conflicting height information question

[adwb]

I have a question for you all.

. I understand that regardless of the height above sea level , currently a drone may be operated up to 400 feet above take off point in the UK.

A helicopter or light aircraft should not, without permission , go below 500 ft.

BUT the Helicopter/aircraft's height is based on a altimeter reading that is based on sea level being zero.

So a plane flying at 500 ft above sea level could be below a drone that has taken off from a 200 foot above sea level hill and is flying at 400 ft. I am I wrong if so how????

 

[licensed pilot]

A pilot, any pilot, is (or should be) aware of the terrain below and understand how the altimeter works. A general aviation aircraft altimeter is merely a barometer, calibrated for air pressure at a given altitude

Say my airplane altimeter shows 900 ft. with the correct setting (baro pressure), I should know that is MSL altitude, not true altitude above the ground. If my chart shows the ground to be 500 feet, then my airplane is at 400 feet. Just a little mental gymnastic pilots are trained to do. You pilots jump in if I messed up.....

 

[Steve@AerialImagesPro]

Heli’s are allowed under 500 ft if they’re landing, so all they’d have to say is that they were landing, which is why when a heli is around it’s best to be extra careful.

Police and news helps must have special clearance or something because I see them flying below 500’ all the time.

 

[natnatroswell22]

So a plane flying at 500 ft above sea level could be below a drone that has taken off from a 200 foot above sea level hill and is flying at 400 ft. I am I wrong if so how????

You are right in this case but normally helicopters fly thousands of feet though.

 

[Birdseye]

I have a question for you all.

. I understand that regardless of the height above sea level , currently a drone may be operated up to 400 feet above take off point in the UK.

A helicopter or light aircraft should not, without permission , go below 500 ft.

BUT the Helicopter/aircraft's height is based on a altimeter reading that is based on sea level being zero.

So a plane flying at 500 ft above sea level could be below a drone that has taken off from a 200 foot above sea level hill and is flying at 400 ft. I am I wrong if so how????

Theoretically you are wrong, as if a helicopter passes over the point that you took off from he should be 500' above you....*if* he is complying with the letter of the law.

The UK 500' minimum rule is from the ground or nearby objects:

(b) The 500 feet rule
Except with the written permission of the CAA, an aircraft shall not be flown closer than 500 feet to any person, vessel, vehicle or structure.

In addition there are further restrictions when flying over towns etc. :

(c) The 1,000 feet rule
Except with the written permission of the CAA, an aircraft flying over a congested area of a city town or settlement shall not fly below a height of 1,000 feet above the highest fixed obstacle within a horizontal radius of 600 metres of the aircraft.