Approach Transition Fix Altitude Higher than Bottom STAR Altitude

[emerydc8]

I had heard about someone who selected an approach transition that had a crossing altitude higher than the bottom altitude on the STAR. So I decided to give it a try going into LAX last night from SFO. We were on the IRNMN 2 STAR just outside of DOUIT. The STAR has a bottom altitude of 6000.

I didn't execute, but selecting the CRCUS transition wiped out all waypoints on the arrival that have crossing altitudes between where I was (FL310) and the CRCUS IAF (CRCUS 14000B 12000A), leaving a DISCON between the waypoints. On the waypoints that it didn't completely delete, it wiped out the crossing altitudes and speeds.

This is an exaggerated example, but it is good to make a note of the crossing altitude associated with any approach transition you intend to select, or it could cause some trouble. For instance, if the bottom altitude on the STAR is 6000 and an approach transition had a fix with a 7000 crossing altitude.

[Magoo]

Definitely a bug in the box I guess, although I hope I wouldn't get anyway near CRCUS being vectored at GADDO.

[emerydc8]

Agreed. This is definitely an exaggerated example, but we have some captains here who will select an approach transition no matter what. They're usually the same guys who insist on selecting ABM WPTS instead of just going direct so they can do fuel checks every ten minutes.

It is good to know, though, that any time a selected transition altitude is higher than the bottom altitude of a SID it could bite you.

[Magoo]

Good catch anyway. As for arrivals, I was taught to program the box for what is expected which seems to work most of the time.