2
$\begingroup$

Disclaimer: I know there are numerous redundancies and the complete failure of navigation and communication system may not be possible. Hence, let's approach this question as a pure thought experiment.


If a commercial aircraft is flying overwater (there are no visual markers visible) and there is complete navigation and communication system failure, can a pilot still bring the aircraft back to a nearby airport?

Also, is there a slimmest possibility that this kind of failure is possible? Say, a complete electrical failure including the backup batteries?

Adding more information:

  • Let's assume commercial aircraft is something like B737, B787, A320, A380, etc.

  • I am not a pilot, so I don't know if most pilots can navigate using stars, but would love to hear pilots' opinions.

  • Stars may be present, and even the Moon may be there. But if you are not anticipating that kind of failure, would an average pilot be aware that what direction the Moon is in?

$\endgroup$
9
  • 2
    $\begingroup$ Are there visible stars? $\endgroup$
    – DeltaLima
    Mar 15, 2023 at 16:56
  • $\begingroup$ You need to define "commercial aircraft". Some smaller older, aircraft will have vacuum driven attitude and directional gyros, plus airspeed and altitude. That would allow an aircraft with total electrical failure to make an emergency descent to visual conditions. You are correct that more modern aircraft have a lot of redundancy, but once all the backup batteries are exhausted you'd be out of luck. $\endgroup$ Mar 15, 2023 at 17:05
  • $\begingroup$ P.S. I would interpret "no visual markers visible" to include stars... $\endgroup$ Mar 15, 2023 at 17:06
  • $\begingroup$ If you said to me you were going to take away all of my flight instruments, gryos, airspeed, altimeter etc, except ONE, what would the one be? Easy. The wet compass. $\endgroup$
    – John K
    Mar 15, 2023 at 17:21
  • 1
    $\begingroup$ That's almost a separate question, but your average pilot cannot navigate by the stars. At least not in the way we define navigation. Best you could hope for is to maintain orientation and a general heading to back up the wet compass. Same for the moon. Keep it where it is, or make a 180 to go back and put it on the other side. $\endgroup$ Mar 15, 2023 at 18:01

3 Answers 3

3
$\begingroup$

For the sake of the IFR/In the blind answer, lets assume that for this question at least the backup attitude and airspeed indicators are working and the pilot can in some capacity fly the plane in the blind if need be.

Sure, as long as your failure does not involve some kind of critical flight system failure that would effect the pilots ability to control the airplane. All aircraft are equipped with a magnetic compass which all pilots are trained to use at some point in the training. Magnetic compass' are pretty simple and generally independent of system failure so they are always available for navigation. You can fly across an ocean with a compass pretty effectively (Lindbergh did it...) and all pilots should have the basic understanding of how to do this.

Historically planes were indeed equipped with a sextant and a navigator to use it but you would be hard pressed to find one on a modern airliner or someone who knows how to use it. That being said it can be done, at one point in history it was the norm. There is even a license you can get to officially be a "navigator" although in the modern era is a bit redundant.

So yes, if you lose GPS, INS, GLONASS, radios, HF radios and all manner of everything you can still fly a plane just fine with a stop watch and a compass.

Heres a good resource on old school navigation which has some great info.


EDIT: As noted int he comments, what if the compass fails? Well you have a few options

  • continue on your present heading until land comes into sight
  • (also noted in the comments) attempt to use a known star pattern to visually reference direction

And if all clocks on the plane fail, start counting your Mississippi's.

$\endgroup$
1
  • 1
    $\begingroup$ @quietflyer If a pilot has a smartphone handy, I would hope they would use it for GPS rather than googling celestial navigation. $\endgroup$
    – Chris
    Mar 15, 2023 at 20:09
0
$\begingroup$

Unfortunately complete electrical failure can (and has) happened: Air Illinois Flight 710. In this flight one engine had a generator failure, and the crew mistakenly shut off the other generator. Eventually the battery failed, and the airplane crashed. Part of the accident report suggested diverting to another airport before the batteries failed.

I would regard getting the airplane to an airport as theoretically possible but unlikely.

$\endgroup$
0
$\begingroup$

This multi-part question contained a question about using the stars or moon to navigate--

Most pilots probably know how to find Polaris, which would be extremely useful, for flight north of the equator, but not too close to the north pole.

The moon (and the constellations of the zodiac) always rise generally in the east and set generally in the west, with "generally" meaning "somewhere between SE and NE, etc, at most latitudes." Are most pilots aware of this? Do they know how to recognize the constellations of the zodiac? Hard to say-- but probably not.

Orion rises with his belt nearly exactly east and sets with his belt nearly exactly in the west. Most pilots probably don't know this either.

Some pilots may have a general awareness of what constellations of the zodiac are due south in the northern hemisphere (or due north in the southern hemisphere) around midnight at certain times of the year, but most probably don't.

The location of a star, or the moon, that is not near the horizon, i.e. has not recently risen or set, is probably not going to be all that helpful to the average pilot. And directly over the north or south pole nothing is rising or setting. So-- it depends on a lot of things, including the pilot's level of knowledge about the night sky, and the aircraft's location, specifically the latitude.

In general I suspect the average pilot would be hard pressed to do much more than find the location of Polaris and understand that that is due north, which is really only useful at low to mid latitudes in the northern hemisphere.

Training in recognizing the constellations is definitely not a part of any pilot training curriculum!

This answer assumes the wet compass is unusable due to failure (or due to the aircraft being very near one of the magnetic poles), and focuses on using the stars to determine heading. If the wet compass still works, then all you need the stars for is for a stable (well, slowly drifting) reference point so you don't have to constantly stare at the wet compass-- any pilot should be able to manage that. Actually determining latitude with any meaningful precision is not going to be possible without a sextant even if Polaris is visible, and accurately determining longitude is going to be impossible without a sextant, navigational tables, and a precise chronometer.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .