Topical Issues

More detail on topical aviation issues.

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  Non-directional beacons (NDBs)
Solar Flares Aerobatics Rules
Wire Marking in New Zealand Military Operating Areas

Non-directional beacons (NDBs)

12 March 2012

Non-directional beacons (NDBs) have been in place in New Zealand since about World War II, and the aircraft componentry similar to that in use today became available for civil use in the 1950s. NDB and the aircraft component, known as Automatic Direction Finder (ADF), is a relatively inexpensive navigational aid, and although it is not the preferred primary means of air navigation these days, it is still widely in use.

There are currently some 32 NDBs in operation in New Zealand, but they are being progressively retired from service with replacement by more modern and highly accurate technologies.

NDBs radiate a radio signal on a particular frequency. The aircraft’s ADF equipment tunes into that frequency and a needle on an instrument points toward it – like a compass needle points to the magnetic North Pole.

NDB transmission is continuous and weakens and widens with distance, like a ripple on a pond when a stone is thrown in.

NDB approaches are checked for fly-ability, signal and coverage. As well as being inherently non-precision, NDB signals may vary according to atmospheric conditions and environmental factors, such as increased ionisation at night, interference, mountainous terrain, thunderstorms, coastline refraction and the altitude of the aircraft. Tuning errors on board the aircraft can also affect accuracy. Pilots learning to fly on instruments are trained to expect these variances, and NDB approaches are always designed with large safety margins of both distance and height around them.

Solar Flares

25 Jan 2012

The solar flares being experienced this week are not expected to have any significant impact on aviation in New Zealand. At most, they might cause intermittent HF (long-range) radio noise or outages, but this is an expected part of normal operations. Aircraft have other communications systems, such as VHF radio and satellite communications. Solar flares are unlikely to affect any other systems on aircraft.

If satellites were compromised, this is unlikely to affect airliners. Although GPS is used in navigation, aircraft carry alternate means of navigation such as ground-based navigation aids in domestic airspace. In oceanic airspace, transport aircraft will be able to use the inertial navigations systems they are all fitted with.

Should an unprecedented problem occur, pilots would be warned via the usual notification through the NOTAM system.

Aerobatics Rules

25 Jan 2012

A recent aircraft accident has raised general enquiries about the rules covering aerobatics.

Pilots must hold a specialist aerobatic rating to carry out aerobatics below 3000 feet. Pilots cannot carry passengers unless they hold this rating, and passengers cannot be carried on aerobatic flights below 3000 feet.

Achieving an Aerobatic Flight Rating involves a ground course, special flight instruction and competency checks every two years. Once a pilot holds an aerobatic rating, they may fly aerobatics solo as low as 1500 feet if they have been endorsed to do so. To fly lower than 1500 feet, the pilot must hold an additional low level authorisation, which allows the pilot to fly lower provided they are flying in, or practicing for, an aviation event.

Not all aircraft are suitable for aerobatics.

Wire Marking in New Zealand

Example of wire marker balls at Manapouri Power Station, Fiordland

Example of wire marker balls at Manapouri Power Station, Fiordland

See larger image (png file)

12 Jan 2012

Small wires are not required to be marked in New Zealand. The minimum height for flight in most areas is 500 feet above ground level, unless there is a bona fide purpose, such as takeoff and landing.

There are strict wire marking standards for the takeoff and landing areas at aerodromes, and New Zealand meets all internationally-prescribed standards.

In aerodromes and all other areas, objects including masts and wires that are higher than 60 m must be notified to the CAA. High tension powerlines and other hazards are marked on the navigation charts used by pilots.

The possibility of marking some identified high-risk wires is under consideration and detail can be viewed on the CAA web site. It must be stressed though, that this material does not refer to the type of low level wire involved in the recent fatal accident near Carterton.

Military Operating Areas

Aeronautical Chart showing MOA 106

Aeronautical Chart showing MOA 106

See larger image (jpeg 286 KB)

01 Dec 2011

The November/December 2011 CAA Vector magazine talks about an event this year in which a light aircraft entered restricted airspace that was being used by a military aircraft to practise bombing runs.

Read Vector article (PDF 558 KB)

This image shows how Military Operating Area 106 is marked on the aeronautical charts that pilots use.

The multi-sided red box shows the outline of the area, and the red circle in the middle is a smaller MOA (number 103). MOAs are active only when activated by NOTAM (Notices to Airmen). A NOTAM will say something like “MOA 106, active from 1000-1200, 30/11/2011”. That means that from 1000 til 1200 the MOA is a restricted area, and aircraft can enter only if they have the permission of the ‘administering authority’. The rest of the time, aircraft can transit through this area below 4500 feet unrestricted. Administering authorities for each piece of restricted airspace are listed in the Aeronautical Information Publication New Zealand, available free online. See  Military Operating Areas (PDF).

This event highlights how important it is for pilots to ensure they request NOTAMs as part of their pre-flight preparation. This can be done free either online at the Internet Flight Information Service IFIS, or by calling the National Briefing Office (also free).

You can learn more about MOAs in the CAA Good Aviation Practice  booklet, New Zealand Airspace (PDF 1.6 MB).

Looking at the past five years, the CAA has records of four occasions this year when aircraft have busted the airspace of an active MOA, eight occasions in 2010, two occasions in 2009, three in 2008 and four in 2006. Most of these have happened in the MOAs around Ohakea.