Flight visibilities

PPL Training

Flight visibilities

james mosedale 29/07/2003, 7:45 PM
Hi guys,

Getting a little confused on flight visibilities for the basic ppl holder. In uncontrolled airspace can a basic ppl fly in a flight visibility of 1500m below an IAS of 140? Or is this reduction in visibility only available to ppl pilots with an IMC rating?

I believe that the ppl minimum visiblity is 3km and in sight of the surface, in which case i would think that this minimum cannot be reduced. Then i look at the vmc minima and that states that below 3000ft clear of cloud and in sight of the surface at speeds of less than 140 IAS you can fly at 1500m visibility.

Any feedback would be greatfully received.

Many thanks

James

Re: Flight visibilities

Andrew Sinclair 29/07/2003, 8:48 PM
Hi James,

Easy to get confused. What is VMC and what the basic PPL holder weather minima are is very different, try to divorce them from each other.

In open FIR for a fixed wing aircraft at an IAS of 140kts or less VMC conditions are defined as at least 1500m Flight Vis, Clear of Cloud and in Sight of the Surface.

BUT

The minimum flight visibility for a basic PPL holder without IMC or instrument rating is 3km flight visibility and must Stay in Sight of the Srface.

As a result of this you could say that in order to fly in met conditions which are described as VMC, below 3km flight vis. but above 1500m flight vis. for the conditions above and in Class F & G you must hold either and IMC rating (UK and teritories only) or an Instrument Rating (IR)

This looks a very complicated issue and can be at first glance. I recommend you review the Rules of the Air and the Air Navigation Order for further clarification.

Just a brief answer to start but I am sure others will give chapter and verse or I can if you wish.

Re: Flight visibilities

Andrew Sinclair 29/07/2003, 9:17 PM
P.S. Just to confuse the issue and prompt a bit of conversation.....there is nothing wrong with and basic PPL holder without either an IMC rating or and Instrument Rating flying Instrument Flight Rules (IFR) in certain circumstance in weather which is VMC.

In fact to make it a little interesting if the basic PPL has the day only restriction removed from his licence by satisfactory completion of night training, then he must fly IFR if he wishes to fly at night, but he may still have no IMC or Instrument Rating!

Re: Flight visibilities

james mosedale 29/07/2003, 9:59 PM
Thanks Andrew, that was helpful. This is proving to be a little bit of a sticky patch as i have my Air law exam coming up in the next few weeks.

I will centainly be looking into this area a lot deeper than i have already, aswell as annoying my flight instructor.

Thanks again Andrew.

Re: Flight visibilities

Andrew Sinclair 30/07/2003, 8:45 AM
Hi James,

I wrote a long post last night trying to explain the issue, after my first one. It got a little complicated so I decided not to post it because it is a conversation that is better had with your instructor face to face (I am not an instructor!); you rightly point this out in your post. I tried to find a way to put it simply and came up with the following.

Consider driving a car. The law that covers this activity is the Road Traffic Act (as well as other regulations). Now consider the Highway Code, that explains how we should drive, traffic lights, road useage etc etc. Now the ANO is the equivalent of the Road Traffic Act and the Rules of The Air is the equivalent of the Highway Code. There are differences but in principle this is a good analogy.

In the Road Traffic Act it states how we are licenced to drive motor vehicles. Now let's say that UK changed it's road traffic act to say that new drivers could only travel aup to a maximum speed of 50mph for the first 5 years.

We could have a situation where a new driver had a restriction to their licence to travel 50 mph and if they were travelling on a motorway where the national speed limit is 70 mph they still woud only be able to travel 50mph or less. Other drivers who did not have the restriction would be allowed to travel at 70mph or less, but out learner is restricted to 50mph.

Pilots with IMC or IR are allowed to fly in flight vis of x kilometres but PPLs without an instrument qualification are restricted to a higher viz requirements as the learner driver is to a lower speed.

Just for interest, there are many of these issues which at first look complicated when dealt with in isolation, but when the subject is looked at as a whole they become easier to understand. The key, I believe, is to learn the subject as a whole and not just the answers to pass the exams.

They reason I say this is because PPLs may come across many instance where we have to make a judgement call based on your knowledge of aviation law and it is good to have a firm grasp on it. Everytime I hear something I don't understand I go and pull out my ANO or Rules of the Air and dig it out. Most of the time it results in me saying "Well I never did!". A recent example is flying a Single Engine Piston (SEP) across the London City Zone, over the dome. The guys at Thames Radar will happily give you a clearence through there Class D airspace BUT the legality of flying this route is another thing. If the engine quits can you land clear as mentioned in Rule 5? What is the glide range of your aircraft? Is landing in the Thames landing clear? These questions face even the low hours PPLs and good airmanship (and the law) dictates that we know the answers and fly in accordance with all the rules. Sorry to bang on but Air Law, whilst probably not the most enjoyable subject is very important for both a professional and amateur flying career.

Hope it goes well!

Re: Flight visibilities

Norman Braithwaite 30/07/2003, 10:57 AM
I thought I understood, but now I'm not so sure.

I suspect that Andrew's first post gives the answer for Air Law exam purposes.

This is a point that had me very confused. The book (Pratt) had 2 almost identical diagrams showing different Classes of space, and different privileges. It was only when my instructor pointed out that one of them described weather limitations for VMC, and the other described what you could do with a basic PPL. I think the two are the same, apart from this particular point.

Re: Flight visibilities

Andrew Sinclair 30/07/2003, 6:11 PM
Norman,

The thing is that they are not the same in this obvious way, but in other ways they are different too.

Imagine flying along at 3500ft AMSL in Class G airspace. Your track is 300° magnetic. You are trying to keep below cloud because you must keep "In Sight of The Surface" (licence condition). You just begin to clip the bottom of the clouds but that's not a problem. Well in theory, yes it is because you believe you are flying VFR, but you cannot be because to fly VFR you must be in VMC. Above 3000ft AMSL you must be 1000ft vertically and 1500m from cloud to be is VMC. So ok never mind you are not in VMC but within your licence conditions (there are no seperation minima from cloud for standard PPL above 3000ft for Class G just a 3km min viz minima) so that's ok. So what rules are you flying under if not VFR then maybe IFR. The trouble here is that above the transition altitude you must adhere to the quandrantal rule and at the track you are flying you should be at an even flight level +500' (e.g. FL45, FL65, FL85). So you could descend below 3000ft and perhaps fly at FL25. This FL would be recommended but not mandatory as it would above the transition altitude.

Just a scenario which is possible and sort of demonstrates that a knowledge of the whole subject is perhaps a good thing to make good judgement calls when flying along. I must admit I don't have this total knowledge by a long way, but like most folk somewhere up the learning curve.

Cheers

Andy

Re: Flight visibilities

james mosedale 30/07/2003, 11:25 PM
Thanks Andrew,

Your feedback has been very informative and helpful. Where do you fly, how long have you been flying, what aircraft do you fly. I am currently 14 hours into my ppl and have done 50mins solo. Its the best thing i have ever done. i am currently 23 years old and i am seriously considering a career in aviation. Any words of advice??

Re: Flight visibilities

Andrew Sinclair 31/07/2003, 9:46 AM
Hi James,

I am just a low hours PPL (110 hours total time). I passed my PPL a couple of years ago or so and now have a ownership share in a C172 and fly from Redhill and Biggin Hill where the aircraft is hangered.

I do not consider myself to be qualified to give any advice really. I was told by my examiner during my skill test de-brief that the PPL was a licence to learn and his words stayed with me so I have been looking into much more detail at all the requirements, rules and legislation along with AIP/AIC/LARSOR and JAR documentation and it dawned on me how little I knew and how far down the learning curve I was! With this as a backdrop I have been trying to learn and gain experience as I go along, in a way to fill the bucket of experience before I empty the bucket of luck! I have met some excellent pilots, instructors and engineers along the way all of whom have been really happy to inpart knowledge and experience.

As far as a career in aviation I would recommend that you look at this website, www.pprune.org. It is a web site with a dedicated forum for asking questions about professional flying. You will find most of the answer there or if not register and ask and the respond will come pretty quickly.