Flying a plane by sound alone

[MountainBear]

Cattletruck has an interesting suggestion in this post. (http://www.pprune.org/showthread.php?p=5920957&posted=1#post5920903)

His suggestion is simple: in case of smoke in the cockpit have all the instrument data fed audibly into the flight crews headset. Let them fly the plane with their eyes closed.:ooh:

Does anyone have any thoughts on the safety aspects of that suggestion.

[ATCast]

Interesting idea. But feedback by sound alone will easily overload the human capacity to process all that aural data. However, if you use haptic feedback (e.g. pressure on the control column/ sidestick) to give attitude information to the pilot, and aural information about altitude, heading and speed, it might be possible to fly blind.

[safetypee]

Several aspects of the ideas above were researched at RAE Bedford in the late 1970’s by the aptly named Blind Landing Experimental Unit (BLEU).

The focus of the work was to replace the flight director / autopilot during the approach and particularly the landing flare. Most ideas were pure research, but some were associated with the Economical Cat 3 Programme which looked at low cost autopilots and manual reversion for flight in fog.
The pitch channel was considered first, and then only with some success, the roll channel added; I don’t recall flying both together. All of the work was in simulation, except some follow-on aspects of voice warning during low level flight were tested in a Sea Vixen and Gnat aircraft. I think that this or a similar system was used by the Jaguar force.

Some tests were based on the Naval audio ADD fast/slow system using tones or pulses for up/down commands. The approach guidance was reasonable, but the flare was distinctly interesting; all aspects depended on autothrottle.
The flare tests were also associated with open / closed loop tests to determine the minimum instrumentation required for head down landing – what information was essential. Head down FD flare and landings were flown in an HS 748 and BAC 1-11.

A haptic system based on a knife edge in a single control stick was interesting, again producing reasonable approach performance (pitch only), but with mixed results in the flare. It lacked sensitivity and speed of response. IIRC this was mixed with audio altitude, a tone change during the flare which came from the closed loop testing above.

AFAIK the work was not followed up as more viable solutions were found which used LED glareshield mounted paravisual directors and LED windshield HUDs. At that time, none bettered a conventional HUD due to technology limitations, although the single-eye monoHUD was flown with success. This work progressed to become the modern helmet mounted displays.

I think that even with modern technology, the limiting factor is the human and the dominant sensor – the eyes.

[Tee Emm]

We used the sound of the wind through the wires in Tiger Moths. Nostalgia? Sure but good experience. Sorry - nothing to do with the serious nature of the initial and subsequent posts :ok:

[Tmbstory]

Tee Emm:

The wind in the wires, sure did.

Also the high wing Cessna fleet could be flown by listening to the centre of pressure moving , through the ventilation system in the wing root.

Tmb

[Kerling-Approsh KG]

A great reason not to use the auditory channel is that it shuts down very early on as the individual becomes overloaded. However...

Some years ago, I had the great pleasure to try out NASA/USN's TSAS. Simply, it consisted (then; it may have changed) of a pad installed on the pilot's seat and a waistcoat, both connected to a small pneumatic system.

ABSTRACT:

Pilots and astronauts do not experience spatial disorientation in normal day-to-day terrestrial activities. On the ground, the perception of position and motion is determined by central nervous system integration of concordant and redundant information from multiple sensory channels (somatosensory, vestibular and visual) which collectively yield veridical perceptions. In the acceleration environments experienced by pilots and astronauts, the somatosensory and vestibular senses frequently present false but concordant information concerning the direction of gravity or down. When presented with conflicting sensory stimuli, it is normal for pilots and astronauts to experience episodes of disorientation. Visual instruments and displays developed over the past 70 yr have not solved the problem. A simple solution to maintain spatial orientation is to provide true information using the same sensory channels we use so successfully on Earth.

METHODS:

The Tactile Situation Awareness System (TSAS) developed by NASA and the U.S. Navy uses a matrix of mechanical tactile stimulators (tactors) applied on the torso and limbs to convey orientation cues (e.g., gravity vector) in an intuitive fashion to the skin. A series of in-flight experiments to validate and test a variety of tactile displays and concepts has been carried out in both helicopters and fixed wing aircraft.

RESULTS:

Pilots were able to fly complex maneuvers with no instruments or outside visual references (blindfolded) with less than 20 min of training. Recovery from unusual attitudes solely by tactile cues was trivial. Lab tests have shown the TSAS improves performance under conditions of high workload.

CONCLUSIONS:

When orientation information is presented via intuitive tactile displays spatial orientation is easily maintained in altered sensory conditions including unusual acceleration environments.

I'm extremely wary of anything which might turn out to be snake oil. However, in very little time, I was able to adapt to the TSAS system and, for example, hold a very steady hover in simulated white-out conditions (at the time, I was not a regular rotary wing pilot, either, and I was not at all familiar with the US Navy helicopter type concerned). Other exercises involved transitions, unusual attitude recoveries, approaches, and some battlefield manoeuvres.

How does it work? Select the mode you desire, for example a six feet hover, and the equipment provides tactile cues to achieve it. If low, the pad on the seat taps the pilot's posterior at a rate proportional to the deviation; if left of hover position or drifting left, the left side of the torso receives a similar cue, etc.

Our tactile senses are enormously overlooked in flight deck design. Not for nothing is the 'seat of the pants' so frequently referred to in early literature...

Google, and some professional subscriptions, will find you much more.

[Genghis the Engineer]

There have been a few instances of blind people successfully flying simple aeroplanes - in one case around the world with a suitably qualified safety pilot. I also know a (microlight) flying instructor who a few years ago managed to taxi out, fly a circuit, land and park - blindfold with again a suitable "grown up" in the other seat providing instructions all the way.

However, I think that this perhaps misses the point slightly concerning a more complex aeroplane. The aeroplane can be allowed pretty much to fly itself - the main workload is in operating systems: and that does require a high level of interaction with screens, controls and checklists.

On the other hand, Typhoon for example does operate a large proportion of systems through voice control and simple switching on the stick. An airliner isn't appreciably more complex than a modern fighter, so the potential is certainly there.

But compared to the relatively simple design problem of providing a smoke hood, oxygen mask and extractor system - I can't honestly see the benefits for emergency use alone. Bringing such systems on board to reduce workload in normal use however, and then making them available in emergencies - well maybe.

G

[Treg]

A few years back I had a medical from a former test pilot, then doctor, who had undertaken trials to improve a pilot’s ability to withstand ‘g’. This gentleman was one of the most the unassuming individuals I have met. He casually described the trial he had been involved in that, all of a sudden, took a turn for the worse.

“…the seat had been modified so that we could be in a more horizontal position, but this meant we couldn’t see. So they had arranged a series of mirrors for me to use, which was all going well until they collapsed rendering me effectively blind. To make matters worse there was no ejection capability, so with the aid of a colleague in another aircraft I completed a far from perfect landing…”

He was describing this as he completed a final assessment on my eyes using a slide-rule type device he placed on my lip and extended it away asking me when I had it in focus,

“You will need glasses when you’re forty-three (he was only out by a few months). Oh, if there is a chance to come out winching with you chaps I would really appreciate the opportunity…”

At around seventy he did go with us, a night sortie to a confined area where he accompanied the stretcher. They don’t make them like that anymore.

[Yellow Sun]

Audio orientation is an interesting area especially when coupled to a lack of visual cues. My experience in it is not aviation related, I coach blind rifle shooters. The system employs a light meter (looks like a telescopic sight) mounted on the rifle that is aimed at an inverse target (white in the centre shading to black at the edges) that has a narrow beam spotlight focussed on the centre. The shooter hears a tone through earphones that rises the brighter the light detected.

http://www.flickr.com/photos/41003466@N00/2663857352/

The results that blind shooters can achieve are quite remarkable, approaching those of sighted shooters, and I could easily imagine a fairly simple audio system that would enable pilots to maintain reasonably straight and level flight. However to achieve any significant manoeuvre might prove very difficult. The question is, is it worth the cost and effort developing a system that might be of limited use on an extremely small number of occaisions?

I recall watching an excellent SAS training video depicting an actual DC9 in- flight smoke/fire incident. The crew that had dealt with the incident provided the commentary and acted their parts in the simulator shots. the FO had to read the QRH with the aid of a torch whilst held it right in front of his goggles and the Captain had to employ a similar technique as he leaned forward to see the attitude indicator. An audio system might have assisted PF but would still have left PNF with his problem. On balance I have to take the view that although audio information might help in these situations (and we are assuming that the autopilot is not available) a limited/backup/secondary autopilot would be a better option.

YS

Sorry, don't know why the image is not displaying, but there is a good link to an Austrian site here:

Burgis Site (http://www.burgis-welt.at/Schiessen/gewehr.htm)