Performance Based Navigation (PBN)

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‘Climb Via,’ ‘Descend Via’ Simply Mean Fly the Published Procedure

April 21, 2014

Listen to an NBAA Flight Plan podcast for more on climb via and descend via.

In an airspace increasingly composed of RNAV fixes and the routes they define, the FAA has introduced new phraseology for the delivery of IFR clearances: “climb via” and “descend via.” Whether used in conjunction with standard instrument departures (SIDs) or area navigation standard instrument departures (RNAV SIDs), climb via is simply shorthand for “fly the departure as published.”

“Some pilots are confused by this phraseology,” said Keith Gordon, director of aviation at Flynn Gallagher Associates in Las Vegas, and a member of NBAA‘s Access Committee. Gordon has been heavily involved in the creation of RNAV SIDS/STARS in the Las Vegas Valley – among the first such procedures in the nation. “But once you understand the basic concept that this is simply verbal shorthand for ‘fly the published procedure,’ it becomes much easier to grasp.

“The new phraseology has been 10 years in development by first, the FAA’s Human Factors team, then the Pilot-Controller Phraseology and Procedures Action Team, under the PARC (the Performance Based Operations Aviation Rulemaking Committee),” Gordon said.

With more air traffic comes more radio congestion. The new phraseology is briefer than previous methods of communicating instructions, and cuts down on the number of words that must be spoken in conjunction with an initial or revised departure clearance.

“Climb via and descend via clearances can be coupled with exceptions to the published procedures. Let’s say on climb out you need to be held down to avoid other traffic, so you might hear ‘Falcon 1234 climb via the PRYME departure except maintain 5,000.’ That lets you know that you’ll stop climbing short of the published top altitude,” Gordon explained. “Otherwise, you fly the procedure as published.”

There are always three components to a SID or STAR (standard instrument arrival procedure): lateral (procedure track), vertical (level, climb or descent) and speed.

“Any one of those can be amended with an exception, while the rest of the clearance remains intact,” Gordon said. All aspects of the SID/STAR are mandatory unless amended by air traffic control (ATC).

“What you’re doing when you use the climb via or descend via clearance is establishing clarity between the pilot and the controller,” Gordon added. “The pilot is agreeing to fly the published procedure track and obey all speed and altitude crossing restrictions; hence the controller knows what to expect the aircraft to do.”

That agreement is affirmed through the flight crew’s verbatim read back of the clearance, according to the NBAA web resource on Climb/Descend Via, which states, “Abbreviated read backs will result in controllers repeating instructions until pilots give verbatim read back of the clearance…Phrases such as ‘on the’ or ‘descending on’ a procedure are not acceptable phrases and can create additional ATC workload to verify the clearance that was issued to the pilot by the previous controller.”