Flight AF447 (Air France A330 mid Atlantic crash) - official BEA animation - illustration of information contained in flight report including flight inputs, airspeed, warnings etc.
CPDLC employs a series of standardized text messages for most routine communications. These include over 200 “uplink messages” (from ATC to the cockpit) and more than 100 “downlink messages” (from the flight crew to controllers). Pilots and controllers also have the option of sending
free-text messages. For the most part, CPDLC works with the click of a mouse. Controllers have drop-down menus on their screens with the standard messages. Menus are divided into different categories to make the appropriate message easier to find. Each ACC can modify their drop-down menus and choose which messages are contained in each message group.
For instance, the Maintain (Alt), Climb to and Maintain (Alt), Descend to and Maintain (Alt), and At (POS) Climb to and Maintain (Alt) would likely go under the Altitude drop-down menu. Other common drop-down menus are Radio, Route, Speed, and Free text.
There are also quick-response buttons for Unable, Roger, Negative, Standby and Deferred.
For downlink messages that require a response, the controller just has to click on that message and the appropriate drop-down menu, and the response is highlighted in green (as opposed to white), making the messages easier to find.
Usage and Equipage
The number of monthly CPDLC contacts in domestic airspace has almost tripled in the 14-month period from November 2012 to December 2013: from just under 18 000 to nearly 53 000. Those numbers are expected to continue to rise as the CPDLC equipage rate increases. The percentage of CPDLC-equipped flights in Canada’s domestic high level airspace varies according to geographical location, from 27 percent in the central Canadian FIRs, to 79 percent near the country’s east coast.
In addition to the many safety enhancements, CPDLC adds an important efficiency benefit. As the need for voice communications decreases, the problem of radio frequency congestion becomes less of an issue. CPDLC also has a multiplier effect on alleviating frequency congestion when you calculate the number of flights using CPDLC. If one data link message can eliminate even 30 seconds of airtime, that can translate to 15 or more hours per day of voice communications
taken off the airwaves.
And finally, for those of you who are wondering about the safety of pilots “texting while flying”, it is always the pilot monitoring (PM) who sends and receives the messages.
The state in which the possibility of harm to persons or of property damge is reduced to, and maintained at or below, an acceptable level through a continuing process of:
LNAV is a non-precision approach. It uses GPS and/or WAAS for lateral navigation, but there’s no vertical guidance. Typically it takes you down to 400 ft.
LNAV/VNAV again is a non-precision approach. It provides lateral guidance from the GPS or WAAS receiver and vertical guidance from a barometric altimeter or the WAAS. Without WAAS, you must have a VNAV altimeter. Decision altitude is typically around 350 ft.
LPV? LPV is a non-precision approach. It stands for Localizer Performance with Vertical Guidance and uses the WAAS GPS only. It is the most desired approach that you can be offered. It typically takes you down to 200-250 ft decision height.
LP. It is a future approach that will use the high precision of LPV for lateral guidance, and a barometric altimeter for vertical. Runways where obstacles or infrastructure limits are, vertically guided approaches cannot be published.
LPV Operational Benefits
Currently over 1,975 runways across the United States and more to come. Many approaches have minimums to 200 ft height above touchdown and ½ mile visibility with greater accuracy and consistency.
Once you’ve flown a GPS approach with LPV you’ll be amazed at how the aircraft performs and how stable it is. Electronic glide paths eliminate intermediate step down approaches, or dive and drive approaches. This type of approach provides more comfort for your passengers, less ear popping, and just more comfort and safety overall. The glide path become independent of ground or barometric equipment. Everything is calculated internal to the aircraft.
WAAS and LPV eliminate:
cold temperature effects,
incorrect altimeter settings,
and lack of local altimeter source
If I install WAAS-capable equipment, am I ready to fly LPV approaches?
Questions that we’re often asked are if I install WAAS-capable equipment, am I ready to fly LPV approaches? The answer is no. WAAS receivers cannot be installed under a straight field approval. There’s a lot more to the field approval process. Once it’s installed in the aircraft, the installing agency needs to make sure that all equipment in the airplane is properly functioning. That means the autopilot, the scaling, everything that becomes a part of this equation needs to be checked, so it’s a lot more stringent than a straight field approval. Most WAAS receivers are installed under an STC.
WAAS-capable avionics do not automatically mean that you can fly to an LPV minimum. To accomplish the LPV minimums, you need dual WAAS receivers. They must be certified under TSO 145/146.
Can I upgrade my existing navigational system to a WAAS receiver?
We’re often asked the question can I upgrade my existing navigational system to a WAAS receiver and the answer is no. Current systems are certified under TSO C129, a completely different criteria. TSO C145 and 146 means that the units are certified as a standalone receiver. No other signal needs to go into that box in order to give it the accuracy that it will present on your aircraft instruments.
It also requires an antenna change. The antenna’s are different from the TSO 129 box to what’s certified on a 145/146. Installation is currently being done by STC and requires:
dual GPS receivers,
other equipment mods, such as the scaling and autopilot,
annunciation, whether it’s external or on an EFIS system,
and a flight test procedure are all required.
Airports with WAAS approaches
This map shows some of the airports (see presentation slides) that are across the United States.
The WAAS/LPV Approach Plate
The LPV approach on an approach plate is called out (see presentation slides). You’ll see that it says “WAAS Approach” on it. So just like any other approach, GPS approach, VOR approach, ILS… it calls out particular criteria. So you take the approach appropriate to that airport, channel it up in your receiver and fly the approach.
July 1, 2010 - Gary introduces the video series with a brief overview of key topics to consider if your aircraft isn't equipped with WAAS, including legacy interface problems, field approvals, annunciators, Next-Gen criteria, and how to determine if your aircraft is a candidate for an upgrade.
July 8, 2010 - Find out how WAAS is a part of the FAA's Next-Gen initiative, the system network and coverage, and why installing WAAS-capable equipment doesn't mean you're ready to fly LPV approaches..
July 22, 2010 - Learn how WAAS changes navigational system accuracy, approaches, flexibility, precision, fuel savings and government and airport costs. Operational benefits and Next-Gen considerations are also discussed.
The UPS A300 crew flew a nonprecision approach to Birmingham’s Runway 18.
October 1, 2014, 4:40 AM
It could have happened to any two professional pilots flying a nonprecision approach, in darkness, into weather that turned out to be worse than they expected after a night of back-side-of-the-clock flying. But the NTSB’s September 9 hearing into the Aug. 14, 2013 crash of UPS Flight 1354, an Airbus A300-600, on approach to Birmingham, Ala. (BHM), proved that even crews flying heavy jets can lose situational awareness and get just as far behind on nonprecision approach as King Air crews, especially when a handful of other factors also come into play.
The A300 is an early semi-glass-cockpit airplane employing both a primary flight display (PFD) and a navigational display in place of the traditional mechanical attitude indicator and horizontal situation indicator (HSI). The remaining cockpit instruments are round analog displays.
The NTSB determined the probable cause to be the crew’s continuation of an unstable nonprecision approach, as well as the its failure to monitor altitude, an especially critical element in the absence of an electronic glideslope. Based upon its investigators’ findings, the NTSB developed 20 recommendations from the accident–15 directed to theFAA, two to UPS, two to the Independent Pilots Association (IPA) and one to Airbus.
About the Crew
Records showed that the captain, who had approximately 6,400 hours of flying time, 3,200 of them in the A300, had stumbled slightly during earlier training events in his career, although nothing major enough to consider him unsafe when measured against thousands of other pilots. In July 2000 he began training to upgrade to the left seat of the Boeing 757 from the right seat of the Boeing 727. He voluntarily withdrew from that training, saying he felt “overwhelmed,” and returned to the right seat of the 727. He did successfully transition to the right seat of the A300 in February 2004 and on to the left seat of that same type in May 2009.
During a September 2009 training session, he incorrectly loaded an FMS waypoint that was corrected by his first officer. During the same session, the captain “got a little behind on the [localizer] approach…started down a little late,” according to the UPScheck airman, who also indicated that he had difficulty executing a missed approach once he recognized an unstable approach. During a supervised GPS approach conducted in his early line flying, the captain was, however, marked down for “flying below minimums” and reportedly had difficulty with a crosswind landing touching down “way left of centerline.” While his upgrade was successful, recurrent training records from June 2013 showed a deficiency with nonprecision approaches when he incorrectly set the minimums bug on his altimeter.
The first officer had logged just over 4,700 hours total time (403 of them in the A300), and her records indicated only one issue during A300 initial in June 2012; it read “confusion on the mechanics of the profile mode” during a nonprecision approach, although the event was eventually conducted to a satisfactory level. Both pilots had been flying during the middle of the night, but reviews of the first officer’s personal electronic devices showed she knew she was operating with a sleep deficit on August 14 yet took no action to call in fatigued.
The Birmingham Arrival
UPS 1354 was dispatched from Louisville in the early hours of August 14, its crew unaware that the BHM weather they had received with their dispatch release was missing a forecast ceiling. At arrival time the ceiling was forecast to be 400 feet, below minimums for any nonprecision approach. For an unknown reason, UPS also removed the remarks section of the pilot’s weather data that warned of variable ceilings between 600 and 1,200 feet at arrival time. Even the BHMATIS lacked the remarks about a variable ceiling. That the crew expected to break out of the overcast at 1,000 feet agl was only the first in an unfortunate chain of events.
The crew was aware that BHM’s longest precision approach runway, 6/24, was closed for construction that morning until 5 a.m., three minutes after the time of the accident. Upon arrival in the BHM terminal area, the captain, the pilot flying, used the autopilot to command the aircraft as ATC vectored them for the Runway 18 localizer approach, which specified a 1,200-foot minimum descent altitude (MDA). With a reported ceiling of 1,000 feet, the crew expected about a 700-foot safety margin to locate the runway when they broke out of the clouds in the darkness. Runway 18 provided minimal lighting, just traditional runway edge lights and runway end identifier lights (REIL).
Once on vectors, the Board reported, the first captain should have commanded the FMSbe switched from nav mode to approach, for proper sequencing, but he was apparently distracted by a short conversation from the first officer about other runway options and forgot. Despite a displayed “discontinuity” message, the FMS was never correctly sequenced, which left the autopilot unable to capture the approach and generate an internal glideslope to assist the crew on the way to the MDA using the more common continuous descent final approach (CDFA) method. Although the first officer verified the approach, she did not notice the non-appearance of the computer-generated glideslope that would have avoided the traditional, less stable nonprecision technique of diving for the MDA that was eventually employed.
The A300 crossed the final approach fix 200 feet high and was slowing to final approach speed when the captain became aware something was wrong and switched autopilot modes to vertical speed, first requesting a 700-fpm descent, but quickly increasing that to 1,500 fpm, in violation of UPS stabilized-approach criteria. He also did not mention the mode change to the first officer, who was occupied with the before-landing checklist. Thirty-nine seconds before impact, the captain mentioned that the airplane was “way high,” although in actuality it was not.
The enhanced ground proximity warning system (EGPWS) on UPS’s A300 fleet, while technically compliant, did not operate exactly the same way as the systems aboard otherUPS aircraft. The industry standard “500” foot callout was disabled, as were the final 100-foot increments and even the “minimums” callout. The A300 system also did not include a free Airbus update that would have offered the crew an earlier alert 6.5 seconds before the crew heard their first warning. During the approach, the first officer made the required “1,000” foot call but failed to make any other callouts, including when the aircraft reached the MDA.
The A300 passed the imtoy fix–two miles from the end of the runway–at close to the correct 1,380-foot prescribed altitude, but still descending at 1,500 fpm. The aircraft passed through minimums with no callout from the first officer, who also did not mention the high rate of descent. At about 300 feet above the ground, the EGPWS called out “sink rate,” after which the captain reduced the vertical speed to 400 fpm. At about this same time, the aircraft broke out of the clouds, later estimated at 350 feet agl, rather than the 1,000 the crew expected. As both pilots called the runway in sight, the captain disconnected the autopilot just one second before the aircraft struck the first line of trees north of the airport. The CVR continued for nine more seconds and recorded a “too low, terrain” warning one second after initial impact.
If Only …
During the September 9 Q & A session, NTSB member Robert Sumwalt commented on the more current EGPWS software upgrade that Airbus encouraged operators to install. “If a newer software version had been available it would have sounded 6.5 seconds earlier and 150 feet higher. But with the excessive rate of descent, I’m not sure this would have prevented the accident. [But] it would have given the crew the opportunity to avoid this crash.” Also mentioning a 2010 IATA-published safety article about ground prox, Sumwalt said, “To get the most CFIT risk reduction possible, the airlines need to give GPS position direct to the EGPWS unit, which UPS did not do, and to keep the latest software and database up to date, which UPS did not do.”
Sumwalt said the system’s TSO requires the 500-foot callout be installed, but not that it be activated. “That’s like requiring seatbelts in cars, but not requiring people to use them,” he said. “Everything UPS does is about efficiency, with people running around with stopwatches and clipboards in case an airplane is a minute late. The sad thing is that we have a layer of defense that could possibly have prevented this accident. If you’re interested in efficiency, I can guarantee you those August 14 packages did not get delivered by 10:30 a.m.”
AIN asked UPS to comment on Sumwalt’s position that the A300 EGPWS software does not include all of the latest updates. UPS responded, “Our ground proximity system wasFAA-compliant. It’s also important to understand that the NTSB could not determine if a newer version of the software would have made a difference. Going forward, however, we are upgrading this system. While we can’t know if it would have made a difference this time, it could in a future incident.”
The company also commented that it is implementing a series of safety enhancements in response to issues raised by the investigation.
UPS Safety Enhancements
• training and standards enhancements on automation, callouts, pilot monitoring duties, stabilized approaches and no-fault go-arounds
• enhanced meteorological information available to crewmembers
• adoption of ICAO’s LOSA (Line Operations Safety Audit) program
• new standards for flying into Birmingham in darkness
