Automatic RTH and low battery warning with 73% battery?

[Phantom751874]

Fair enough, sorry I misinterpreted the intent of your post.

The FAA guidelines state to stay under 400ft. They are guidelines and not laws. It's a good idea to stay below this if you don't want to stir up trouble. However, class G airspace (typically under 1,200 ft AGL which means Above Ground Level) is not really regulated, although it IS the FAAs jurisdiction. Class G is much shorter near and around airports and other areas. You could take a look at aeronautical charts if you are really curious, but there is no need unless you are an actual pilot at this time.

I'd recommend staying under or around 400ft unless you are in the middle of no where where you will not draw attention. If someone complains and the cops come, it's easier if you just say that FAA guidelines say whatever, and you are adhering to them. It's not that you'd be breaking any laws necessarily, it's just an easier argument to authorities.

My serikous question though, and I don't have my Phantom here to see, is the reading in the pilot app AGL (Above Ground Level) or MSL (above Mean Sea Level)?

EDIT: I THINK that the phantom has a max ceiling (Pilot app settings) of 400m AGL, but I could be wrong. This is just a bit above 1,200ft

P3 is limited to 500 meters.

 

[Brianroberts]

The altitude is reported as height above take-off elevation thus it is a relative measurement to the ground and not exact.

Ok, so assuming you're taking off somewhat close to the ground, it's AGL.

 

[N017RW]

Not because of an assumption (if that's what you meant).

Whatever the atmospheric pressure is at time of take-off is considered to be the ground or zero feet altitude.
All altitude reports are relative to this initial pressure..

 

[Brianroberts]

Not because of an assumption (if that's what you meant).

Whatever the atmospheric pressure is at time of take-off is considered to be the ground or zero feet altitude.
All altitude reports are relative to this initial pressure..

It can't be pressure when GPS is available, is it? In an actual airplane, altimeters (using ambient pressure) has to be adjusted based on different atmospheric conditions, both on the ground AND in the air generally based on weather predictions and readings.

 

[N017RW]

Yea on the adjustments
That's why it's so inaccurate on the Phantom.

GPS is not used for altitude on these craft. (It's not that good either).

 

[ctp]

Can someone please help me understand what happened ?
How can it initiate RTH and give me a low battery warning when I have 73% battery? Does it take into account the distance from home point ?

Pretty impressive that it got to 17,050 feet (over 3 miles) with only 28% battery usage. To answer your question, it does take home point into account and calculates when it needs to turn around to reach home at 30% battery, to avoid the situation you experienced hitting 10% 1500 feet from home and a forced auto-landing.

I'll testing the same in a couple of weeks when I head out to the ranch where I have a 5 mile level area with no EMI (except one low voltage power line), no water and clear line of site

 

[iahphantom]

When converting the data log file and importing into dashware it reports it above sea level. The data shown on the pilot app determines where you are and makes your home point 0 feet regardless of how high above sea level you are. So the raw data and pilot app show different information when it comes to height.

 

[jhamby]

EDIT: I THINK that the phantom has a max ceiling (Pilot app settings) of 400m AGL, but I could be wrong. This is just a bit above 1,200ft

In my settings, it is 500m AGL allowed, and I have flown over 400m AGL before.