Captain discovered that FMC's are designed to sometimes auto load a runway with a particular RNAV de...

Attributes
ACN	1314331
Time
Date	201511
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 198 Flight Crew Type 18000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

During preflight briefing; the crew noted that the route in the FMC defaulted to and loaded a runway for a particular RNAV departure. The active runway was different. If uncorrected; this could have resulted in a huge problem on departure. I inquired of the first officer whether he often sees the runway pre-load to a default runway on our 01 routes. He stated that he thought that about 20% of our routes pre-load a runway. I was shocked to learn this. I believe that this is a bad idea; especially on RNAV routings and even more especially at locations where the wrong runway loaded could result in a major course deviation. It would be fine if the departure was just limited for use from that runway. I realize that our procedures and briefings are designed to catch wrong runway loading errors (which they did in this case) but feel we are setting ourselves up for navigation errors by pre-loading runways in the 01 routes. Chief pilot on call was notified of my concerns.

Original NASA ASRS Text

Title: Captain discovered that FMC's are designed to sometimes auto load a runway with a particular RNAV departure.

Narrative: During preflight briefing; the Crew noted that the route in the FMC defaulted to and loaded a Runway for a particular RNAV Departure. The active runway was different. If uncorrected; this could have resulted in a huge problem on departure. I inquired of the FO whether he often sees the runway pre-load to a default runway on our 01 routes. He stated that he thought that about 20% of our routes pre-load a runway. I was shocked to learn this. I believe that this is a bad idea; especially on RNAV routings and even more especially at locations where the wrong runway loaded could result in a major course deviation. It would be fine if the departure was just limited for use from that runway. I realize that our procedures and briefings are designed to catch wrong runway loading errors (which they did in this case) but feel we are setting ourselves up for navigation errors by pre-loading runways in the 01 routes. Chief Pilot on Call was notified of my concerns.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.