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Travelling with Czech Airlines via Prague in an ATR-72 I have already experienced multiple times that instead of pushback service the planes simply used their reverse thrust to leave their parking position, even doing a 90° degree turn while rolling backwards.

Personal experience as well as a Google search show that this is rather uncommon. What makes the ATR-72 special to be able to perform such kind of manoeuvre?

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  • $\begingroup$ Related $\endgroup$ – Pondlife Aug 2 at 0:52
  • $\begingroup$ Was it really powering back from a gate (with a jetbridge and co.)? I've never seen an ATR-72 parked at a gate in PRG, I think they exclusively park on the apron (and board via buses), which means they have lots of room around them for powering back and also that no pushback tractors are typically around. $\endgroup$ – TooTea Aug 2 at 9:51
  • $\begingroup$ @TooTea Yes, as you correctly assume this was on the apron and not at a gate. However, I still find it quite unusual. $\endgroup$ – elzell Aug 2 at 11:11
  • $\begingroup$ @TooTea Ah, now I see why you are asking - someone edited the title of my question. Fixed that. $\endgroup$ – elzell Aug 2 at 11:13
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As other answers note, for most aircraft, the risk of the engines ingesting FOD while powering back is too high. This is particularly true for turbofan engines mounted under the wings.

Turboprop engines tend to be mounted on high wings (such as on the ATR-72), and they tend to serve smaller airports where an airline may not have tugs available for pushback. Regional and private jets, which often have fuselage-mounted engines, also tend to serve such smaller airports. These planes were designed with the engines mounted higher specifically to reduce the risk of ingesting FOD, thus allowing them to safely power back when needed.

Note that powering back still burns a lot of fuel, and even with high engines the FOD risk isn't zero, so when operating at larger airports that do have tugs available, airlines will generally use them.

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Just about any turboprop or piston engine airplane with reversing propellers can do it, as the airplane doesn't care whether BETA reverse is being used on the ramp or a taxiway or a runway. You normally use DISCING (flat prop blades to make zero thrust) when taxiing when you want slow down or when you are stopped. To go backwards, you just move the powers back out of DISCING a touch.

You kick up FOD on the ramp, which a TP can draw in almost as easily as a jet. Gate areas are a garden of zipper tags from luggage and will do major damage to a TP if they get past the particle separator in the nacelle, which is more likely on the ground without a high velocity air stream to let the separator do its job. The airline has probably made the business decision to take the risk of FOD damage to avoid having to use tugs for pushback.

When you want to stop backing up, you should not use brakes, lest you tip back. You use forward power.

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Pushback via reverse thrust is problematic for turbofans, as they kick up lots of debris, which could be ingested into the engine or hit something laying around.

Presumably the ATR as a turboprop doesn't create as much wind, and with a turboprop the reverse thrust is blowing from the front of the engine, so there's no chance the debris will reach the intake.

Turbo prop reverse thrust

Most modern commercial airliners are prohibited to power back. Ground operations in aircraft fitted with high-bypass engines are usually restricted to idle and low-idle operations (enough to make the craft start moving, after which momentum enables further movement with idle only). Aircraft capable of power back are predominantly thus turboprops, several operators of these allow their crews to operate accordingly.

Is a powerback allowed by airlines as a safe maneuver?

Related: Is it possible to use thrust reversers to taxi backwards?

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    $\begingroup$ Turboprops have two key advantages over turbofans when in reverse: not only is the intake smaller and higher off the ground, but the thrust point is forward of the intake and thus less likely to lift FOD towards it. $\endgroup$ – Chromatix Aug 2 at 6:23
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    $\begingroup$ I wouldn't say that there is NO chance of FOD.. Engine intake is below the engine on the ATR-72, the prop is pulling air forwards as shown on your diagram, engine is pulling in air at the same location. Any FOD that the reverse thrust picks up could just as easily enter the engine. $\endgroup$ – LStrom Aug 2 at 12:09
  • $\begingroup$ One big popular exception was the MD-80 which used to routinely powerback with its elevated tail mounted turbofans being high enough from the ground to reduce the risk of FOD ingestion. $\endgroup$ – J... Aug 2 at 12:45
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You can do powerbacks with basically any commercial turboprop, not really uncommon at all. We did it regularly with our F50s and we still performing it nowadays sometimes (even though quite rarely) with our DH8Ds when there is no towbar available.

Never heard about the problem of ingesting FOD, we never experienced this. The only thing you have to be careful about is NOT to use the normal brakes for stopping or you will end up with a tailstrike. Instead one has to go back to DISC.

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