Instrument Flight Rules and Air Law
Instrument Flight Rules and Air Law
The NCAA Instrument Rating Theory paper tests the legal framework you fly inside: ICAO Annex 2 rules of the air as adopted in the Nigerian Civil Aviation Regulations (Parts 61 and 91) and procedures published in the Nigerian AIP. Expect clearances, cruising levels, altimeter setting, minima and the privileges and currency limits of the rating - not handling technique.
Core rules
- A clearance is an authorisation with limits. You may deviate only for traffic, terrain/obstacle or an emergency, and must tell ATC as soon as practicable.
- At and above the transition altitude, altimeters are set to standard pressure 1013.25 hPa (QNE) and altitudes become flight levels. Below it, set QNH. The transition level is the lowest usable flight level for the current pressure and is notified by ATC or the AIP.
- IFR cruising levels follow the semicircular rule on magnetic track: 000–179° take odd flight levels, 180–359° take even flight levels.
- An IFR flight needs a destination alternate unless the destination has suitable separate approaches and the weather allows a landing without one; alternate minima are published per aerodrome.
- Rating privileges depend on recent instrument experience (approaches and holding); lapsed currency means a proficiency check before carrying passengers under IFR.
Worked example
Filed track 275°M at FL 300. The track sits in the 180–359° band, so even flight levels apply: FL 300 is correct and FL 290 is not. Once cleared below the transition level the pilot sets QNH locally, and the governing terrain figures become the published MSA/MEA rather than the flight level.
Traps
- Applying the VFR quadrantal rule (odd/even plus 500 ft) to an IFR level.
- Forgetting the transition level changes with QNH - a level usable in the morning can fall below it in the afternoon.
- Treating an airways clearance as permission to descend or to enter another airspace.