I planned a route from KIAD to EGLL using a United route from FlightAware.  The last few waypoints are SLANY, STU, and NUMPO which gives a straight in approach to Rwy 09R at EGLL.  Attached is what my course looks like using "PLAN" and "STEP."  Never saw anything like this before.  Why does the flightplan show a circular path?  The waypoints look fine on the computer.

 

drdickie - I would like to help you out but I don't see any attachment on your post.

 

Try to add it on again and I'll get back to you.

Very odd.  The attachment was clearly attached and I got no error message on submitting.  Trying again.

Almost like a holding point with zero time at NUMBO. I'd be checking the FMC Legs page to see what happens at NUMPO other than an ordinary crossing.

What program are you using to plan your flight?  Is it possible that you are looking at a "great circle" route?  Unless planning a route along

the equator,  and if the route is over a significant distance, the  raw route (before waypoints) are added, will have a semicircular appearance.

Some of my routes look semicircular after the waypoints are added because (unless flying along the equator) a semicircle in most flight

planning software will describe a shorter route (frequently much shorter)  than a straight line.  Hope I didn't botch up this explanation too 

badly ~

Best regards,

Ken

Also,  if you are speaking of small circles between relaively close waypoints, this happens if the flight management computer determines that

the waypoints a too close together at "plan speed" to execute a smooth climb or descent between them.  Can also happen if the waypoints

are out of sequence in the flight pan.  I've seen not only circles,  but french curves, and all sorts of hard to describe flight paths

Hope this helps,

Ken

I've seen it before when altitude vs speed constraints make a straight in approach unable. This is awful close to TOD, how far from the airport is the CDU starting descent? I take it that this isn't part of a STAR? Interesting.

I am not using any planning software.  Just entering the UAL924 flight plan as reported on FlightAware into the 777 computer.  I will double check on the other suggestions regarding TOD, etc.

 

Thanks to all.

What program are you using to plan your flight? Is it possible that you are looking at a "great circle" route? Unless planning a route along

the equator, and if the route is over a significant distance, the raw route (before waypoints) are added, will have a semicircular appearance.

Some of my routes look semicircular after the waypoints are added because (unless flying along the equator) a semicircle in most flight

planning software will describe a shorter route (frequently much shorter) than a straight line. Hope I didn't botch up this explanation too

badly ~

Best regards,

Ken

 

Also, if you are speaking of small circles between relaively close waypoints, this happens if the flight management computer determines that

the waypoints a too close together at "plan speed" to execute a smooth climb or descent between them. Can also happen if the waypoints

are out of sequence in the flight pan. I've seen not only circles, but french curves, and all sorts of hard to describe flight paths

Hope this helps,

Ken

On a 80 mile radius plan view even great circle route legs will appear straight. I've never heard of an FMC adding loops to a plan to cope with speed and altitude restrictions. It usually gives a warning message such as descent path not available.

 

Such a loop can appear in a SID or STAR if the route definition says turn right when the natural turn would be to the left, or vice versa. Not sure why it would occur en route but that is what it looks like.