SNAP Checks

When preparing to conduct an instrument approach, it is imparitive that the pilot be able to encorporate into the pre-approach preparation a efficient, thorough and effective preparation actions that cover all cockpit sequences that must be completed by the pilot before flying the instrument approach procedure leading to a landing or missed approach.  The SNAP Checks are the IFR equivalent to the GUMP Checks in the Multi-engine Class Rating training.


Speed.  Make sure the aircraft is established at the proper speed for conducting an approach—the pace of the approach in most cases is controlled by the pilot, but this is not always the case—in the case of vectored approaches, for example, the pace if events is commonly set by the controller through speed restrictions.  

A rule of thumb is to set the power to the same power setting used during holds—120 KTS (138 MPH).  The power should be therefore set to 18"Hg Manifold Pressure (MP).

Because altitude loss is commonly associated with pre-approach preparation, it is a good idea not to extend flaps in most cases as you are likely not to want to include during your workload the need to monitor a flap extension speed limit during the descent.  Also, during vectored approach, it is easy to get behind the controller's planned descent profile and the ability to produce a prolong agressive nose-down descent attitutde is important if catch-up is required.

As you will see, speed restrictions by Victoria Airport terminal controllers are common, and it is something that you simply have to get used to.  If a speed restriction is set by the controller as a condition to an approach clearance, the maximum speed that you should except is 120 KTS (138 MPH)—anything faster than this will compromise safety by making the landing zone of the runway difficult to target, despite the long runway.

If the approach you are managing leads to a confined runway of, for example, less that 4000', for example, speed control becomes more critical and the deployment of flaps for better pilot control of the descent profile should be consider.  Speed control should be establish with a power setting of 18"Hg MP.

Remember, of course, that manifold pressure increases 1"Hg per 1000' descent, for prolonged descent during the procedure turn will required MP monitoring and periodic reductions to maintain the 17" or 18" MP target.


Navigation Aids.  Make sure that all the navigation aids required for the approach and missed approach procedure are properly tuned, identified, tested (if necessary), and selected.2  The required settings will be indicated from the approach plate.


Approach Plate Briefing.  This is a ritualistic but careful review of the approach procedure, and typically includes a sequential review of the information contained on the approach plate.  This should be automatic, rehersed, and committed to memory.  It should not occupy and cerebral cortex time and energy, but should be instead and well-practice automated response that does not require the eyes to leave the instrument panel.

For more information on this, go to Approach Plate Briefings.


Pre-landing checklist.  this fits in the same category as the approach plate brieifing.  It should be an automated response that is completed accurately and effeciently and—most importantly—does not require the eyes to divert from the instrument panel.  The pre-landing checklist (yellow card tucked on the left side of the glareshield) must be pulled and read to backup the memory items, but this is just a silent review by the pilot and must not be a repeat of the complete pre-landing checks.  During training, say "Pre-landing Checks completed" for the benefit of your Instructor and the Examiner.