zzfriend
New Member
Got a new way of looking at density altitude last summer, flying our A-1B on amphibs from Florida to Washington. From Sidney NE to Rawlins, WY: took off about 10 am on the second leg of the day, but by the time I got north of Cheyenne, way downwind of Elk Mountain, the day was getting warm.
It was a nice demonstration that service ceiling can go down fast, sometimes -- at one point I was thermalling at climb power to get over a thousand feel agl. (The only time my GPS 496 ever failed, of course, was then.)
Now when I fly that route I have this image of a big herd of Wyoming elephants trampling down my service ceiling as the day goes on, squashing it lower minute by minute.
It might have been no problem on wheels, but for a while I was keenly aware that amphibs add a bit more weight and drag than they do lift.
Here was the chain:
mid-morning takeoff
high country
full gross
amphibs
west wind
line of hills west (downdrafts in the lee)
OAT increasing
high power required
oil temp increasing
oil pressure decreasing (within limits, but still not pleasant to watch)
reaching for the map when the GPS failed.
Density altitude at Rawlins was 10,400 when I landed.
Next day I thought I'd try airborne before sunup. Worked well.
It was a nice demonstration that service ceiling can go down fast, sometimes -- at one point I was thermalling at climb power to get over a thousand feel agl. (The only time my GPS 496 ever failed, of course, was then.)
Now when I fly that route I have this image of a big herd of Wyoming elephants trampling down my service ceiling as the day goes on, squashing it lower minute by minute.
It might have been no problem on wheels, but for a while I was keenly aware that amphibs add a bit more weight and drag than they do lift.
Here was the chain:
mid-morning takeoff
high country
full gross
amphibs
west wind
line of hills west (downdrafts in the lee)
OAT increasing
high power required
oil temp increasing
oil pressure decreasing (within limits, but still not pleasant to watch)
reaching for the map when the GPS failed.
Density altitude at Rawlins was 10,400 when I landed.
Next day I thought I'd try airborne before sunup. Worked well.
