Of RAIM ADS-B and CPDLC
Of RAIM ADS-B and CPDLC.
Back in the Stone Ages—circa 1st half of the 20th Century—the globe-trotting pilot had to rely on navigation instruments as primitive as the celestial sextant.
Today, aviation technology has evolved to include some amazing navaids (navigation aids)—many of them now beamed down from orbit.
Let’s explore some of them!
Of RAIM ADS-B and CPDLC
Safety: Paid for in Blood
Sadly, many leaps in aviation safety have come off the backs of tragedy.
The June 30, 1956 midair collision of a United DC-7 and a TWA Lockheed L-1049A Super Constellation over the Grand Canyon shocked the world. No longer were the friendly, open skies so friendly and open.
However, this tragedy ushered in a revolution of aviation safety. The Federal Aviation Act of 1958 gave birth to the FAA (originally the Federal Aviation Agency).
Along with it came a nationwide network of ground-based Radar installations and Navaids, which served the US well for over 60 years.
Of RAIM ADS-B and CPDLC
The GPS Revolution
Once again, an aviation tragedy led directly to a quantum leap in air safety.
In 1983, Russia shot down Korean Air flight 007, after it strayed into Soviet airspace over the Kamchatka Peninsula. Afterward, then-President Reagan opened the GPS system to civilian commercial aircraft use, once completed, to improve navigation accuracy.
In the airline industry, we’ve had GPS approaches for quite awhile now. Indeed, that cellphone you’re holding, and the Nav director in your car are using it as well.
GPS is so precise, that it requires a correction for Time Dilation error brought about by Einstein’s General Relativity!
Of RAIM ADS-B and CPDLC
GPS to RAIM—Another Quantum Leap
The aviation industry is forever looking for “lower minimums.” That is, the ability to land at an airport in crummier and crummier weather.
In short, the lower you go, the more accurate you need to be. This applies to the airplane, the flight crew (special training), and the GPS satellites available.
Enter Receiver Autonomous Integrity Monitoring (RAIM).
Note below the minimums required for a GPS approach to KDEN runway 34L. Note how, with each improvement of accuracy for the GPS (red circled values, from R to L), the flight is allowed to fly lower, thus improving chances of seeing the runway to land.
RNP 0.30, the standard GPS approach value, means the system must calculate an aircraft’s position to within a circle radius of .3 nautical miles. Any higher accuracy requires a RAIM prediction for maximum GPS accuracy.
RAIM needs 24 or more satellites to operate, although a minimum of five are needed for position reliability.
When we may need to fly these lower approaches, on our dispatch release, we will have a “RAIM Prediction window” that will allow us to fly the approach accurately within a certain time frame.
In other words, during a time window we would be predicted to be shooting the approach, the minimum number of GPS satellites will be available to maximize accuracy.
All books available in Print, eBook or Audiobook—including the new Hardcover collector’s edition of The Last Bush Pilots!
Of RAIM ADS-B and CPDLC
ADS-B
While GPS RAIM has improved accuracy to shoot approaches to lower minimums, the “NextGen” system of Automatic Dependent Surveillance-Broadcast (ADS-B) is revolutionizing the aviation system overall.
In addition to the decades-old ground based RADAR system, ADS-B has basically turned all participating aircraft into their own “RADAR Controllers.” Planes talk to each other, alerting each other to their presence, and GPS satellites expand aircraft surveillance far beyond the ground-based RADAR system.
Of RAIM ADS-B and CPDLC
CPDLC
Traditionally, pilots and air traffic controllers have communicated via VHF radio. VHF, however, is limited to line-of-sight. For long-range, overwater ops, HF was used. However, these frequencies change with the turn of the globe and atmospheric conditions, and is notoriously unreliable. Moreover, monitoring the extremely static-y frequency is downright maddening.
CPDLC (Controller–pilot data link communications) has come to the rescue.
Basically, CPDLC is an elaborate, electronic “text/email” system, which allows thorough communication—again, via satellite. Built on top of ACARS (Aircraft Communications Addressing and Reporting System), CPDLC is continually being improved and updated via the Future Air Navigation System (FANS) system.
Of RAIM ADS-B and CPDLC
A Poll—Lemme Know What You Think!
Loading ...More Hemisphere Adventures
Blog Buddy Style!
Folks, one of the greatest delights I get at work is occasionally hearing someone call out, “Hey, Cap’n Aux!”
It’s a rare treat, but oh so fun! I always know that I’m about to meet another one of you, our great blog buddy readers!
Well, this week, it happened to me in London. As I was walking out of our layover hotel to jump on our crew bus to the airport, one of our flight attendants did just that!
FA Paul was part of my crew, and he’s good friends with one of our long time Blog Buddies here, Anthony G!
Today, in addition to being a Daddy soon, Anthony G is also giving birth to a bouncing baby homemade 737 simulator! We’ll have to check back in with him when it’s finished!
This last London was a fun trip as well, cuz we got to see some amazing stuff! First up, our redeye to LHR was the first time I’ve been able to witness the Aurora Borealis (Northern Lights) from the 777!
What’s more, it’s been years since I’ve seen them so vivid.
Here’s a couple shots!
As excited as I am to share the above media with you, I admit that fellow 777 Cap’n and Blog Buddy Mike D. outdid me with his own shot.
Behold, one amazing pic!
One Last Thing...
You’ve probably read the recent headlines regarding a flight attendant who defended the flight by whacking an unruly passenger with a coffee pot.
Well, I’m here to tell ya…
Don't ever mess with our Bad A$$ Flight Attendants!!!
Folks, be sure to chime in on the above poll.
And, if you have ANY comments or ideas for future blog posts, don’t hesitate to contact me, either here on the Comment section, below, or by the social media listed below as well.
Till the next post,
This is Cap'n Aux
Signing Off!
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Of RAIM ADS-B and CPDLC Links
- United TWA Midair wiki https://en.wikipedia.org/wiki/1956_Grand_Canyon_mid-air_collision
- Federal Aviation Act of 1958 https://en.wikipedia.org/wiki/Federal_Aviation_Act_of_1958
- Aviation Archeology Post of Midair https://www.aircraftarchaeology.com/twaunited.html
- RAIM Navipedia https://gssc.esa.int/navipedia/index.php/RAIM
- A Brief History of GPS https://www.pcworld.com/article/461346/a-brief-history-of-gps.html
- RNAV vs. RNP https://www.ifr-magazine.com/technique/rnav-versus-rnp/
- CPDLC Wiki https://en.wikipedia.org/wiki/Controller–pilot_data_link_communications
Cap'n Aux Links
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- Part 2: Stranded in Paradise https://capnaux.com/pilot-of-the-caribbean-part-2/
- The Airline Cockpit in 7 Steps https://capnaux.com/airline-cockpit-7-steps-updated/
- Top 10 Downers of an Airline Pilot Career https://capnaux.com/top-10-downers-of-an-airline-career/
- Top 10 Things to Never Say to a Pilot https://capnaux.com/top-things-never-to-say-to-a-pilot/
- Pilots Protest Covid Mandates https://capnaux.com/pilots-protest-covid-mandates/
- The Post-Covid Future of US Aviation https://capnaux.com/the-post-covid-future-of-u-s-aviation/
- Flying in the Age of Covid https://capnaux.com/flying-during-covid/
- Life of a Test Pilot https://capnaux.com/the-occasionally-exciting-life-of-a-test-pilot/
- WOTR Video: It’s What Pilots Do! https://capnaux.com/word-on-the-ramp-video-its-what-pilots-do/
- Confessions of a Former Airline Pilot https://capnaux.com/confessions-of-a-former-airline-pilot/
- The Making of a European Pilot https://capnaux.com/the-making-of-a-european-airline-pilot/
- Lessons From the Miracle on the Hudson https://capnaux.com/forced-landings-pilot-lessons-from-the-miracle-on-the-hudson-part-1/
