SENTINEL IN THE SKY

[Music] [Applause] the history of civilization is the story of man's tireless never-ending search for that which is always beyond his grasp where's my new golf ball hmm from the very dawn of time man has tried to extend the range of his vision to pierce the unknown to learn what lies ahead the cave man exploring his mysterious world with the aid of a toy [Music] a hardy pioneer pushing westward through the wilderness scanning the distant horizon the Sailor perched aloft in his crow's nest constantly alert to the dangers of the sea that lie ahead so man move forward through the ages reaching out toward new goals ever probing ever seeking ever searching I paid two dollars for that golf ball with the coming of the scientific era man's ability to increase his range of vision grew by leaps and bounds every day brought new inventions new devices all helping him to see better and farther than ever before I'll find it if it takes all night in the field of aviation perhaps more than any other the need to probe what lies ahead is most pronounced pilots in the early days had to depend solely on their own eyesight to bring them safely to their destinations but as instruments were developed their range of vision was steadily increased the gyro compass operating independently of the Earth's magnetic field two-way radio supplying direct contact between air and ground the artificial gyro horizon telling the pilot when his plane is horizontal under blind flying conditions voice radio communication automatic Direction finding equipment enabling a plane to home to any audible signal high-frequency navigational systems and now at last comes the newest and greatest addition to this impressive list radar radar why yes well that's a new one on me I thought radar was strictly military stuff you know for bombers and battleships it was originally but now Pan American is installing radar and it's passenger planes no kidding I bet it's pretty complicated stuff huh not really you see the whole thing is based on the echo principle echo prince as suppose you were on a mountaintop and oh wait I have a better idea let's put you on a mountaintop now would you mind shouting something okay good now let's see what happened the sound waves of your voice traveled out in all directions part of these sound waves hit the mountain and were reflected back just as light waves are reflected by a mirror now suppose we wanted to measure this distance we know that sound waves travel at about 1,000 feet per second so let's ring a bell and count the seconds until the echo returns six seconds which means that the sound waves traveled a total of six thousand feet out and back well the principle of radar is exactly the same but instead of using sound waves we use radio waves high frequency ones called microwaves knowing their speed we can measure distances just as we did with your echo well do radio waves go fast very fast they travel at 160 mm nautical miles per second in other words in the space of a single second a radio wave could go seven times around the world that's traveling this radar stuff must take plenty of fancy equipment you better does airline radar sets consist of five very intricate parts the transmitter receiver the antenna the synchronizer the plan position indicator or scope and of course the control panel the antenna located in the nose of our plane is covered by a fiberglass shell called the radome this shell is transparent to our radar beam the scope contains a tube like that used in television sets and acts as a screen on which we radar picture standard installation provides two scopes one for the pilot and one for the copilot okay so how does it work well let's look at our parts in diagram form the synchronizer generates timing impulses called trigger pulses at the rate of 400 a second these are sent to the transmitter and the scope both at the same moment the transmitter in turn sends a short pulse of radio energy to the antenna this pulse travels from the antenna along a narrow beam at microwave speed the round-trip to an object 150 miles away takes less than one 500th of a single second now let's get back to our scope the scope translates this pulse into electrons which cause a small luminous spot to appear each new pulse is deflected so that a steady flow of them keeps moving to the edge of our screen actually they move so fast that they create the impression of a single almost invisible line which is called the sweep now let's look at our radar antenna see that reflector it's a giant addition of those found in flashlights and it's used for the same purpose to concentrate our beam this makes the beam pretty narrow so in order to get the greatest coverage our antenna turns slowly in a 360 degree circle the sweep on our picture is coordinated with this so that both beams move together what's that dark wedge at the bottom that's the shadow cast by our airplane itself well what happens when the beam picks something up when something appears in our beam the microwaves are reflected back to the antenna then to the receiver and finally to our scope the radar beam and the sweep are so matched that an object picked up by the beam appears in an exact relative position on the scope remember that our sweep line is continually revolving in time with the beam as it passes over the face of the scope it literally it's a picture for the pilot to study our sweep is set so that the aircraft heading is always at the top of the screen now we add a grid for bearings and some rain circles to help in measuring distances and our story is complete well gee this is all pretty interesting but what's the point I mean how much good does it do the pilot of a passenger plane does radar really help him much it helps everybody by giving the pilot eyes that can pierce fog haze smoke and clouds radar helps him get you to your destination quickly and safely with greater efficiency greater saving of time greater passenger comfort it helps the pilot to know his terrain thereby lessening his fatigue and that of his crew it helps warn him of approaching storms so that he can steer clear of them and give you a smoother more enjoyable ride or find a pathway through them saving detours that might cause loss of time what was that you said before about helping the pilot to know his terrain well terrain mapping is one of the main functions of airline radar it's possible to tilt the radar beam up and down which helps to give the pilot a clear idea of the ground ahead of him regardless of the visibility conditions through which he's flying let's look at some actual radar pictures made during a Pan American Airways flight to Panama we're approaching San Blas Point flying over a solid layer of clouds direct vision isn't much help but the first sign of land appeared on our radar scope about a hundred miles out here we see San Blas on the 50 mile range setting 24 miles out and San Blas Point is clearly visible two minutes later we switch to a shorter range for a more accurate distance check San Blas point is now sixteen miles ahead and we're right on course hey the water showed up blank and the land white how come there's a very simple reason smooth surfaces like bodies of water cause our beam to bounce off to be deflected so it fails to return to the antenna and those areas appear dark on our screen land surfaces though have irregularities some small some large but usually enough to reflect the beam back to its source as a result these pulses register on our scope and land masses show up bright when approaching a mountain our radar beam will bounce back from the near side showing brightly on our screen a far side of the mountain which can't be reached by the beam remains in shadow so a radar echo of a mountain peak would look like this now let's take a look at the most important use of radar its ability to map weather conditions our pilots try constantly to give you the smoothest and most comfortable ride they can but a lot depends on the weather now thanks to radar the pilots can see storms long before they reach them and avoid them wherever possible this means more comfort for our passengers and a smoother ride than ever before what do you mean see storms I thought you said radar cut right through clouds through ordinary cloud cover yes but areas with heavy rainfall cold fronts thunderstorms these show up very clearly on the radar scope like this and this and this even hurricanes show up on our screen here's a recent one off cedar Keys mm I'd sure like to steer clear of that so do we and radar makes it easy now let's look at one more device called contour this helps the pilot probe the center of a thunderstorm as well as its outer edges contour reverses the brightness of the echo so that the worst part of a storm shows up as a dark mass inside it like this and this result the pilot cannot only see storms miles away but he can see into them gee I get what you mean now about radar being helpful let's listen to some actual comments by Pan American pilots taken from their reports invaluable use of this equipment provides extra reassurance to the crew lessens the possibility of fatigue radar helped us avoid several storm areas stewardess served all meals right on schedule no difficulties whatsoever I believe radar is almost indispensable on the Lisbon Joburg route makes for tremendous saving in time and a more comfortable flight terrific help in making a landfall approaching Gander westbound radars wonderful our flight was conducted with slight detours passengers enjoyed normal flying conditions and service whereas other flights in the are you were getting plenty of turbulence say yeah you think maybe I can see radar in action sure thing climb aboard that American is always happy to have its passengers visit the cockpit under supervision of course Oh fog I can't see a thing now that was a naked eye but let's take a look at the radar hey we're over the golf course I will head out to sea if you watch you'll catch the coastline yeah there it is clear as a bell just like a map now let's raise our beam and see what the weather's like up ahead hmm there's one of those thunderstorms that's right according to our range markings it's about 30 miles away we can move slightly to the south and avoid it easily hey this is really something never thought I'd be playing tag with the weather oh what's that we're coming to hmm it's a solid squall line stretching for miles things are going to get bumpy we'll have to go around it huh I'll make a detour nope take a look at what our radar shows the storm appears to be solid but you can see that they're actually only three heavy echoes that leaves plenty of clear space in between for us to fly through well that was pretty simple wasn't it saved us a lot of time too and not a single bump from now on it's gonna be more fun to fly than ever now let's head back to your golf course [Music] you enjoy your trip I sure did learn things too it really is a my golf ball wait a minute radar isn't quite that good at least not yet [Music]