5.8.13

Ask A Pilot - Aug 5th - Thrust Reversal

To continue our series on questions to be answered by yours truly, I have picked up a question to delve on this week.

Is there a reverse option in the airplane? I swear last time we flew I felt the airplane going backwards, or some other reiteration of the question.

I get asked something like this at least once a month.

There are two separate things at stake here.

Almost all commercial airplanes have reverse thrust, which is a function of the engine. It is one of the methods used to slow down the airplane on the runway, usually early in the landing roll when other factors limit the effectivity of the friction brakes. Therefore, pilots land at idle thrust and usually immediately after touchdown they engage the thrust reversal mechanism. You can sometimes hear a loud roar of the engines, which is the engines going in full reverse.

On jet engines, the mechanism is used to direct the airflow around the engine and back in the opposite direction. This is helpful when trying to slow down an airliner from speeds reaching 280 Km/h, to speeds that allow us to maneuver on ground. It's not always necessary, though.


This first video is a test of the reverser opening and closing on one model of engine, and the next is an older technology that used air buckets to dissipate and redirect engine energy.  You can also see the other moving parts of the wing that help slow the aircraft down. Spoilers on top of the wing and flaps and slats on the bottom. The reverser deploys around 1:45.


The Second part of the question is concerning the "pushback", aircrafts that park near terminals almost always need something to push them back and usually turn them to a favourable direction to start their trip.

Here is a sample of one such solution, a "pushback tractor" lifting and pushing back the airplane.


So, as far as I know most pushbacks are conducted using trucks and aircrafts do have reversers but for slowing down and stopping and not for pushback.

P.S. There was a time when engines were sometimes mounted on the rear of the aircraft, and high on the empennage and it was at least allowed to use reversers to pushback, however most modern airliners have wing-mounted engines which would ingest debris from the ground and damage the engine in high thrust-reversal settings.

Stay tuned for more questions answered, get in touch and ask questions through radi@radiradi.com and
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