# Tag Info

## Hot answers tagged autopilot

30

I assume in your question the autopilot is engaged. When the auto-flight system reaches the limits of its capabilities it simply disconnects. On Boeing aircraft you get a > AUTOPILOT DISC Warning Message on the EICAS and the siren sounds. Now it is all manual flying for the pilots. An example would be turbulence exceeding the auto-flight system ...

15

I am intimately familiar with that incident. The airplane only had FDR recording the left PFD so they don't really know what was showing on the right one based on FDR. The only pitch angle protection is the shaker/pusher. They didn't get that slow. The AP runs off the Flight Director it's selected to. This is normally the FD of the pilot flying.The ...

15

There are many possible reasons for the autopilot to disconnect. The details will depend on the aircraft, but here are the criteria for a Boeing 737 (source: 737 NG FCOMv2 4.20.2 Automatic Flight - System Description): Autopilot Disengagement The A/P automatically disengages when any of the following occurs: pushing either A/P disengage ...

13

You asked about commercial aircraft in general, so I will give an answer from that point of view. Is there any obvious warning when auto-pilot is disengaged? Yes, both visually as flashing lights, and aurally. Furthermore, the lights and tone does not go away until a second confirmation is received from the pilot. For example, pushing the button on the ...

13

The Boeing 737 allows a mode called control wheel steering (CWS). The A320 doesn't. For what is CWS, see: Is it possible to disengage only one axis of a two-axis autopilot? The wording on Wikipedia doesn't emphasize this point; however, the final report does. The pilots may also manually control the aircraft in a normal manner with the control wheel and ...

13

The reason (back in the day) was an envisioned low-cost autopilot ownership in smaller planes,$^1$ but it was a troublesome system as it aged. The first production [Twin Otter] aircraft left the Downsview factory with an option for the Honeywell H-14 autopilot. This system used large pneumatic servos to control the aircraft. This was a popular option at ...

11

It's a perfectly acceptable practice, provided you disengage the autopilot upon reaching minimums and hand fly it the rest of the way. Some manufacturers, like Cirrus, recommend flying a coupled autopilot approach. I won't sit on the fence about this. Learning how to fly coupled autopilot approaches are fine, but I insist all my students learn how to hand ...

10

The quoted explanation about "fail operational" and "fail passive" is correct, in that "fail operational" means the system will continue to function after an failure, and "fail passive" means the system will not misbehave after an failure. The exact number of autopilots required to make this work, however, is debatable; and much depends on how you define it....

9

The question as it currently stands in the headline "How often do GA pilots use the Autopilot approach feature while landing?" is hard, if not impossible to answer due to lack of relevant statistics. As for the matter(s) raised in the body of the question, is and should the autopilot be used on approaches in GA, here's how I see it, plain and simple: You ...

7

As @Bianfable points out in the comments RVSM airspace is a problem but ignoring that for a minute: The question of will they continue? depends on the airlines op-specs. Different airlines will handle this differently and it may very well be handled different on different airframes within an airline. A call to base may even occur but there are lots of ...

7

Generally speaking (not specific to Airbus), what the layman refers to as "autopilot" is actually three logical systems: The Flight Management System (FMS), which figures out where the plane is in relation to the supplied flight plan. The Flight Director (FD), which figures out how to navigate the plane to where the FMS wants it or according to manual ...

6

Since you tagged airbus, I will answer for the A320. The following image from the FCOM shows the FCU (Flight Control Unit) on the glareshield: This is where all inputs for the autopilot are made. The second knob is the HDG OR TRK SELECTOR KNOB, which allows setting a heading. In general these knobs work as follows: To make the autopilot follow the flight ...

6

There seems to be some ongoing research into just that: There is an effort underway to develop a UAV version of the F-16. This would be based on the QF-16, the remotely controlled target version of the F-16. The air force is already in the process of converting 210 retired F-16s to QF-16s and it was noted that with a little extra work the QF-16 could be ...

6

To my surprise, the FAA clause was added in 2006 after the 2004 notice of proposed rulemaking (NPRM) No. 04-11. Three NTSB recommendations were part of the reason, with the earliest from 1992 (A-92-035). (...) autopilot failures that can result in changes in attitude at rates that may be imperceptible to the flightcrew (...) From the NPRM: This proposed ...

5

If your talking about standard rate turns, those are not really practical in large commuter aircraft. As true airspeed increases the maximum turn rate decreases when the bank angle is limited to a comfortable level of less than 30 degrees of bank. So please make this question more specific, which airplane category are you talking about? Usually the ...

5

Nobody knows for sure, but I can give you some facts which may help your decision and conclusions: Technology Commercial* aviation is one of, if not the, most safety centred industry on the planet. Critical failures and excess risk are simply not tolerated - this means certification is long, expensive and exhaustive. Because of the above, it can take a ...

5

Moving the flight controls above a certain threshold will disconnect the autopilot. From the A320 FCOM (1.22.30 Auto Flight - Flight Guidance, emphasis mine): AP DISENGAGEMENT AP1 or 2 disengages when: The pilot presses the takeover pushbutton on the sidestick. The pilot presses the corresponding AP pushbutton on the FCU. The pilot pushes on the sidestick ...

4

Bell Textron filed a patent for retractable vortex generators in 2006. The patent is here. Boeing also filed a patent for vortex generators that extend simultaneously with a leading edge slat here.

4

Definitions provided by the FAA can be found in AC 120-28D - Criteria for Approval of Category III Weather Minima for Takeoff, Landing, and Rollout. From the document we find for Fail Operational: 4.3.2. Fail Operational Category III Operations. A Fail Operational System is a system which after failure of any single component, is capable of completing an ...

4

Like with two human pilots, you want control1 to be explicitly in one hands. With autopilot, it's the same: it should be either autopilot or you. In the case of 'breaching' the normal transfer protocol for whatever reason ("I have control" - "You have control", which in case of autopilot would be the autopilot disconnect button), there are two possible ...

4

Altitude Intervention will start a descent only if VNAV is the active mode (and the MCP altitude is below the current cruise altitude). If you're in Altitude Hold, then VNAV isn't active, and the Altitude Intervention button won't start a descent. On the other hand, Level Change is its own mode, and selecting it (with a different altitude set in the MCP than ...

3

What happens when pushing the ALT INTV button depends on the currently selected mode. You can find a full description from the FCOM in this answer. VNAV Climb: The aircraft will remain in VNAV Climb mode and will follow the profile as programmed in the CLB page on the CDU. Cruise: The aircraft will start an early descent: Early Descent To start an ...

3

From the Approval of Flight Guidance Systems AC-25-1239-1C document: 30. Override of the FGS. a. General. An override of an engaged FGS function is defined as an action taken by the flightcrew intended to prevent, oppose, or alter an operation being conducted by the FGS function without first disengaging that function. b. Autopilot override. ...

3

In all the jets I fly, the autopilot will always bank at 25 degrees. It doesn't worry about standard rate turns. As others have pointed out or alluded to; a standard rate turn with airspeed above 180 KTAS requires larger than comfortable bank angles. The autopilots also have a half bank feature to limit banks to 13 degrees. Most often pilots will use ...

3

The amount of bank is that which is required to achieve the standard "Rate 1" or 2 Minute turn, being 3 degrees heading change per second, which takes you in a full circle in 2 minutes. This is a universal protocol for turns in the IFR world. This varies with true airspeed (the faster you're going the higher the bank angle required to turn at 3 deg/sec) ...

3

In the non-student GA world, I would say not very often. Maybe 1 in 6 approaches as a guess and from personal experience. If a pilot is flying actual IMC, they may fly a coupled approach as a safety measure. Most non-commercial GA pilots will avoid flying actual IMC in most cases as a rule. Some will fly actual IMC, when the conditions are not too bad, to ...

2

I don't think the quote you gave is correct. This might be the case for some aircraft (like the Boeing 777 with 3 autopilots), but not in general. A more general definition is: Autoland systems are normally designated Fail Operational or Fail Passive. A Fail Operational system must have at least two autopilots engaged for the approach. The failure ...

2

From my research on them, when used as a "poor man's slat" along the top of the leading edge, that is, to increase stalling AOA (about 1/3 to 1/2 the effect of a slat) and make the stall more gentle, as opposed to reattaching flow somewhere, the drag penalty of the VGs at cruise speed is too small to be worth the complexity and weight of the sort of under-...

2

Yes, RNAV autopilots can fly a given route automatically. A pilot can disengage and fly by hand at any time during the flight and the flick of a switch.

2

For non FVW airplanes: Yes it will disengage if certain pitch and roll attitudes are exceeded. When it disengages, the controls are "let go" if the A/P was applying an input at the time, and the control column will move to whatever its natural trimmed state is at that time if the elevator is manually operated with trim tabs. If the airplane has ...

Only top voted, non community-wiki answers of a minimum length are eligible