Night Wings Endorsement – NR

The Achievement Scheme is run by the MFNZ as a National Scheme, and it is open to all model flyers.

The Night Rating certificate is a supplementary type, meaning the candidate has already successfully passed as a minimum the Basic test for their respective model.  It is applicable to any model.

Completion of this endorsement is the basic qualification for enabling Night Flight in accordance with the MFNZ CAR102 Operation Manual.

The candidate must successfully complete the test schedules in one attempt. A maximum of two attempts at the examination are permitted in any one day.

As the Night Rating certificate is a supplementary type covering many disciplines of model the test routines are to be carried out in accordance with the relevant Basic category test for the model being tested, however carried out with the candidate flying the routine between the hours of ECT and MCT, in a shielded environment if possible.

Flying at night may seem to relatively trivial, however there are a number of physiological features of human vision, as well as regulatory and safety requirements that need to be addressed.

Model Flying New Zealand’s CAR102 Unmanned Aircraft Operations Manual allows for flying at night, beyond the CAR101 requirement of only flying at night when shielded. Pilots must hold Night Wings to be compliant. Please refer to Chapter 8.6 of the MFNZ CAR102 manual.

When is night?

It might seem straight forwards, night is when its dark?!

In Aviation, night is between the hours of Evening Civil Twilight (ECT) and Morning Civil Twilight (MCT), these times change around the country and time of the year and are provided in the AIP Daylight Tables (GEN 2.7) – https://www.aip.net.nz/assets/AIP/General-GEN/2-TABLES-AND-CODES/GEN_2.7.pdf

To use the Daylight Tables, find the zone you will be be in, then in the table find the closest date. This first number is Morning Civil Twilight, the second is Evening Civil Twilight.

As an example, let’s say we are after MCT and ECT for Christchurch (Zone 6) on February the 6^th.

We locate February the 7^th, being closest to the 6^th, and Zone 6. Morning Civil Twilight is 1714, Evening Civil Twilight is 0823. This appears wrong (for a reason!), the standard clock used in Aviation is called UTC, or Universal Coordinated Time, which is either +12 hours in New Zealand Standard Time (NZST), or +13 hours in New Zealand Daylight Time (NZDT)

In our above example, February 6^th is in NZ Daylight Time, or daylight savings. To convert it to local time we add 1300.

1714+1300 = 3014

3014 is obviously a strange time, what has happened is we have gone around the clock, New Zealand is ahead of UTC time. So, Feb 6^th in UTC time has become Feb 7^th in NZ Daylight time. To correct this, we take 2400 away.

3014-2400 = 0614

6:14am in the morning (on the 7^th) is Morning Civil Twilight. 6:13am is legally Night, 6:15am is legally Day.

To convert ECT, the same process is used.

0823+1300 = 2123

So 9:23pm is Evening Civil Twilight. 9:22pm is Day, 9:24pm is Night.

Human vision at night

The sensing cells in the back of our eye, making up the retina, are referred to as Cones and Rods.

Cones are our HD sense, they have amazing visual accuracy, can resolve things in great detail and in colour, however they require a reasonable amount of light to be effective, without reasonable amounts of light… they are next to useless. Cones are stacked up around the centre of the back of the eye and provide much of our normal vision when we look directly at a scene in good lighting.

Rods are our primitive vision and are spread much further around the back of the retina. Rods work relatively well in low light, however, are poor at resolving detail or clarity and see in grey scale. Due to the location of the Rods in the eye, they are purely in our peripheral vision. They exist to allow us to spot predators in the night!

What this means for flying at night is that where we normally look, directly in front of us, to fly is not ideal and at night better vision is had by not directly looking at the model and instead looking at is slightly to the side!

Dark Adaptation

The time it takes for your eyes to adapt to the dark, or for when your eyes transition from Cones to Rods, is referred to as as Dark Adaptation. It takes approximately 20 minutes to achieve 80% of your maximum possible night vision performance, and a further 10 minutes to achieve full night vision. Exposing your eyes to light near instantaneously resets the process! To ensure you have the best possible night vision, give yourself 20 minutes to adapt, and then avoid bright lights afterwards.