What are the main differences in flying a Boeing vs an Airbus aircraft?
Ignoring cosmetics, e.g. nose/window shape (see How can I tell apart an Airbus from a Boeing?)
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asked Dec 19, 2013 at 1:55
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30$\begingroup$ On a Boeing, the pilot outranks the auto pilot. $\endgroup$– Edward FalkDec 19, 2013 at 2:33
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14$\begingroup$ On a Boeing, pilots overrule the flight-envelope-protections by attempting to break the controls ("excessive force"). On an Airbus, pilots overrule the flight-envelope-protections by pressing two switches (2xFAC). $\endgroup$– RedGrittyBrickJan 7, 2015 at 15:33
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2$\begingroup$ Airbus' speak French, mon dieu! It's incredibly annoying. $\endgroup$– Tyler DurdenJul 5, 2016 at 21:02
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7$\begingroup$ @EdwardFalk As in an Airbus. The whole Boeing vs Airbus nonsense, to me, sounds like "I don't trust a wing that's not covered in fabric such that I can repair a hole with some cloth snipped from my breeches". FBW and increased automation is inevitable. It is part of the contribution to ever more safe flying with most years making a new record for lower fatalities in absolute terms. $\endgroup$– SimonFeb 2, 2017 at 20:51
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2$\begingroup$ A colleague of mine at another company who switched from Airbus to Boeing and vice versa a few times gives his account here (and at a few other places in the same blog): mmsba.wordpress.com/2017/05/01/airbus-or-boeing-part-2 $\endgroup$– Cpt ReynoldsDec 26, 2017 at 20:34
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5 Answers
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On a pilot-vs-FBW system perspective, as mentioned in the comments to the question, the most notable difference is the authority priority:
Boeing trusts more the pilots: they can supersede the Fly-by-wire automatic commands by exerting enough force on the controls
Airbus trusts more the FBW system: if the system is fully functional ("Normal law") it will always have priority over the pilots to protect the aircraft and keep it in the envelope, but they still have room for "non-standard" maneuvers, e.g. commanding bank angles between 33° and 60°. The autopilot can be activated and de-activated at will by the pilots, and it sits on top of the FBW envelope protection.
One of the most famous examples where this comparison emerges (and the subsequent debate about which approach is better) is the China Airlines 006 accident. I won't go into detail, there is the accident report that will provide much more information that I can remember, but suffice to say that this 747 was recovered from a quite unusual attitude
As mentioned in the wiki article, the report states that the passengers were subject up to 5 gs during the maneuver and the stress on the horizontal tail surface has been so great that as a result it was damaged:
The usual argumentation goes along the lines that, would this had been an Airbus, the pilots would not have been able to save the aircraft. See for example this PhD thesis at page 184 of the pdf, section 6.2.3 "Pilot Authority at the Boundary":
It is likely that if the aircraft had prevented the crew from initiating control commands that would lead to aircraft damage, the aircraft (and passengers) would have been lost.
The problem with such a comparison? It focuses on the recovery after the unusual attitude was achieved and totally forgets about the sequence of events that lead to it or, to the very least, assumes that an Airbus would have responded in the same way to the preceding events (then why make a comparison at all?)
An honest comparison would take into account this and acknowledge that an Airbus in Normal Law would not enter a spiral dive in the first place, even with an engine out, as bank protection/attitude-hold would prevent it.
answered Mar 25, 2014 at 14:23
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3$\begingroup$ In fact the 33 degrees is limit to which the control system returns after upset to higher bank, for example turbulence. But since with centred side-stick the control computer aims for zero roll rate, it would actually stop the roll after a few degrees (this is well documented behaviour in case of engine failure; banks very slightly and maintains shallow turn until rudder trim is manually dialed in). $\endgroup$ Mar 25, 2014 at 22:04
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$\begingroup$ @JanHudec, yes, I have specified "attitude-hold" for the reason you cite. Feel free to add it to the answer. $\endgroup$– FedericoMar 25, 2014 at 22:07
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$\begingroup$ If I recall correctly, Airbus has a not-very-widely-known Abnormal Attitude Law to allow recovery of precisely these situations where the Normal Law would not be sufficient. I seem to recall it’s mainly a direct control of surfaces. Maybe someone can dig out a proper source other than that obscure corner of my mind... $\endgroup$ Dec 26, 2017 at 20:04
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Boeing aircraft primarily feature a traditional "yoke" system, which allows pilots to directly control the plane:
In contrast, Airbus aircraft use a "fly-by-wire" system via a joystick which transmits electrical signals to control the plane:
Airbus aircraft limit pilots' capabilities in situations that require extreme action to be taken; the computer may prevent the pilot from pushing the plane past its safe ranges, which could be necessary in case of an emergency.
Boeing aircraft leave ultimate control mostly to the pilot.
answered Dec 19, 2013 at 2:00
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12$\begingroup$ "which could be necessary in case of an emergency". It'd be good if you could describe a situation where it would be necessary to go beyond these limits. Also, most newer Boeing aircraft also use fly-by-wire systems, though pilots still use a yoke to control the aircraft. $\endgroup$ Dec 19, 2013 at 3:09
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5$\begingroup$ @Qantas94Heavy I encourage you to write your own answer! We're only at a 1.5 ratio atm. $\endgroup$ Dec 20, 2013 at 17:39
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3$\begingroup$ B777 uses fly-by-wire as well. fly-by-wire v.s. direct hydraulic is a technical detail. The control laws are the significant difference. $\endgroup$ Mar 25, 2014 at 21:59
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2$\begingroup$ @Qantas94Heavy "necessary to go beyond these limits"? You fly out of a cloud and heading straight for you is another aircraft, perhaps 2 or 3 seconds from collision. With a Boeing, you can jerk the controls enough to avoid a collision, even though you may pop rivets and bend metal. With an Airbus, it may not let you make such a dramatic maneuver, to prevent damage to the aircraft. $\endgroup$ Apr 18, 2014 at 19:34
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9$\begingroup$ In laymans terms, in a boeing, the pilot commands. In an airbus, he is just a voting member. $\endgroup$ Nov 19, 2014 at 22:34
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Big difference is on Boeing with a yoke, it is like two linked steering wheels in a car. The pilot not flying can easily see what the other pilot is doing with his controls, as the yoke in front of him moves along with the other pilot's inputs.
On the airbus models with a side stick, the pilot not flying cannot see what the other pilot is asking of the controls. This contributed to the situation where Air France stalled and fell into the sea without the pilot in the left seat realizing that the pilot in the right seat had his controls calling for full pitch up. (The opposite of what would get them out of a stall.)
answered Jan 25, 2015 at 23:33
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4$\begingroup$ Although not as complete as other answers, the fact that a pilot does not see what the other pilot is doing is a very good point to mention. It is also worth noting that in the case of AF447, the autopilot safe envelope protection was disabled when they lost the airspeed sensor. Despite the fact that the sensor went back to normal shortly after, the autopilot had relinquished total control to the pilots (no more safe envelope), allowing the copilot to set the plane in this stalling attitude (the autopilot working normally would never have allowed that). $\endgroup$– HokiMar 27, 2015 at 17:57
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5$\begingroup$ so..it's possible to have total control for the pilots... $\endgroup$– NikkoOct 12, 2015 at 15:11
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Airbus (A320+; A300 and A310 have traditional controls) uses flight control laws. In flight, the side-stick input does not indicate desired position of control surfaces, but desired wing loading and roll rate. The flight computer takes care of trimming the aircraft for straight flight at current speed and balance.
Boeing uses traditional controls, where the position of control column corresponds to position of control surfaces and force on the control column corresponds to force on the control surfaces. This means that the pilot has to adjust the trim manually when not using autopilot.
The Airbus system is more convenient, but it has its disadvantages. The neutral stability means that the aircraft won't tend to maintain speed by changing pitch, so the pilots have to monitor speed more carefully. It really needs the flight envelope protections to be considered safe.
Boeing has flight envelope protections since 777, so that's not a difference any more. I don't think they are adding them to new versions of 737 though.
answered Mar 25, 2014 at 21:57
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$\begingroup$ Airbus has nevertheless a velocity-hold control loop, so velocity will be maintained. The throttle lever while in normal law in cruise only sets the maximum allowed thrust, but it does not fix it in any way. $\endgroup$– FedericoMar 26, 2014 at 13:27
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$\begingroup$ @Federico: That's not part of the control law. It's auto-throttle just like in any other large aircraft and can be disengaged. Of course pilots keep it engaged as it simplifies the handling. $\endgroup$ Mar 26, 2014 at 13:44
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$\begingroup$ Airbusses still have positive stability; they just have slightly-less-positive stability than (e.g.) Boeings. $\endgroup$– VikkiJun 6, 2019 at 2:30
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$\begingroup$ @Sean, I don't think Airbuses have any less natural positive stability than Boeings, but in normal and alternate flight law the control system undoes it, providing a artificial neutral stability. $\endgroup$ Jun 6, 2019 at 5:26
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My 2 cents:
There are a few things mentioned here.
- The sidestick and autothrust systems of the Airbus are different than the conventional yoke and autothrottle system on the Boeing.
- The Airbus technology and quiet cruise was great; the Boeing's tactile feel and crosswind capabilities were very good.
- There is a difference in the length of the fuselage, making taxiing different. The handling characteristics in flight are very similar.
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4$\begingroup$ "Airbus technology and quiet cruise was great" is just an opinion. "There is a difference in the length of the fuselage" is meaningless. Yes, not all planes are the same length. But not even all Boeing 737s are the same length! $\endgroup$ Mar 25, 2014 at 14:09
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1$\begingroup$ @JanHudec the A320's engines are further outboard than the 737's, so despite having more vertical ground clearance, they'd actually strike the ground at a similar bank angle. And in either case, the wing tip would strike first... the engine would be the least of your problems compared to the fact you'd have just sheered/damaged a wing or be cartwheeling/groundlooping down the runway. $\endgroup$ Dec 15, 2014 at 17:20