So I understand that ATC controls your heading and altitude. They don’t (to my knowledge, and gleaned from playing flight simulator only) regulate your speed and ascent/descent rates.
So,
a) is that true?
b) are there “set” or standardized climb/descend rates that are used so that everyone’s on the same page?
c) are there set or standardized speeds, particularly for landing patterns/following aircraft on approach/etc.
thanks!
Yes there are many speed restrictions. Many of them are blanket restrictions that apply to everyone at certain phases of flight and sometimes ATC will give specific speed instructions.
Examples off the top of my head:
Max speed 250 knots indicated (KIAS) when below 10,000’
Max speed 200 KIAS within 4 nm of a Class D control zone
Approach speeds for Cat B aircraft (think light twins up to medium sized turbo props, smaller and larger aircraft have a different set of speeds.):
Speed past the initial approach fix 120 - 180 KIAS
Speed past the final approach fix 85 - 130 KIAS
Max speed for circling 135 KIAS
Max speed for a missed approach 150 KIAS
There are also holding speeds that vary with altitude and a common form of procedural separation for aircraft in trail is to limit one to a minimum Mach No. and limit the other to a maximum Mach No. ATC will also give time requirements which have the same effect as a speed restriction. E.g. they’ll require you to be at a certain waypoint at a certain time and you achieve this by moderating your airspeed. Another way ATC use speed is to ask for your “best speed” on approach, they’ll do this when you have following faster traffic.
If you have access to it, the specific speed regulations for your country are contained in your country’s Aeronautical Information Publication or the Jepessen Airway Manual.
There are standard rates of descent. The minimum rate of descent is 500 fpm. There is no maximum that I’m aware of but ATC can tell you to use the standard rate, I can’t remember what that is though. Will look it up today, but I someone else will beat me to it I’m sure. You can’t really enforce climb rate restrictions because aircraft are normally climbed at a particular airspeed rather than a vertical speed. If there is a need for vertical separation, ATC will give altitude restrictions rather than climb rate restrictions.
Just to add to the already excellent response, regarding climb/descent rate, in the US, the expectation is a minimum of 500 fpm and no maximum except during the last 1000 ft before reaching the new assigned altitude. Within the last 1000 ft, the pilot is supposed to maintain 500 - 1500 fpm. The reason for the restriction is to avoid triggering a false alarm in case there’s another aircraft with collision avoidance system nearby, since its computer can’t possibly know if the rapidly approaching aircraft is really going to level off or not.
Yes, speed control is routinely used around busy airports during the arrival phase. That’s one of the primary tools available to controllers to keep everyone separated at the required minimum distance and keep traffic moving.
Airplanes have a wide range of speeds, much more so than the different ground vehicles. It is possible to have aircraft of wildly different capabilities all in the same traffic pattern.
As an example, I once flew into Fort Wayne, Indiana (Class C airspace for the curious) and ATC put me behind an F-14 and in front of a Boeing 737. Those are two pretty fast airplanes. I was in a Cessna 150 with a top level speed of just under 100 mph. Those other two airplanes would stall and stop flying at that low an airspeed. And yet, we were all on the same “road” so to speak.
This is why ATC is there - to coordinate such traffic problems. They are trained to cope with the problem of aircraft at different speeds converging or taking off from the same spot. In that case, we all landed after one another with no incident and no problem, all we had to do was follow ATC directives.
So while there are, in a sense, standard speeds for a particular model of aircraft, or recommended speeds for those activities, there is no ONE standard speed. ATC is familiar with a lot of aircraft and usually know about how fast everyone is (or isn’t) and will plan accordingly.
If they don’t know - I hang out with people who fly antiques as well as experimental and homebuilt airplanes - they will ask you. In which case you say “recommended approach is XXX for this aircraft.” Or you might say “same speeds and limitations as a Cessna 172” or whatever well known aircraft model is applicable. They might ask if you can go slower or faster, depending on the circumstances, and you let them know if it’s possible to comply safely.
I’m sure at at times ATC can get annoyed with traffic of vastly different capabilities but they’re usually too professional to let it show. Actually, most of those I’ve talked to would probably enjoy working out the problem. If they didn’t like that sort of thing they wouldn’t last too long as controllers anyhow.
Completely off topic, but talking about different airplanes with their different capabilities begs the Aspen 20 groundspeed check story excerpted from Brian Shul’s book about being an SR-71 pilot.
Not much in the way of specifics to add to the excellent posts already. But to put some perspective on the overall picture, at least in the US …
In non-hub non-major cities the traffic is sparse enough that each airplane is mostly able to fly the speeds & climb & descent rates which best suit it. I can launch in my airliner just a couple minutes behind **Broomstick **in her Cessna. By the time I get airborne she’s turned out of my way & we each go our separate paths. Withing a minute I’ll be above & ahead of her & she’ll never catch me after that. So no traffic conflict.
If departing ahead or behind another jet, odds are our courses will diverge soon enough since we’re probably not going to the same place. We do sometimes get in a situation where we’re going the same way for at least the first 10-15 minutes and we have incompatible speeds, with the inherently faster airplane behind. The fast one will be slowed back by ATC, which in turn leads to a steeper climb. Meanwhile, the one in front will be asked to go as fast as practical. Which leads to a flatter climb for him/her. After a few minutes enough altitude separation exists that both can resume normal speeds with the fast airplane above the slower one ahead. The courses eventually diverge & the problem is solved.
At busy hub or big city airports it’s typical that ATC develops different prescribed departure paths for 3 classes of aircraft: light planes, turboprops, and jets. The jets tend to be the only group which has both enough traffic density and enough speed disparity that it becomes an issue for ATC to manage speeds. If so, the departure path procedures will dictate specific speeds at various points which are generally compatible with typical bizjet / airliner speeds. If everybody sticks to the procedure speeds separation will largely take care of itself.
If the OP is looking for ballpark climb speeds to be realistic when simming, something in the 280 to 320 KIAS range would be good for any jet. In the mid-high 20s altitude range, switch from flying IAS to flying Mach. You’d normally do the high part of the climb at whatever your cruise Mach will be. That can be anywhere from M0.74 to M0.90 depending on the aircraft type. Absent any other info, M0.79 will work well enough in any jet. As a general rule, the faster the cruise Mach, the faster the IAS climb speed should be also. E.g. flying a Citation I biz jet which cruises at M0.73 will probably climb at 280 until reaching M0.73 them maintain that Mach up to cruise altitude. A 747-400 which cruises at M0.85 will probably climb at 320 until reaching that M0.85 then maintain that to cruise altitude.
Descent, arrival, approach, and landing are conceptually similar. In high density environments the published procedures are very prescriptive & everybody ends up traversing close to the same path through space and at the same speeds. At low density airports there’s a lot more freedom to fly the best descent profile & speeds for your particular airplane.
The typical decent is flown just like the climb but in reverse. Pull the power to idle, maintain cruise Mach until intercepting the IAS you used for climb-out, then maintain that IAS until it’s time to slow for 10,000’ (see below) and then for landing. You pick the *place *to start descending so that idle power plus those speeds puts you in the right spot in the sky to make the landing with as little added power as possible. At least that’s the ideal. In any environment with traffic, ATC will descend you early and you’ll end up descending and or driving around at lower altitudes at partial power to reach the field.
Speaking strictly to the last few miles before landing …
ATC’s goal is to have airplanes touching down every *X *seconds, as close together as will get one pulling off the runway shortly before the other one lands. *X is typically about 60 seconds. So upstream the enroute ATC’s job is to get the jets spaced out at about 2X *second intervals when we’re going a lot faster & as everybody slows, the space between airplanes compresses along with the time.
At moderately busy airports it’s common to have ATC control your speed up to the final approach fix (FAF) generally about 5 miles short of the runway. As **Richard Pearse **said above, there’s a speed limit of 250 KIAS below 10,000 ft, so everybody is already doing that speed once down below 10,000’. During pattern manuevering it’s typical to slow to 210 or 200. Another common retriction from base and onto final is to maintain 170 or 180 KIAS until the FAF.
Beyond that point it’s necessary to aggressively slow and quickly finish lowering gear & flaps to get down to landing speed before you get too close to the runway. So ATC is hands-off in that segment. If they allowed enough space ahead of you it will all work out. If not, the end result is a go-around for the trailing airplane when he/she gets to the threshold & the preceding airplane is not yet off the runway.
Half the fun of airline flying is trying to manage your descent to use the minimum possible power (& hence fuel) all the way from cruise a hundred miles from the airport, through all the ATC speed / altitude wickets on the way down and all the way to short final: on speed, in position and properly configured. The ever changing winds all the way down always add some wildcards to the game.
Everything I wrote above is applicable to bizjets or jet airliners. if you’re simming with fighters they represent a whole 'nother set of performance characteristics.
Normally both the military & ATC want to keep fighter traffic well away from other aicraft; the two groups just don’t mesh well.
On climbout, fighters will typicaly do 350 KIAS to cruise Mach, which is typically in the low 7s, e.g. M0.72. Thats for a non-afterburning climb & they’ll still be climbing far more steeply than airliners. In burner it’s more a matter of just going almost straight up to altitude then leveling off. That’s not real efficient because you A) burn a lot of gas and B) don’t get very far down-range while doing it.
Fighter cruise altitude tends to be in the high 20s or low 30s. That’s where the smallish wings are still big enough for the amount of atmosphere available.
In descent fighters main concern is their fairly low fuel supply. The long gradual descent used by airliners & bizjets could leave the fighter very low on gas if the weather goes bad any time during that descent. So the predominant technique is to arrive over the landing base at near cruise altitude, make a weather decision to land or divert, then dive down to low altitude (~5,000 ft) then intercept a more normal instrument or visual approach & landing.
The so-called “penetration” from high altitude is flown at 300 or 350 with idle & speedbrakes to minimize the time & distance in the descent. A typical path is outbound from directly above the base for 15-ish miles, then a 180-plus-a-bit degree turn to intercept final to the runway still diving & going fast. Once on the normal 3 degree slope to the runway, stop the dive, leave idle & speedbrakes out and add gear & flaps as the speed drops off to normal landing speed. Add power on short final and land. Viola!
Final approach speeds for modern USAF fighters are compatible with airliners, e.g. 130-150 KIAS depending on weight. Modern Navy fighters are normally a bit slower (110-140) since they’re designed for landing on real small runways. The older 1960s-era fighters (Century series, F4s, etc.) flew final a bunch faster than airliners, say 160-190 KIAS.
My story is nearly the complete opposite of yours.
I used to fly a Britten Norman Islander which is a slow, fixed undercarriage, high wing, piston twin. It’s a very easy aeroplane to fly and there’s only one important speed to remember; two engine climb is 65 knots, single engine climb is 65 knots, and approach speed is 65 knots. It cruises at around 120 knots on a good day. It normally carries around 10 passengers I think, though ours were fitted out for visual coastal surveillance with four crew seats, a life raft, a comprehensive radio stack including aviation, military, and marine frequencies, satphone, HF and so on. Up the front we had a weather radar, GPS, and a fuel computer in addition to the standard instrument kit. The fuel computer was linked to the GPS and the information it fed to the GPS allowed it to work out lots of interesting things, one being our Mach no.
Where we operate there is no ATC radar so the ATC control is all procedural and relies on nominated cruising speeds in the flight plan and the pilots giving progressive estimates for their next reporting points throughout the flight. The ATC system will also show an estimate for the next reporting point based on the nominated true airspeed and forecast winds. Sometimes the pilot’s estimate will differ significantly from the ATC system estimate and ATC will request your groundspeed (with no radar ATC don’t have this information themselves.) I understand they use this to validate and perhaps update the forecast winds. When this happens with the airline jets ATC will also ask for their cruising Mach no. which is normally somewhere around 85% of the speed of sound, or Mach 0.85.
This one time, we’d just gone off task and were climbing the Islander to 8000’ for the transit home and the upper winds must have been a bit different from forecast as various airlines were being asked for ground speed and cruising Mach no. E.g.,
Centre: “Speedbird 5 report groundspeed and cruising Mach no.”
SB5: “Speedbird 5 groundspeed 500 knots, Mach 0.83”
We got to top of climb and I reported to ATC.
CW123: “Brisbane Centre, Coastwatch 123, maintaining 8000, Broome at 15.”
Centre: “Coastwatch 123, Brisbane Centre, report groundspeed.”
I couldn’t resist.
CW123: “Coastwatch 123 groundspeed 130 knots… and ah, would you like our cruising Mach no.?”
Centre with a smile in their voice: “Roger go ahead!”
CW123: “Coastwatch 123 cruising Mach no. 0.17!”
Centre: “Coastwatch 123, thanks!”
Wow, thanks LSLGuy!
Sweet!!