lunes, 15 de mayo de 2023

Precision Approach Radar (PAR): How To Fly A Radar-Guided Approach


There are two types of radar approaches available to pilots: Precision Approach Radar (PAR) and Airport Surveillance Radar (ASR). We've already covered how to fly an ASR here. ATC can provide radar approaches at the pilot's request (where available), and may offer them to pilots in distress regardless of weather conditions to expedite traffic.

When you're flying a PAR approach, ATC monitors your aircraft position and issues specific heading and altitude information over the radio throughout the entire approach.

The greatest benefit of PAR approaches is that you can execute a no-gyro procedure. Assuming standard rate turns, ATC will indicate when to begin and end turns.

While ATC is your guide for radar approaches, it's still your responsibility as the PIC to determine that the approach and landing minimums listed are appropriate for weather conditions.

What Is A Precision Radar Approach (PAR)?

PAR approaches provide vertical and lateral guidance in addition to range information. Much like the ILS, this is the most precise radar approach available. The hardest part for pilots is overcoming the challenge of not having navigation indications in the cockpit. You must couple your heading, vertical speed, attitude, and altitude information with ATC's instructions to safely fly this approach. Most PARs are used at military or joint-use airfields, and any opportunity you have to practice one is a great opportunity to develop flight skills.

The final approach course of a PAR approach is normally aligned with the runway centerline, and the glideslope is no less than 2.5 degrees and no more than 3 degrees. Obstacle clearance for the final approach area is based on the particular glideslope angle for that runway.

Where Can You Find Available Approaches + Your Minimums?

Radar approaches are published in a tabular format in the TPP booklet. PAR, ASR, and circling approach information including runway, DA, DH, or MDA, height above airport (HAA), HAT, ceiling, and visibility criteria are outlined and listed by the specific airport. The DH for PAR approaches can be found in a few places:FAA Terminal Procedures Publication (TPP): The standard packet of all instrument approaches for a certain area (look for "Radar Mins" in the table of contents)

Jeppesen EFB: Radar approaches are published as graphical charts under the "approaches" category
ForeFlight EFB: Radar approaches are published under "approaches" and the FAA TPP insert (non-graphical) is provided

PARs have DH/MDA-Vis requirement, Height Above Airport (HAA)/Height Above Touchdown (HAT) number, and ceiling/visibility requirement.

Have A Radio? You're Good To Go.

The best part about PAR approaches is the lack of equipment requirements. All you need is a 2-way radio to communicate with ATC and functioning flight instruments. If you have a gyro failure, there are also options to conduct a no-gyro approach (which we'll save for another article).

Before flying any radar approach, brief lost-comm procedures with ATC to ensure you have a clear understanding of their expectations.

How To Fly A PAR + What To Expect Over The Radio

Radar approaches can be given to any aircraft on request when the approach control and airport have radar approach capabilities. They might be offered by ATC to pilots in distress or to expedite traffic, but you shouldn't expect to get a PAR clearance unless there's a specific ATC operational requirement or an unusual/emergency situation.

These approaches create a large workload for ATC, so if you want to practice one, find a time when the traffic is light and make your request early.

Here are a few things you'll likely hear on the radio when you fly a PAR approach:"This Will Be A Precision Radar Approach To (Airport Name) Runway XX"

"Approaching Glidepath"
"Decision height (number of feet)"
"Begin descent"
"Heading (heading #), on glidepath, on course"
"Slightly/well above/below glidepath"
"Slightly/well left/right/ of course"
"Going above/below glidepath."
"Going right/left of course."
"Above/below glidepath and coming down/up."
"Above/below glidepath and holding."
"Left/right of course and holding/correcting."
"(Number of miles) from touchdown"
"At decision height"
"Over approach lights"
"Over landing threshold"
"Go-Around" or the pilot calls runway in sight

As you fly the approach, maintain a descent rate typical of other precision approaches for your airplane. Use callouts to acknowledge when you're approaching DH. Just like other instrument approaches, you must have the runway environment in sight to leave DH. If you don't spot the runway environment by the MAP, or lose sight of it as you descend, initiate a missed approach.

What Does An Air Traffic Controller See?

PAR uses primary radar to print a 3D image of your location on approach. The frequency of the radar sweep compared to a standard radar is increased, and the range is decreased to 20 degrees to allow for nearly instant radar feedback.

The approach controller sees a 3D representation of the aircraft position which is composed of two pictures: a horizontal view and a vertical view. The controller compares the aircraft position and height to those required and provides feedback to the flight crew at short time intervals.

You'll Land Without Talking To Tower

One really interesting part about PAR approaches is that you're talking to an approach controller all the way to the ground. Because they're utilizing radar to control your approach, you won't be switched over to a tower frequency before landing.

The approach controller will relay your clearance to land from the tower and then you'll switch straight from approach control to ground control after landing.

Have You Flown A Radar Approach?

You can't find radar approaches everywhere, but they're fairly straightforward and a good thing to practice if you ever get the chance. Where have you flown a radar approach? 

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