: F320
> 1 hour flight: F380
2) Generally you want less-dense air (less drag), which always means higher altitudes. But the tradeoff is that it at takes a lot of gas to climb to higher altitude, so on a shorter flight it may not be economical to burn the gas to get to F390 only to have to immediately start your descent. Also high-altitude winds play an important role. You may better of at F290 with a 30 kt headwind than that at F390 with a 130 Kt headwind.
These are typical CRJ altitudes (westbound, no unusual wind):
15 min flight: 16,000
30 min flight: F240
1 hour flight: F320
> 1 hour flight: F380
10-09-2007, 09:13 AM
#5
Prime Minister/Moderator
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 40,406
10-09-2007, 09:35 AM
#6
Gets Weekends Off
Joined APC: Jan 2006
Position: Spartan
Posts: 3,652
I never liked to take the -200 over 300 unless it was winter. Never flew the -900 but the 700 had no problem up high and was actually a nice ride.
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