Thursday, April 18, 2013

How to brief an approach

A common skill for pilots that is likely to be tested on an interview is how to brief an instrument approach. Briefing an approach is the art of confirming the details of an approach with your fellow pilot without overwhelming him with irrelevant information. There is an abundance of information on an approach plate, some of which is vital to the safety of the flight and some of which does not apply at all.

A sample approach plate is the ILS 35R for Centennial Airport in Denver found nearby. Most companies and airlines use Jeppesen approach plates similar to the one depicted here, however military pilots and some general aviation pilots might be more familiar with approach plates published by the FAA. These are also called “NOS charts” because they were once published by the National Ocean Service. NOS charts are public domain and can be found online at no charge on sites such as A NOS chart has been included for reference, but most interview briefs will be conducted with Jeppesen plates.

Ideally the approach should be briefed while the airplane is in cruise and before the descent. The crewmembers should obtain the ATIS information and set up the navigation radios for the approach before conducting the briefing. If the ATIS is not available, the weather forecast from the dispatch release or preflight briefing can be used.

Briefing a Jeppesen approach plate is simple thanks to its logical format. Start at the top with the airport, date of the plate, approach number and title to confirm that both crewmembers are looking at the same approach plate and that both plates are current.

Most briefings skip the top line, which contains communications frequencies. Air traffic control gives the pilot the next frequency when they are handed off, but the frequencies on the approach plate are useful in order to preset tower and ground frequencies in the radio’s standby field. The ATIS frequency can also be found there.

The next line of the plate contains navigation information. In the case of ILS 35R, the plate contains the localizer frequency (111.3) and identifier (IAPA). The final approach course is 350 degrees. Verify that the nav radios are set to the proper frequency and HSI needles are set to the inbound course as you brief. The decision altitude (DA) for the approach is 6,085 feet above mean sea level (MSL), which is 200 feet above the ground (AGL). If your airplane has a place to set the DA, verify that it has been done correctly. If the DA, cannot be set exactly, round up. For example, if you can only set the DA in 100 foot increments, set 6,100. The elevation of the touchdown zone of the runway is 5,885 feet.

The circle on the right side of the page gives the minimum safe altitude. This provides 1,000 feet of clearance within 25 nautical miles of the fix referenced. In this case, the fix is CASSE, the locator out marker with the identifier AP. The safe altitude is 8,100 MSL in the direction of flight, but rises to 13,100 in other directions. The boundaries for the altitudes are noted as 140 degrees to (320 degrees from) and 250 degrees to (130 degrees from) CASSE.

To follow a logical order, skip the missed approach procedure for now and look at the notes. Several notes apply to this approach. ADF or DME is required to identify CASSE and radar is required. The glideslope and VGSI (visual glide slope indicator), in this case a PAPI (precision approach path indicator) on the right side of the runway, are different so the airplane may not appear to be on the visual glideslope if it is tracking the ILS.

The transition altitude and transition level in the notes section are used when flying outside the United States. This tells pilots where to change between standard and local altimeter settings. In the U.S., this is done at 18,000 feet (Flight Level 180), but in different countries these altitudes may change.

The plan view in the center is the “God’s eye” view of the approach which looks down like a typical map. In most cases, aircraft will be given radar vectors to join the final approach course, but if you expect to fly a transition you should brief it. The ILS 35R does not have transitions, but there is a speed restriction, 210 knots at FIRPI intersection. The note labeled “1” at FIRPI points out that radar or DME is required to identify the fix. At this point, verify that the frequency for CASSI (260) is set in the ADF.

The plan view also notes obstructions and terrain with their MSL heights. The brown areas in the bottom left corner denote high terrain. The highest point on the chart is marked with a black arrow. In this case it is 8,068 feet MSL to the southwest. Obstructions and terrain may be briefed if they are applicable. For example, in particular pilots arriving from the west would want to consider the high terrain that will be encountered as they are vectored for the approach.

Below the plan view is the profile view, a side view that shows altitudes to be flown. In most cases, controllers will instruct the aircraft to descend as they vector it towards final. The aircraft should be at 8,000 feet as it approaches CASSI. However, if the airplane is instructed to fly to FIRPI, the mandatory crossing altitude is 9,000 feet for that fix. If the approach is an ILS, other altitudes in the profile view can be disregarded. They apply only if the ILS glideslope is out of service and the airplane is flying a localizer only approach.

Also in the case of nonprecision localizer approach, the maltese cross over CASSI and any stepdowns should be briefed. The maltese cross represents the final approach fix. For an ILS, the final approach fix is at glideslope intercept at the published altitude (8,000 feet).

The missed approach point (MAP) should also be briefed. This can be determined several ways. For an ILS, the MAP is the DA on the glideslope. For a nonprecision approach, the MAP can be determined by the “M” on the profile view at 1.8 DME or by the box below the profile view. For a groundspeed of 100 knots, the MAP would be reached three minutes and 47 seconds after crossing CASSE.

Next to the missed approach box is a graphic description of the runway lights, in this case MALSRs and a PAPI, and simplified depiction of the missed approach procedure. Brief the missed approach with either the simplified description here or the textual description above the plan view.

The bottom of the approach plate contains information on the approach’s minimums for a variety of conditions. Ensure that the DA (or MDA if nonprecision) briefed above is correct for aircraft approach category and available equipment. The maximum speed for each approach category is printed with the circling information for reference. Check for notes that affect minimums such as note 1 which states that sidestep or circling to 35L is not authorized at night if the 35L VGSI is not operative.

The full instrument approach briefing might sound something like this:

This is the ILS 35R approach to Centennial airport, February 1, 2013, 41-1.

The localizer is 111.3 and inbound course is 350, set right and left. Glideslope at CASSE is 7,977 and DA is 6,085, which is 200 AGL. Minimum safe altitude is 8,100 to the northeast and 13,100 in all other directions. ADF or DME and radar are required. The glide slope and PAPI are not the same. Frequency for CASSE is 260. There is mountainous terrain to 8,000 feet to the southwest. There is a mandatory 9,000 foot crossing altitude and 210 knots at FIRPI which is 14.5 DME based on the localizer. Inside FIRPI we can descend to 8,000 until intercepting the glideslope. There is a PAPI to the left.

The missed approach point will be the decision altitude of 6,085 feet. The missed approach procedure is to climb straight out to 7,400 then make a right turn while climbing to 9,000 and intercepting the localizer southbound. Holding will be over CASSE at 9,000 with a parallel entry. Minimums for the approach are a half a mile visibility.

Originally published on

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