Aircraft operators and air traffic management stakeholders can make U.S. airspace safer by improving weather reporting protocol and being more diligent about ensuring the right people get clear, consistent data in a timely manner, an NTSB study on pilot weather reports (Pireps) found.

The report, “Improving Pilot Weather Report Submission and Dissemination to Benefit Safety in the National Airspace System,” was prompted by findings in 16 NTSB investigations from 2012 to 2015 that spotlighted areas of concern. In two instances, the Board identified failure to deliver Pireps to flight crews as a contributing factor. In the other probes, the NTSB identified Pirep-related shortcomings but determined they did not play a prominent role in the incidents and accidents.

“The prevalence of these issues across numerous investigations, as well as the similarities between these issues and the concerns voiced by Pirep user groups, suggests that such problems are widespread,” the NTSB wrote in the report, which was adopted on March 29. “The NTSB believes that correcting these systemic Pirep-related issues can help reduce the occurrence of hazardous weather encounters in the NAS.”

Smoother Dissemination Process

The report focuses on three broad themes: pilots need to make more submissions to bolster data quantity; submissions must be more accurate; and Pireps must be turned around and distributed quickly and consistently to be more useful.  

Pireps are filed with air traffic controllers, flight service stations or company dispatchers. The reports are then distributed locally and, in many cases, nationally for use by other pilots, weather forecasters and dispatchers, among others. The NTSB’s findings suggest that the Pirep process breaks down most often at the dissemination stage. The NTSB found issues with distributing Pireps in 12 of the 16 investigations—including 10 fatal accidents—that prompted its study. 

In one case, in March 2012, a Learjet 35A flew through severe icing on approach to Anchorage, Alaska. The windshield iced over and the pilots lost all forward visibility. The aircraft veered off the runway after touchdown and ended up in a snow bank. The NTSB found that 15 minutes before the Learjet flew through the icing conditions, the controller handling the flight learned from a tower controller at Elmendorf Air Force Base, 7 miles away, that an F-16 pilot broke off an approach because of severe icing that coated his canopy.

“The Elmendorf tower controller used good judgment in sharing the severe icing Pirep with the Anchorage facility,” the NTSB said. “However, the Anchorage approach controller did not relay the urgent Pirep to the Learjet flight crew (or the pilot of another aircraft operating near Anchorage), which the NTSB found to be a contributing factor to the incident.”

In August 2015, an Airbus A320 flight crew declared an emergency after suffering a shattered windshield and airframe damage when flying through a hail storm over Nebraska. The Safety Board found that the flight crew had asked en route controllers “repeatedly” for Pireps from the area before heading into the weather, and received none. The Board learned that one Denver en route center controller handling the flight had relevant Pireps but failed to relay them.

In several instances the Board found controllers failed to request Pireps despite reported or forecasted conditions—such as ceilings below 5,000 feet, turbulence, wind shear or icing—that required them to do so. The requirements help, as one survey showed that half of a set of GA pilots do not voluntarily submit Pireps, but “typically respond” when prompted by a controller or flight services specialist.

Data accuracy is another common problem, the NTSB found. In addition to incorrect information, that category encompasses Pireps that are not coded correctly or cannot be read by automated systems within the Pirep ecosystem, and therefore may not get distributed properly or at all. 

“For example, a CWSU meteorologist pointed out that the AWC website, which displays graphical depictions of Pireps information, cannot process Pireps that contain typographical or formatting errors,” the NTSB explained. “Thus, Pireps containing such errors may not be disseminated to the NAS.”

A recent FAA policy change may be adding to the poor data-quality issue. Beginning in March last year, controllers in terminal facilities were required to enter Pireps into the Aviation Information System Replacement (AIS-R) repository instead of passing them on to Lockheed Martin Flight Services, the FAA’s flight service contract provider, for entry. The move, which an FAA memorandum on the changes says was made to cut costs, coincided with an uptick in errors. “For example, urgent reports have been coded as routine, a flight level that translated to '400,000 feet' was reported, and the text elements of some Pireps were transcribed using full words, rather than the abbreviated codes upon which other systems rely for display processing,” the NTSB found.

Cooperative Effort

The dissemination and data-accuracy issues led the NTSB to make five recommendations to the FAA that target the air traffic controller’s role in the Pirep processes. The Board asked the agency to work with the National Air Traffic Controllers Association to review best practices for both soliciting and disseminating Pireps; incorporate real-world scenarios into controller training that emphasizes the value of fair- and adverse-weather Pireps; review and revise controller training to provide two sets of automated tools to help controllers collect accurate Pirep information and import existing data from their systems; and revise internal FAA orders to emphasize Pirep particulars, specifically “coding, handling, solicitation and dissemination.”

Meanwhile, the NTSB identified a clear disconnect between pilots’ views on the importance of Pireps and their willingness to submit them. An AOPA survey found that 83 percent  of pilots viewed Pireps as “extremely or very important” to aviation safety, yet voluntary submissions trend far below this. The Board pointed to several reasons, such as a lack of awareness of filing Pireps that support as-forecasted conditions, and a lack of confidence in the pilot’s ability to judge the weather or follow proper reporting procedures.

Another challenge identified by pilots: the workload involved in submitting a Pirep from the flight deck. Pilots responding to the AOPA survey cited the hassle of having to locate the correct flight-service station frequency and then both deliver the information and validate read-backs from the FSS representative. Part of the challenge is that, unlike controllers, FSS personnel have no information about the aircraft they are talking to, so pilots must communicate basic information such as aircraft type and altitude in addition to the core weather-observation data.

The process “is having an unintended deterrent effect on reporting because some pilots find the process too time-consuming and therefore choose not to submit,” the NTSB said. The Board recommended that the FAA review the process and simplify procedures with an eye to saving time.

As a result, the Safety Board issued recommendations to the FAA, AOPA Air Safety Institute, the Aviation Accreditation Board International, the National Association of Flight Instructors and the Society of Aviation and Flight Educators to improve Pirep-focused training for student pilots, emphasizing their importance as well as when and how to file them. 

The NTSB zeroed in on FAA limitations that excludePireps older than one hour from the submission system. While older reports often have little value in flight planning, they are valuable to meteorologists for forecasting. The Board recommended that the FAA expand the acceptance window by at least several hours.

Another shortcoming identified by the NTSB and confirmed by the FAA: few Pireps are filed during overnight hours. The Board recommended that the Cargo Airline Association, which reaches operators that fly the majority of the overnight flights, encourage more reporting from pilots and dispatchers.

The Board made 19 recommendations in the study. At press time, the Board had not acknowledged receipt of any responses.