Seems like Simbrief STAR arrivals flight levels way off from official jeppessen or FAA plates. Why?
2 Likes
Altitude on the chart are limits/restrictions, such as “at or above FL160”, meaning you can cross the point as long as you’re higher than FL160.
Simbrief gives actual climb and descent profile, though their profiles are usually too aggressive
1 Like
Simbrief ignores SID/STAR restrictions and instead goes for the most efficient climb/descent based on various factors.
4 Likes
Obviously a descent rate of more than 3000fpm is not efficient with no obstacle insight.
A continuous, steep, fast descent is more fuel efficient than a stepped, shallower, slower descent. Your engine power will be lower on average. Simbrief aims for the most fuel efficient profile based on various factors.
3 Likes
But for climb it’s a different story. I also want to add simbrief doesn’t respect alt restrictions for approach since simbrief expects you to fly the whole approach instead of taking shortcuts or vectored by atc. This means you have no control over the approach when following their profiles.
1 Like
I get my flight plan from Simbrief and then I’ll use Fltplan Go to look up the STAR at my destination and adjust the altitudes to match the chart. If the chart doesn’t have many altitude restrictions I’ll adjust the descent rate to roughly 1000 ft for every 3 nautical miles.
But with fuel burn rate from simbrief and actual infinite flight rate, we get way more fuel than need it, so fuel efficiency wouldnt matter here. So, is there any easy fix to this for a casual user besides all the expert technical tweaking of airframes which im not willing to put in time unless there is somewhere where already made airframes i can just use exist. Assuming fuel is the main culprit.
This just isn’t true. Staying higher for longer is more efficient, and so is descent with idle thrust. If you watch one of those Real Airline Pilot streams on YouTube using desktop sims (e.g. flightdeck2sim, 320 Sim Pilot, V1 Simulations, easyjetsimpilot, etc) you’ll see they regularly climb/descend more than 3k ft/m. IF pilots tend to be very overly cautious of “aggressive” climbs/descents.
The most ideal descent would be a flight idle continuous descent. A continuous descent just means as little variation descent path as possible. Bare in mind “flight idle” is usually higher than idle on the ground, but IF doesn’t take this into account. I believe it’s around 35%-40% N1.
Obviously STAR/ATC restrictions take priority, but even then you can still do as much as you can to control your energy. For example, if you are being vectored further away from the airport you’d want to reduce your V/S to stay higher and consider flying slower — obviously both assuming you haven’t been asked to maintain a certain forward speed or experdite descent. (Bit of a sidetrack there but point being is it isn’t just a case of setting xyz ft/min and leaving it at that).
Simbrief’s altitudes seem pretty descent to me, at least for descent, although you do have to adjust them to meet STAR restrictions.
I think everyone is misunderstanding the point or intent of the OP’s question. The reason the Simbrief altitudes are different is because they are the estimated altitudes that the descent path in Simbrief uses to calculate descent fuel/time and are based solely on a 3° descent angle to the destination airport at a defined altitude (most of the time 2,500’ AGL). Those altitudes, if you choose to use them for actual descent (VNAV) planning, should be cross-checked against published charts if you’d like to be as realistic as possible because they don’t necessarily honor them.
Take all of the NYC airports for example. None of those altitudes are ever right because Simbrief only takes into account a 3° descent path to the airport without consideration of the complexity of the airspace like the STAR altitudes do
2 Likes
I usually manual adjust descent altitude where I see a conflict. Conflicted altitudes are usually indicated with amber and red.
What is OP? Lol
Efficient was totally used wrong in my response, what i meant is thst not ideal in alot of ways. Fuel should have never entered the conversation.
Original poster