DASR 3/1994 - Instructions

V.F.R. (Visual Flight Rules). The instrument does not define V.F.R. but relies on the existing meaning under the Civil Aviation Regulations: flight conducted in visual meteorological conditions with prescribed visibility and cloud clearance minima. The instrument prescribes navigation requirements that apply only to V.F.R. flights, not to I.F.R. operations.

Positive position fix. Defined implicitly in Part 1 as a fix obtained by using a non-directional beacon, VOR, DME, or the intersection of two or more position lines from radio navigation aids crossing at 45° or more. A fix must be “positive,” meaning the pilot must be able to confirm the aircraft’s exact location within the tolerances of the aid. The instrument does not allow approximations or DR (dead reckoning) alone as a fix.

Rated coverage. The geographic area within which a radio navigation aid provides a signal of sufficient strength and accuracy for navigation. Part 1 requires that any position line used for a fix must be within the rated coverage of the aid (except when using only NDBs, where the fix must be within 30 miles of each beacon). This concept is critical for route planning: a pilot cannot rely on an aid outside its published coverage.

Self-contained navigation system and long-range radio navigation system. These terms are used in clause 2.1(4) but are not defined in the instrument. In practice, a self-contained system means a system that does not rely on external signals, such as an inertial navigation system (INS) or a doppler radar. A long-range radio navigation system would include systems like LORAN or Omega (now largely superseded by GNSS). The instrument permits these as alternatives to a licensed flight navigator when not navigating visually, but subjects them to additional constraints. Notably, clause 2.1(5) imposes a specific tracking error allowance of +/-9.5° when using a radio navigation system under paragraph (4)(d), which would apply to many GNSS-based systems if they are classified as radio navigation systems rather than self-contained.

Controlled airspace. Referred to in Part 3 but not defined. It takes its meaning from the airspace classifications under the Airspace Regulations or the relevant AIP. The instrument imposes stricter track keeping obligations in controlled airspace: immediate correction of deviation, no deviation without ATC clearance (except emergency), and mandatory notification of ATC when off-track by prescribed deviations.

Tolerances. Part 3 uses the word “tolerance” to describe the distance or angular margins a pilot must apply to ensure the flight path does not infringe controlled airspace or restricted areas. These are not navigational accuracy requirements but safety buffers. For radio navigation aids outside controlled airspace, the instrument provides fixed angular tolerances: +/-6.9° for NDB, +/-5.2° for VOR and TACAN, +/-12° for dead reckoning. For visual navigation, distances vary by height above mean sea level (for high-altitude VFR) and height above ground level (for low-altitude VFR), with separate tables for powered aircraft during daylight and at night. Gliders get a special +/-5 mile tolerance below 10,000 feet AGL. If using area navigation (RNAV), a flat +/-14 mile tolerance applies.

Track guidance and order of precision. Clause 3.1(1) requires that when radio navigation aids are the primary means of navigation, the pilot must use the aid that provides the most precise track guidance and must use only aids that define the relevant track. The instrument ranks aids from most to least precise: localiser, VOR, NDB, locator. This hierarchy matters for track keeping (e.g., a pilot must not use an NDB to track a radial when a VOR is available on the same route) and also for determining off-track deviation thresholds under clause 3.2.

PAN call. A radio telephony urgency signal (not distress) used to indicate that the pilot has a need to divert and is out of radio contact with ATC. The instrument requires that the details of the diversion be broadcast on appropriate frequencies. This differs from a MAYDAY which signals distress.

The instrument directly binds the pilot in command of any Australian-registered aircraft (or any aircraft operating in Australian airspace, by extension of the Civil Aviation Regulations) that is conducting a V.F.R. flight and navigating by radio navigation equipment or by any of the alternative means listed. It does not apply to I.F.R. flights or to V.F.R. flights that are navigated solely by visual reference and remain within the 30-minute fix interval. However, even visual navigation is subject to the 30-minute fix interval requirement (clause 2.1(3)) and the tolerances for avoiding controlled airspace (clause 3.3). The practical effect is that any pilot flying V.F.R. in controlled airspace, at night, above cloud, or near controlled airspace boundaries is affected.

The instrument imposes additional burdens on flight navigators. Clause 2.1(4)(c) allows the aircraft to be navigated by a “full time licensed flight navigator” as an alternative to visual reference or self-contained/radio systems. This is a costly option and typically only employed on larger aircraft; for most general aviation pilots, it is not viable. The instrument implicitly encourages pilots to use either visual reference (which restricts them to 30 minute fixes and forbids flight at heights above 2000 feet if not using visual reference) or to invest in self-contained navigation systems or long-range radio navigation systems. The RNAV tolerance of +/-14 miles (clause 3.3(5)) is notably larger than the tolerances for specific aids, which may be a trap for pilots who assume RNAV gives better containment.

The instrument also affects air traffic control providers. Controllers must expect pilots to self-report off-track deviations under clause 3.2(2) and to request clearance for any track deviation in controlled airspace. The PAN call requirement under clause 3.2(3) places an obligation on the pilot to broadcast on appropriate frequencies, but ATC must be monitoring those frequencies. The instrument does not specify ATC’s obligations, but it imposes a compliance burden on pilots that indirectly shapes controller workload.

Private and recreational pilots are the most affected group. They must ensure they are qualified to use the navigation aids they intend to use (clause 2.3 requires the pilot to indicate in the flight notification which aids he or she is qualified to use). This imposes a knowledge and currency burden. The instrument does not specify how qualification is demonstrated; that is left to the licensing regulations. For a pilot using a handheld GPS as a primary navigation aid, the instrument may classify that GPS as a radio navigation system if it uses satellite signals, or as a self-contained system if it is inertial. The ambiguity imposes legal risk.

Charter and commercial V.F.R. operators face additional costs: the need for dual navigation aids, flight planning to ensure positive fixes are achievable within two hours, and potentially the need to employ a navigator on longer overwater flights where visual reference is impossible. The requirement that a radio navigation system can only be used on routes where the aircraft will come within rated coverage after a fix plus 9.5° error (clause 2.1(5)(a)) eliminates any route that lacks a suitably sited aid along the track. This can constrain route choices and increase fuel costs.

Duty to obtain positive position fixes. The pilot must obtain a positive position fix in accordance with Part 1 if navigating by radio navigation equipment under V.F.R. The fix must be by one of the four methods in clause 1.1(1). If using only NDBs, the fix must be within 30 miles of each beacon (clause 1.1(3)). This duty is refreshed by interval requirements elsewhere: under clause 2.1(5)(b), the maximum interval between fixes is two hours when using a radio navigation system; under clause 2.1(3), if navigating visually, fixes at intervals of not less than 30 minutes. The use of “not less than” means the pilot must fix at least that often, but can fix more frequently.

Duty to navigate by visual reference below 2000 feet. Clause 2.1(2) is absolute: at 2000 feet or less above ground or water, the pilot must navigate by visual reference to the ground or water. This overrides any permission to use a radio navigation system under clause 2.1(4). Only aircraft that are operating at a height of more than 2000 feet may use alternative means. This is a significant restriction: a V.F.R. pilot flying at 2000 feet or lower cannot rely on a GPS to position the aircraft; he or she must look outside.

Duty to use qualified aids. Clause 3.1(1) requires that the pilot use only aids which he or she is qualified to use. The instrument does not define qualification; it is likely determined by the pilot’s licence endorsements or training. The pilot must also use the aid that provides the most precise track guidance. This imposes a hierarchy obligation: if a VOR and an NDB both define the same track, the pilot must use the VOR.

Duty to maintain track and notify ATC. In controlled airspace, the pilot must immediately take action to regain track if a deviation is noted (clause 3.1(3)). Clause 3.2(1) forbids deviation from track without ATC clearance except in an emergency. The pilot must notify ATC if the aircraft is off-track by the specific deviations listed in clause 3.2(2) (e.g., half-scale CDI for localiser/VOR). If out of radio contact and needing to divert, the pilot must issue a PAN call (clause 3.2(3)). This duty is onerous because it requires continuous monitoring of deviation and immediate communication.

Duty to apply tolerances outside controlled airspace. Clause 3.3(1) mandates that the pilot apply the applicable tolerances to the flight path to ensure controlled airspace or a restricted area is not infringed. The pilot must calculate the track with the tolerance added to the aircraft’s intended path. This is not a mere recommendation; it is a requirement to keep the aircraft physically outside the boundaries after accounting for the tolerance. The pilot bears the risk of being inside the controlled airspace if the tolerance is not applied.

Right to use visual navigation or radio navigation systems. The instrument permits the pilot to choose between visual reference (with the 30-minute fix interval and the 2000 feet limitation) and one of the four alternative means in clause 2.1(4). That is a menu of rights, not a single right. The pilot also has the right to change navigation methods mid-flight, provided the applicable constraints are respected (e.g., cannot descend below 2000 feet while using radio navigation only; must revert to visual).

Right to deviate in emergency. Clause 3.2(1) specifically exempts emergencies from the need for ATC clearance. This is consistent with general aviation law but is explicitly stated. The pilot must still, if out of radio contact, issue a PAN call.

The instrument itself does not prescribe any penalties. It is made under regulation 174D of the Civil Aviation Regulations, which is part of a regulatory framework where breaches of instructions issued under that regulation are treated as breaches of the Regulations. Consequently, the penalties are found in the Civil Aviation Act 1988 and the Civil Aviation Regulations (now largely replaced by the Civil Aviation Safety Regulations 1998, but the instrument may still be in force subject to transitional provisions). A breach of a mandatory requirement (e.g., failing to obtain a positive position fix at the required intervals) is likely to be an offence under regulation 287 of the Civil Aviation Regulations (if still applicable) or under the equivalent provision in CASR 1998. Maximum penalties can include fines for individuals (often up to 50 penalty units for strict liability offences, or higher for fault based offences) and suspension or cancellation of licences, certificates of approval, or air operator certificates.

Enforcement is by the Civil Aviation Safety Authority (CASA). The instrument being from 1994 predates CASA’s creation (which occurred in 1995), but enforcement powers now reside with CASA. The practical enforcement risk is highest in two areas: (1) an incident involving a near infringement of controlled airspace that triggers an investigation; (2) a pilot who is unable to demonstrate compliance with the position fix requirements after an accident or occurrence. Because the instrument imposes detailed technical obligations (e.g., the +/-9.5° tracking error allowance in clause 2.1(5)(a)), a pilot who cannot show that the route was capable of meeting that requirement may be found non compliant even if no incident occurred.

There is no statutory defence of reasonable mistake or due diligence in the instrument itself; those defences may exist under the general criminal law or under the Act. Strict liability may apply to some elements (e.g., failing to obtain a fix at the required interval) but not to others that require knowledge (e.g., clause 3.2(2) requires that the pilot “find” the aircraft off-track; if the pilot did not detect the deviation, there may be no breach of the notification duty, but the duty to regain track under 3.1(3) applies once the deviation is noticed). This asymmetry could create a trap: the pilot who fails to notice an off-track condition avoids the notification duty but still breaches the track keeping duty under 3.1(3) if he or she “notices” - constructive notice might be imputed if a reasonable pilot would have noticed.

The instrument is subordinate to the Civil Aviation Act 1988 and the Civil Aviation Regulations (as in force on 6 January 1994). It does not repeal or amend any other instruments. It must be read together with the general V.F.R. flight rules in the Regulations, which cover visibility minima, cloud clearance, and aircraft equipment requirements. The instrument supplements those rules by adding navigation specific instructions. If there is a conflict, the instrument being an instruction under regulation 174D likely prevails over the general regulations to the extent of any inconsistency, but the instrument does not contain a supremacy clause.

The instrument interacts with the airspace classification system administered by Airservices Australia and set out in the Airspace Regulations (now the Airspace (Designation etc) Regulations). The tolerances in Part 3 are designed to avoid infringing controlled airspace or restricted areas. That means a pilot must know the boundaries of controlled airspace along the route and apply the tolerances to ensure the aircraft remains outside. The instrument does not define “controlled airspace” or “restricted area”; those definitions come from the airspace regulations.

The instrument also interacts with the Standards and Recommended Practices of the International Civil Aviation Organization (ICAO) annexed to the Chicago Convention. Australia gives effect to ICAO Annex 2 (Rules of the Air) through its regulations. The instrument’s requirements for position fixing, ra dio navigation aid use, and track keeping are consistent with ICAO procedures for VFR navigation, but the instrument imposes specific Australian tolerances (e.g., the 9.5° error allowance) which may differ from other states’ requirements.

The instrument’s requirement that the pilot indicate in the flight notification the radio navigation aids with which the aircraft is equipped and which the pilot is qualified to use (clause 2.3) interacts with the air traffic services flight notification system under the Civil Aviation Regulations. A failure to properly notify could both breach that regulation and create an issue under clause 2.3 itself. The flight notification must be filed with Airservices Australia or as required by the operator’s procedures.

For aircraft operating V.F.R. on top of cloud (clause 2.2), the instrument interacts with the V.M.C. minima and cloud clearance rules. Even if the navigation requirements are met, the pilot must also ensure that the entire flight (including descent and landing) can be conducted in V.M.C. This may require the pilot to obtain meteorological information that the instrument does not mandate, but which is required by other regulations.

The instrument does not incorporate by reference any Australian standards or technical specifications. It uses terms like “non-directional beacon,” “VHF omni-directional radio range,” and “distance measuring equipment” without defining them; those definitions come from the Regulations and from ICAO Annex 10 (Aeronautical Telecommunications). The pilot bears the risk of understanding what constitutes a compliant aid.

The source text shows DASR 3/1994 as an original instrument signed on 6 January 1994. There is no indication of any amendments within the text provided. It is not uncommon for such instruments to remain unamended for decades, particularly when they are anachronistic. The instrument uses terminology and concepts that pre date the widespread use of GNSS (Global Navigation Satellite Systems) such as GPS, which became fully operational in the mid 1990s. The instrument does not mention satellite navigation at all, except possibly the mention of “self-contained navigation system” which could encompass GNSS, but the tracking error allowance of +/-9.5° in clause 2.1(5)(a) is more associated with earlier VOR/NDB based navigation. A pilot using modern GPS might have a much smaller tracking error, but the instrument still requires the pilot to allow for 9.5° per the wording “allowing for possible tracking errors of +/-9.5° from that fix”. That is a specific figure that cannot be lowered by using more accurate equipment. The instrument has not been updated to reflect the decommissioning of many NDBs in Australia or the introduction of GNSS based area navigation.

The user provided only the instrument; there is no amendment history in the source. It is possible that the instrument has been later repealed or replaced by a CASR instrument (e.g., CAAP 234 1(0) or a Manual of Standards), but that is not contained in the source. The analysis must treat the instrument as currently in force as presented. Given the age and the lack of amendment, it is plausible that the instrument is no longer in active use by CASA and may have been superseded by advisory circulars or other instruments, but that is speculation not grounded in the source. The trustworthy conclusion is that the instrument appears in its original form, dated 1994, without any amendments shown. Compliance professionals should verify with the Federal Register of Legislation (FROL) whether it has been repealed or varied.

The source text contains no references to any court or tribunal decisions. This instrument is highly technical and prescriptive; it would rarely be litigated on its own terms. Most enforcement actions would be under the broad provisions of the Civil Aviation Act (e.g., operating an aircraft in a manner that causes a hazard) rather than for a specific breach of clause 2.1(5)(a). The instrument’s requirements could, however, be raised in a civil action for negligence (e.g., after an airspace infringement or collision) where the conduct of the pilot is measured against the instructions. For instance, if a pilot failed to apply the tolerance in clause 3.3 and entered controlled airspace without clearance, that breach could be evidence of negligence. Similarly, a failure to obtain positive fixes at the required intervals could be used to demonstrate a departure from prudent practice.

Given the age of the instrument, there may have been administrative decisions by CASA regarding licence suspension or cancellation that refer to breaches of this instrument, but CASA’s internal review tribunal decisions are not published in the source. The Freedom of Information Act may allow access, but no cases are cited. It is notable that the instrument uses the term “positive position fix” without defining what constitutes a valid fix (e.g., does a GPS coordinate with RAIM count?). This ambiguity could lead to disagreements between pilots and regulators, but without litigation history it is unclear how the term has been interpreted. The prudent practitioner must assume the instrument is enforced strictly according to its literal terms until a court rules otherwise.

The 30 minute rule for visual navigation. Clause 2.1(3) says the pilot must positively fix the aircraft’s position by reference to topographical features at intervals of not less than 30 minutes. This does not mean the pilot can simply look out the window; the fix must be “positive” , a precise identification of a feature on a chart. In practice, a pilot flying over featureless terrain or at night with poor visibility may not be able to obtain a positive fix visually. If the pilot cannot, he or she must either climb above 2000 feet and use a radio navigation system (subject to the requirements of clause 2.1(4) and (5)) or remain below 2000 feet and accept the risk of non compliance. This is a trap for pilots who assume visual reference automatically satisfies the 30 minute rule.

The 2000 feet cliff. Clause 2.1(2) is absolute: at 2000 feet or less, the pilot must navigate by visual reference. A pilot cannot use a GPS or VOR as the primary navigation method at that height, even if the GPS is highly accurate. This creates a practical problem for a pilot flying V.F.R. at 2000 feet in haze; he or she may feel safer using GPS but is legally required to use visual reference. Similarly, a pilot who uses a radio navigation system for situational awareness below 2000 feet may still be in breach because the instrument mandates the primary method. The instrument does not forbid secondary use of radio aids, but the wording “must navigate the aircraft” (clause 2.1(2)) suggests that the visual method must be the primary basis of navigation.

The tracking error allowance of +/-9.5°. Clause 2.1(5)(a) is the most onerous and easily overlooked requirement. When using a radio navigation system under clause 2.1(4)(d) (which includes GPS if classified as a radio navigation system), the route must be such that after a positive fix and allowing for a tracking error of +/-9.5°, the aircraft will come within rated coverage of a radio aid. The 9.5° is a fixed error; it is not a function of the system’s actual accuracy. A modern GNSS system may achieve much better than 9.5°, but the instrument does not permit the pilot to use a smaller allowance. This means that on many routes, the pilot must ensure that the first fix is within a narrow cone of the next aid’s coverage, which may be impossible if the coverage is patchy.

The PAN call requirement. Clause 3.2(3) requires a PAN call when the pilot is out of radio contact with ATC and considers it necessary to divert from the cleared track. The instrument does not define “out of radio contact.” It could mean that the pilot cannot establish communication after reasonable attempts, or that the pilot has not been in contact for a period of time. The pilot must also issue the PAN call “on the appropriate frequencies” - plural, which suggests that a single frequency may not suffice. This could be problematic in remote areas with only one VHF frequency.

Tolerances for visual navigation at night. The table in clause 3.3(4) for powered aircraft at night gives tolerances that are twice those for daylight at the same altitudes (e.g., +/-2 miles vs +/-1 mile at 0-2000 feet AGL). A pilot flying at night must be aware that the safety buffer is larger, and must plan the flight path accordingly to stay well clear of controlled airspace. Failure to apply the correct tolerance could result in an unintentional infringement.

The rated coverage requirement. Clause 1.1(2) says a position line must be within the rated coverage of the aid. This is a technical term that may not be readily known to private pilots. The rated coverage is published in the Aeronautical Information Publication (AIP) or in the instrument procedure charts. A pilot cannot use an aid if the aircraft is beyond its rated coverage even if the signal is audible. This is particularly dangerous with NDBs at night, when signal propagation can be greater than the rated coverage and the pilot may receive a false sense of security.

Compliance requires systematic flight planning and continuous in flight monitoring. Before the flight, the pilot must determine the navigation method to be used. If the flight will be below 2000 feet AGL at any point, the pilot must be able to navigate by visual reference for that portion. That means the pilot must have a current chart, be able to identify topographical features, and must plan to obtain a positive fix at least every 30 minutes. The flight route should be chosen so that visual fixes are possible at those intervals; over water or featureless terrain, the pilot may need to climb above 2000 feet and use a radio navigation system.

If using a radio navigation system or self-contained system under clause 2.1(4), the pilot must ensure the route can comply with clause 2.1(5). Specifically, the pilot must identify a radio aid whose rated coverage can be reached after a positive fix, allowing for a 9.5° error on each side of the fix. This is best done by drawing a cone of uncertainty from the fix point and checking whether the rated coverage of the next aid lies within that cone. The maximum time between fixes must be two hours, so the pilot must ensure that aids are spaced along the route at intervals that allow a fix within that time. If the route cannot satisfy this, the pilot must either carry a licensed flight navigator (impractical for most) or change the route to ensure intermediate fixes are possible.

The pilot must also ensure that the aircraft is equipped with the aids that will be used, and that the pilot is qualified to use them. The flight notification must list those aids. This is often forgotten; many pilots file a generic flight notification without specifying the navigation aids. The instrument effectively makes that a regulatory requirement. The pilot should also consider that qualification to use an aid is not the same as having the aid installed; both are required.

In flight, the pilot must obtain positive fixes at the required intervals. For visual navigation, a positive fix by reference to topographical features means the pilot must positively identify a feature on the chart (e.g., a town, road intersection, lake) and confirm the aircraft’s position. A mere “I think we are near X” is not enough. The fix should be recorded (e.g., in the pilot’s log or on the chart) to demonstrate compliance. For radio navigation, the fix must be obtained by one of the four methods in clause 1.1(1). The pilot should note the time and the means used.

Track keeping requires continuous monitoring. If in controlled airspace, the pilot must immediately correct any deviation (clause 3.1(3)) and must not deviate without ATC clearance. If the aircraft deviates by the thresholds in clause 3.2(2), the pilot must notify ATC immediately, even if the deviation is being corrected. This puts a premium on maintaining a precise track. The pilot should set up the navigation aid to the most precise mode appropriate (localiser if available, then VOR, then NDB). The order of precision is mandatory.

Outside controlled airspace, the pilot must apply the tolerances from the tables in clause 3.3 to ensure the flight path does not infringe controlled airspace. For visual navigation at low level, the pilot must know the aircraft’s height above ground level (not just altitude above mean sea level) to select the correct tolerance. This requires accurate altimetry and knowledge of the terrain elevation. The tolerance must be added by the pilot to the intended track; the aircraft must not pass within that distance of the boundary. For example, a powered aircraft flying at 3000 feet AGL during daylight has a tolerance of +/-2 miles; the pilot must keep the aircraft at least 2 miles away from the boundary of controlled airspace (plus any additional margin for the aircraft’s actual position uncertainty). The instrument does not explicitly say that the tolerance is added to both sides; but logically, the pilot must apply the tolerance to the side nearest the controlled airspace. The safest approach is to assume the boundary is 2 miles closer than its charted position.

If the pilot needs to divert due to weather or fuel, and is out of radio contact with ATC, a PAN call must be made on appropriate frequencies (clause 3.2(3)). The pilot should monitor the ATC frequency and also the area frequency; if unable to raise ATC, broadcast the PAN details and the diversion intentions. The pilot should then navigate according to the applicable tolerances even after the diversion.

Finally, the pilot should document the flight planning and fix logs, because if an incident occurs, CASA will likely ask for evidence of compliance. A simple GPS track log may not satisfy the requirement for a positive fix; the pilot should note the time, fix source, and the method used. For flights where visual reference is used, a written or mental record of each 30 minute fix is prudent. The instrument does not require written records, but without them the pilot cannot prove compliance.