"When you land...please call this number"

I got the dreaded call this week, "When you land...please call this number."  For those of you who don't fly, I'm not sure how to accurately describe the feeling pilots get when they hear those words.  I rank this phrase right up there with "say your altitude."  Simple words that strike fear into any aviator.  For me there was an immediate uneasiness in my stomach as I perused my memory of the last hour of flight.

"A pilot lives in a world of perfection, or not at all"

-- Richard S. Drury, "My Secret War"

We departed Palm Springs, California an hour earlier and were cruising at 31,000 feet when Los Angeles Center gave us a phone number and instructions to call SOCAL TRACON after we landed.  SOCAL TRACON is an acronym for Southern California Terminal Radar Approach Control, which controls most traffic in and out of southern California airports.  I immediately knew what they wanted to discuss and knew I had not violated any FAR's, but I still felt slightly uneasy...a little like that feeling you get when a policeman is following you on the highway.  You know you're driving under the limit, your tags and inspections are up to date, but it still makes you uncomfortable to have him back there.

Before we left Palm Springs, I contacted "Clearance Delivery" who issued our en-route clearance.  We were instructed to fly the CATHEDRAL ONE DEPARTURE (CATH1.PSP) V370 TNP then as filed.  Take a look at the departure below.  Departing runway 31L, the procedure called for us to climb on an initial heading of 310 degrees until passing  the Palm Springs 268 degree radial, followed by a right turn direct to the Palm Springs VOR.  After passing the Palm Springs VOR, we would fly the PSP 104 degree radial until passing the EMRUD intersection, then make a right turn direct to PSP.  Confused yet?  The procedure also requires pilots to cross PSP the second time at 6,200 feet before proceeding to the northeast on V370.  Terrain around the airport necessitates these turns, providing more distance to climb above surrounding mountains before venturing away from the security of the valley surrounding the airport.

CATHEDRAL ONE DEPARTURE - Palm Springs, California

Palm Springs International, looking west past the passenger terminal.

I jotted down the clearance on our flight plan then loaded the route into the FMS.  The CATHEDRAL ONE is not an RNAV departure, but I intended to use the FMS to guide us along the route.  An important part of the pre-flight process is the route check.  After I loaded the route into the FMS, the Captain checked my entries as I read from the clearance and the flight plan.  It is standard procedure at most airlines for one pilot to load the FMS and for the other pilot to check his work.

Here's an unrelated video that shows how to load the FMS (also known as the GFMS on this jet).

It was at this point that I noticed a discrepancy between what was depicted on the chart verses what appeared in our FMS.  I took the picture below while sitting at the gate before push back and engine start.  See if you can see the difference.  Take a look at the departure procedure and decide which way you would turn after EMRUD.  Now take a look at what the FMS instructed us to do.  After EMRUD, the chart shows a right turn and the FMS shows a turn to the left.  

The terrain I was most concerned about was west of the airport, so I was surprised that the procedure called for a turn toward the mountains.  But regardless of what seemed right or logical, I wanted to know what ATC was expecting us to do.  Here's where things got a little more confusing.  I asked PSP Clearance to find out which way they expected us to turn after EMRUD.  His response?  "I would expect you to turn left.  There are mountains to the right."  Well, now I was really confused.

After some time and a promise that he would check into the matter, clearance confirmed that the chart was correct.  A right turn didn't seem logical, but that's what the procedure instructed us to do.  The whole thing was a moot point, since we were able to climb fast enough that the teardrop turn after PSP was not necessary.  Even with a fully loaded jet, we were able to climb well above the 6,200 foot restriction and were almost immediately cleared on course.  The picture below is our actual flight path.

An hour into the flight, someone a little higher up in the chain of command at SOCAL got involved and wanted more information.  Thankfully, the ass chewing that usually goes with "call us when you land" wasn't going to happen today.  The moral of the story is to check your FMS or GPS or whatever it is you are using.  Don't assume the data in your device is correct.  Don't assume the guy on the other end of the radio knows the procedure.  Safety is everything...trust but verify.