The Chart Clinic– Database Series

1 And if you look closer at the RNAV approaches, there are two of them to thesame runway -- Rwy 15R. After lookingat the titles a little closer, the RNAV Rwy15R approaches actually have a small difference. The first one has the letter Y after the word RNAV and the second approach has the letter Z afterthe word RNAV. Multiple RNAVA pproaches to theSame RunwayBecause databases cannot handle duplicate file names, two approach procedures with the identical name tothe same runway cannot be included inthe Database . Recently, the FAA issuedtwo different RNAV approach proceduresto Rwy 15R at Baltimore, Maryland. TheFAA coordinated with industry to handlethe duplicate name situation and theyadopted the use of a phonetic letter as asuffix to the procedure type to handlethe duplication to the two approaches at first RNAV approach is named RNAVY Rwy 15R and the second RNAV approach is named RNAV Z Rwy policy is to use a letter starting at theend of the alphabet and proceed backward so as not to be confusing with approachesthat don t have straight-in landing minimums.

2 Yourecall that circle-to-land onlyapproaches use the alphabetletters starting at the beginning of the alphabet. That letter appears after the approachprocedure type. Then, the runwaynumber is eliminated to indicate nostraight-in landing minimums. So, a circling approach would be identified as VOR - the controller issues a clearance for the approach toBaltimore, the clearance would be .. cleared for the RNAV YankeeRwy 15R approach. The phoneticletter is pronounced by the controller in the Two Virtually IdenticalApproaches?The FAA is trying hard to accommodate both the panelmounted GPS receivers as well as theFlight Management Systems thathave VNAV capability.

3 On the RNAVZ approach, there is a stepdown fix(after KEVVN waypoint) to providebetter minimums for the GPSreceivers that don t have VNAV. Thestepdown fix which is NM to therunway allows the avionics withoutVNAV to pass the final approach segment controlling obstacle andcontinue on down to an MDA of 560 there is VNAV on RNAV Y Rwy 15R, thereis no need for a stepdown fix -- the VNAV willkeep you above the final approach segmentobstacle. Without VNAV, the stepdown fix isnecessary to clear the aircraft with FMSs, the RNAV Y approach wascreated by the FAA to utilize the VNAV to passthe controlling obstacle on a descending the VNAV provides descent guidance all the way from the FAF to the RW15R missedapproach point, the VNAV guidance clears theobstacle without having to identify the stepdown fix which is included in the other the RNAV Y approach, the LNAV minimumsare considerably higher (800 feet) than theLNAV minimums on the RNAV Z approach (560feet).

4 This is because there is no stepdown fixon the VNAV approach so the controlling obstacle is higher for no of the two different means of clearingthe obstacle on the final approach segment, youcan see some of the main differences in the minimums box of both approaches. The minimums for RNAV Y Rwy 15R include a decision altitude (DA) because the minimumsare based on lateral navigation (LNAV) and vertical navigation (VNAV) and the minimumsare slightly lower than the RNAV Z Rwy 15 Rapproach. The RNAV Z Rwy 15R approach hasminimums which are expressed as a minimumdescent altitude (MDA) because there is no vertical Chart Clinic Database SeriesPower is set for cruise, engines are synched,trim is all set, comm radios properly tuned,GPS receiver set to a waypoint close to thedestination.

5 Time to engage the autopilot andtime to start studying the approach charts again-- before having to use all the numbers and lineson the Chart while shooting the is your destination. As you get closer,you tune into the ATIS, weather is 600 broken, 2 miles vis, wind 130 at 12 knots, landing runways 15 left and right. So now you knowyou ll need to shoot an approach. As you lookthrough the approach charts, you find sixapproaches to the two parallel runways -- twoILS approaches, one VOR DME, and three RNAV approaches. OK -- it makes sense to have an ILSfor each of the two parallel runways, but whythree RNAV approaches to two runways?BYJAMESE. TERPSTRASR. CORPORATEVICEPRESIDENT, JEPPESENJ ames E. Terpstra is seniorcorporate vice president, aviation affairs at Jeppesen.

6 Hisratings include ATP, single andmulti-engine, airplane andinstrument flight instructor. His6,000+ hours include 3,200instructing. For comments, please industry should be able to support multipleapproaches of the same type to the same runway sometime in the Spring 2001 so the Chart will be revised to take the ProcedureNot in Database note off the Chart when duplicate approaches can be utilized in airborne the next article, we will begin exploring whysome information is different on the charts thenon the avionics Descent PointThe visual descent points are in different locations because they are based on reachingthe MDA on the descent angle of from theFAF down to 62 feet above the threshold. Sincethe MDA of 800 feet on RNAV Y Rwy 15R isreached before the MDA of 560 feet on RNAV ZRwy 15R, the VDP is further from the runway onRNAV Y Rwy 15R.

7 The FAA has a policy ofadding more and more VDPs on RNAV approaches and other approaches where there isa DME that can be used on the of the main differences can be found bylooking at the missed approach procedures onboth charts. The missed approach on RNAV YRwy 15R climbs straight ahead to 2,500 feetdirect to RANGL waypoint, then a right turndirect to SAYLR, and then a right turn direct toDATED waypoint which is the missed approachholding fix. The missed approach point andmissed approach holding fix both have a symbolwith a circle around them. This means they arefly-over fixes. The RANGL and SAYLR waypointsare fly-by fixes and are depicted as waypointsymbols without circles around them. On themissed approach depiction (with dashed lines),the actual track does not pass through RANGLand SAYLR since turn anticipation at each fix willcause them to be passed on the missedapproach, but you will not fly over missed approach points and missedapproach holding fixes are fly-over waypoints bydefinition.

8 Virtually all other fixes are fly-by advantage of a fly-by waypoint is that agood rate of turn will cause you to be on thecenterline of the next leg after passing the way-point rather than trying to re-intercept thecourse after over shooting the fix when Not in DatabaseIn the plan view of the Baltimore RNAV Z Rwy15R approach, there is a note Procedure Not inDatabase. As stated earlier, the FAA and industry coordinated the use of the phoneticalphabet starting with the letter Z and movingbackward in the alphabet to indicate duplicationof approach procedures. The coordination ofthe phonetic letter was accomplished but thecoordination of the implementation date was meant that the avionics systems and thedatabases were not ready to implement theduplicate function when the FAA began issuingthe new duplicate approaches.

9 A decision wasthen made to include one approach procedurein the Database and not both. The approachprocedure with the best minimums and VNAV capability was selected so the RNAV Y Rwy 15 Rapproach was selected. This left RNAV Z Rwy15R as an approach procedure on paper withouta Database . Since the FAA requires that the GPSapproaches must be in the Database , it wasdecided to publish the RNAV Z Rwy 15R in theapproach manuals, but include the note Procedure Not in Database to indicate that aclearance for that approach could not be accepted since there were no Database recordsto support Current Data in Minutes with SkyboundFax your order to 303-328-4153To order:Call 1-800-621-5377 Navigation Data At E-Speed. Anywhere In The Skybound, Jeppesen NavData customers have the convenience of downloading theirdata from the Internet at e-speed.

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