The regulations have been covered by others as it pertains to fixed wing aircraft, but ron77584 also mentioned a helicopter. A helicopter can be operated at much lower minimums than a fixed wing aircraft as long as it abides by 91.119 as stated by others. A few years ago I was at the FSDO and got talking regulations with a few of the guys and the topic of the difference between fixed wing and helicopter compliance of 91.119. I’ll try to summarize that discussion.
Although it might be helpful to try and define what is a congested area. I was taught a
rule of thumb a long time ago that any town or area highlighted in yellow on a FAA sectional map would be considered congested.
First, all aircraft must abide by part 91.119 but it also differentiates between aircraft. There are different paragraphs that do this. There is nothing that differentiates any aircraft type in paragraph (a) which reads;
Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.
So, if you have any problem while flying any aircraft that causes a forced landing, such as a power failure, and you cause “undue” hazard to persons of property on the surface. You were not flying at an altitude necessary for safety. BTW the definition of “undue” was ambiguous at best.
Second, Helicopters are further defined in paragraph (d);
Helicopters, powered parachutes, and weight-shift-control aircraft. If the operation is conducted without hazard to persons or property on the surface—
(1) A helicopter may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section, provided each person operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA; and
A helicopter can be operated in a congested area and be closer than the minimums stated by others of 500 ft. This is allowed because a helicopter is more maneuverable in a power failure (autorotation) than a fixed wing aircraft. A competent helicopter pilot can put a helicopter down in a 100x100 ft area.
To answer the question, if the fixed wing aircraft pilot observed he was 500 ft AGL (this is an unexact science using your "eyeometer" the same way you judged he was at 400 AGL) and he didn’t damage anything on the ground, he was operating within the regulations. The helicopter was also within regulations because he also didn’t damage anything on the ground.
The part where you mention the pilot mentioning the 700’ was most likely due to routes and altitudes that were prescribed by the FAA that can be found in the Chart Supplement, Sectional, Terminal, or Flyaway charts. A local operator can also have an SOP (Standard Operating Procedure) that would regulate how their pilots fly in and out of certain airports.
Hope this helps clarify helicopter operations vs fixed wing. BTW quick hint on how to tell altitudes of other objects around the drone using your camera or FPV. If you have your camera level anything touching the horizon is at your same altitude.
As for the right of way rules, I think 91.115 paragraph (e) applies here. It states; Special circumstances. When aircraft, or an aircraft and a vessel, approach so as to involve risk of collision, each aircraft or vessel shall proceed with careful regard to existing circumstances, including the limitations of the respective craft.
Drones are usually the size of birds and depending on the circumstances the pilot many not be able to see the drone until avoiding a collision may exceed the limitations of the aircraft. Therefore in the eyes of the FAA the drone is responsible to see and avoid other air traffic.[/Q
A question to you Ron, An F-15 Is flying down a valley at 150ft above the valley floor, it is class G airspace, it collides with a drone.
Who if anyone is at fault in your opinion?
We already know the drone operator is always going to be at fault but I am just pointing out that we are out there flying legally and we do not want to be the cause of an accident and will do everything we can to avoid one but we are on the ground which limits our visibility watching the drone