Eric Reyes
Filing Flight Plan
- Joined
- Mar 5, 2018
- Messages
- 7
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Eric R
I have found a number of errors in the ForeFlight Flight planning engine.
I planned a flight in a Cessna 172S traveling 55 miles at 4,500 feet at 2,400 rpms with a cruise true air speed of 108 knots. I exported this flight from the Maps page to the Flights page and then viewed the Navlog on the Flights page. The NavLog automatically calculates the top of descent (TOD) waypoint, but the true air speed show on the NavLog from top of descent (TOD) to my destination is only 53 knots. That crazy slow!
The stall speed clean config in the 172 is 48 knots. No way would anyone descend from TOD at only 53 knots TAS. I selected the standard performance profile in ForeFlight for the Cessna 172 and it doesn’t allow you to edit the descent speed or RPM’a and the only information it provides on the aircraft performance profile page for descent is “500 feet per minute”. There is no way to edit the descent rate or speed in a standard performance profile.
Any advice? Am I crazy or is this 53 knot true air speed from top of descent way too slow? I even tried a few different airplanes with the stock performance profiles and they were all way too slow for true air speed from top of descent. For example the Cirrus SR22T had a true air speed in the NavLog from top of descent of 74 to 87 knots. That way too slow for decent speed in a SR22T. Same thing for the Piper M350 Mirage.
The other anomaly that I found in ForeFlight is the course on the Map page NavLog being 2 to 4 degrees different from the bearing on the Flights page NavLog. On the Maps page I chose a departure date 1 week in advance so that the Maps Page NavLog will show course instead of heading. I then exported the flight to the Flights page and viewed the Flight page Navlog. On the Flights page NavLog there is a column titled BRG (bearing). The bearing between waypoints show here on the Flights page NavLog are 2 to 4 degrees different from the courses between waypoints shown in the Maps Page Navlog.
Correct me if I’m wrong but shouldn’t course and bearing be the exact same when in the pre-Flight planning stage and the assumption is that you stay on course so your bearing should always be equal to the course?
What am I missing here?
I planned a flight in a Cessna 172S traveling 55 miles at 4,500 feet at 2,400 rpms with a cruise true air speed of 108 knots. I exported this flight from the Maps page to the Flights page and then viewed the Navlog on the Flights page. The NavLog automatically calculates the top of descent (TOD) waypoint, but the true air speed show on the NavLog from top of descent (TOD) to my destination is only 53 knots. That crazy slow!
The stall speed clean config in the 172 is 48 knots. No way would anyone descend from TOD at only 53 knots TAS. I selected the standard performance profile in ForeFlight for the Cessna 172 and it doesn’t allow you to edit the descent speed or RPM’a and the only information it provides on the aircraft performance profile page for descent is “500 feet per minute”. There is no way to edit the descent rate or speed in a standard performance profile.
Any advice? Am I crazy or is this 53 knot true air speed from top of descent way too slow? I even tried a few different airplanes with the stock performance profiles and they were all way too slow for true air speed from top of descent. For example the Cirrus SR22T had a true air speed in the NavLog from top of descent of 74 to 87 knots. That way too slow for decent speed in a SR22T. Same thing for the Piper M350 Mirage.
The other anomaly that I found in ForeFlight is the course on the Map page NavLog being 2 to 4 degrees different from the bearing on the Flights page NavLog. On the Maps page I chose a departure date 1 week in advance so that the Maps Page NavLog will show course instead of heading. I then exported the flight to the Flights page and viewed the Flight page Navlog. On the Flights page NavLog there is a column titled BRG (bearing). The bearing between waypoints show here on the Flights page NavLog are 2 to 4 degrees different from the courses between waypoints shown in the Maps Page Navlog.
Correct me if I’m wrong but shouldn’t course and bearing be the exact same when in the pre-Flight planning stage and the assumption is that you stay on course so your bearing should always be equal to the course?
What am I missing here?