Air Law question
 

I am re studying Air Law (after many years) in a bid to get my EASA license ( now that we’re our of EU) and am using the excellent AOPA website. However came upon an interesting question and answer.

You are flying at night, in good visibility when you notice a green navigation light on a constant bearing of 340 degrees same altitude......which of the following is correct.

Of the four choices, two stated no risk of collision and two stated there was a risk of collision, the choices being a. Do nothing because you have right of way or b. Change altitude to avoid a potential collision.

The correct answer on the website was a. No action required you have right of way, perhaps technically correct, but is it a wise course of action ? If the other pilot has not seen you and you have to assume that, why would you not act to avert a potential problem, provided of course you could safely do so. Not much point claiming right of way if you subsequently hit each other !

Any thoughts ?

We're using the AOPA ground school for all of our students. I only see the "Readiness Certificates" that are issued, never the content or test questions, but I know it's an excellent system so far. Is it not possible to ask AOPA for an explanation?

You're studying law. The answers are less about how the rules might work out when applied in the real world and more, only really, about what the rules say should happen.

Remember that exam questions in 'objective' testing: require you to select from a number of fixed answers. So a personal opinion cannot be assessed. Only one answer can be correct. The answer must be wholly correct in itself, The question could be asking for just a part of the whole story. Refer back to the question with this in mind when your struggling to decide.

For the particular question with regard to lights: the three navigation (position) lights add up to 360 degrees. The red and green radiating 110 degrees each and the white tail light therefore must be radiating 140 degrees. Worth drawing this out on some graph paper to fully understand. However the answer is partly in the question. For exam technique: whenever a "constant bearing" is in the question then you must be on a collision course. Look at the question again to see if the question is regarding a 'collision' course or whether it is asking who has the 'right of way'.

For me, with regard to a right of way, the aircraft concerned is within 20 degrees of of the nose and it should be considered a head on and therefore requires a turn to the right. The question, if it is quoted correctly, is unfair because the answer requires an opinion.

Constant bearing of 90 degrees, both aircraft at same speed and heading. Are they on a collision course? Substitute any bearing you like - are they on a collision course? I suggest that you must get very nervous watching aircraft fly in formation.

Substitute anything else than a perfect parallel trajectory, and they are on a collision course. I.e. the whole universe minus the exact parallel singular line.

true, they might be on collision course but with opposite vectors - leaving away from the collision point. :}

Is it not possible for an aircraft on a divergent course but different airspeed to maintain a constant relative bearing?

Constant bearing is neither a necessary nor sufficient condition for a mid-air collision. At a minimum the aircraft must also be converging laterally and, if not already at the same altitude, must be converging vertically.

In such a situation you would see two lights: Red/Green, Red/white or Green/white.

The term 'exam technique' refers to questions normally asked in exams, the two words speak for themselves..

If you omit the second sentence, the first stops making proper sense. I admit that.

Curious how you hit something moving across the windscreen, do tell! Tehcnically speaking, I am only trained in not coming to visual range.

I take it you haven’t taken the Air Law exam.

If the other aircraft is on a constant relative bearing of 340 and a green light can be seen then the above scenario is not possible. They are on a collision course. Simple as that

No I have not. FAA has no such exam.

EXDAC,

The CAA have always maintained the view that if another aircraft is on a constant bearing, there is a risk of collision. End of story.

I'm sure there is an infinite number of scenarios, but here is one:

I fly parallel to, right of, close to, and at the same altitude as another aircraft which maintains constant heading. I roll toward the other aircraft. The first appearance of the other aircraft in my windshield is when the nose appears in the upper left corner. As I continue the turn the other aircraft's nose moves toward the lower right of my windshield. As I get closer my view of the other aircraft sweeps down the fuselage and the last thing I see, and hit, is the tail.

Thank you, no further clarifications necessary.

Question 7. of Pooley’s Rules of the Air section:

Whilst flying at night you see the green navigation light of another flying machine on a steady relative bearing of 330 degrees at a similar level?

The 4 possible answers are…



(a) There is a risk of collision, you should maintain heading and speed.

(b) There is no risk of collision.

(c) There is a risk of collision, you should climb or descend.

(d) There is a risk of collision, you should turn right.

The correct answer is (a) However in order to get this answer correct will be somewhat of a guess as there is NO reference to “you should maintain heading and speed.” In the Air Pilot’s manual (Air Law & Meterology



I take it the guys at Pooley’s have made an arse of this question. Or the proof reader was not very good at their job!

Not moving = collision risk.

You see his green light - right wing, he should yield.

Disagreements?

Presumably the other aircraft looking at you will also see a green light on a steady relative bearing and think that you should yield. Which of you seeing exactly the same picture should yield? Near head on both turn right.

The question relates to EU law, not to the Air Pilot's Manual or any other commercial publication. SERA 3210(a) states, "The aircraft that has the right-of-way shall maintain its heading and speed." Thus, in the OP's quoted scenario, answer a. is entirely correct.

The geometry of the question (you don't see his white, the intruder is on your 330 bearing) implies he sees your red. And should give way to it - ain't that the whole magic behind th colour coding?

I agree, this is a right-of-way question where, as the priority traffic, one shall avoid manoeuvring.