“NORDO” – 5 tips for avoiding loss of communication

5 min read

NORDO is defined as an aircraft that can’t or doesn’t communicate by radio.

“NORDO” is a term defined in FAA Order 7110.65 (a.k.a. Air Traffic Controller’s Handbook) as an aircraft that can’t or doesn’t communicate by radio.  While the term can apply to an aircraft not certified with an electrical system (radio) or one that has suffered an equipment failure, it’s more commonly related to an inadvertent loss of communication. Whether a missed radio call/handoff, volume mishap, intercom snafu, or simply having flown out of transmitter range, the situation can have serious consequences especially on an IFR flight.

While I’m not able to support with scientific evidence, in my personal flying, it sure seems like I’m hearing more frequent occurrences of ATC searching for NORDO aircraft. This can be everything from repeated calls on an assigned frequency, open calls looking for aircraft on the emergency “guard” frequency (121.5), and direct requests for other aircraft to rebroadcast ATC transmissions to effectively extend transmitter range. Whether you’ve been witness to the same activity, or even caught up in a lost communication scenario, there’s likely additional steps we could be taking to cut down on the confusion, effort, and frequency congestion that results from the loss of communication.


Controllers are trained to use all appropriate means available to reestablish communications with NORDO aircraft.

Controllers are trained to use all appropriate means available to reestablish communications with NORDO aircraft. This can include using previously assigned frequencies, emergency frequencies, NAVAIDs, personal or company contact information provided in the flight plan, etc. But bear in mind, this effort takes time and resources and take controllers away from the task of working other air traffic. And in the case that communications have NOT been re-established with the suspect aircraft after just five minutes, the Controller’s Handbook indicates the controller should consider the pilot’s activity to be suspicious which would require a report to a supervisor and on up the chain of command.

While there is some discretion on when the five-minute clock may actually start, in the event that handoffs to other controlling sectors or facilities are missed, or other aircraft are forced to be diverted away from the NORDO aircraft, a report is most certainly forthcoming. The occurrence report may eventually make its way to the local FAA FSDO office who would have responsibility for investigating to determine whether a pilot deviation occurred. And the rest is not pleasant. An ounce of prevention is worth a pound of cure as they say, so consider these five tips to keep you out of communication jeopardy.

1. Listen up! Easier said than done with the myriad of distractions that can be found on the flight deck. From advanced avionics to streaming music to needy passengers, distractions lurk. Remember the primary task at hand and not only commit to your own sterile cockpit rules, but encourage your passengers to take an active role in listening up on frequency for your tail number which will also prompt them to quiet down during the communication exchange. All quiet? Check your volume, recheck your frequency, and be alert to the possibility of a stuck mic.

2. Mind the volume (and squelch). On a busy frequency while attempting to concentrate on another task, or simply enjoy some solitude, it’s easy to be tempted into turning down the volume. Is your music being interrupted by garble on a distant frequency or frequency bleed over? Maybe you’re tempted to close the squelch. Engaged in a deep conversation with your passenger or instructor? Another tempting moment for a quick volume adjustment. All of these scenarios, however, make you susceptible to lost communication. Avoid the temptations and make sure all aspects of your communication radios are set before takeoff and periodically checked while enroute.

3. Monitor guard. The standby radio is available for more than just a backup or obtaining your IFR clearance. If you’re not already in the habit, always monitor the emergency frequency. 121.5 or “guard” is generally the first alternate frequency ATC will use in attempting to contact a NORDO aircraft. Further, if all pilots dutifully monitored guard, we’d have the opportunity to pick up an ELT broadcast, another aircraft in distress, and even help other pilots locate the appropriate frequency. As soon as you’ve left the terminal environment, tune in 121.5, monitor comm 2 through the intercom, and make sure that volume is up.

4. Ask for a radio check. Has the frequency gone mysteriously quiet? While a quiet frequency is not uncommon, if the change was abrupt, that’s a warning sign of a communication issue. Even on a quite frequency, if the silence continues for an extended period (5-10 minutes perhaps), a radio check may be in order. ATC would rather respond to a radio check than track down a NORDO aircraft, so error on the side of caution. Another option in advance of a radio check, or in concert, is to open the squelch on your radio to ensure range is not the issue. And then check using your backup comm radio. If range is suspected, likely there is another transmitter the controller has access to and you may ask for an alternate frequency or move to the step of locating an alternate frequency.

5. Anticipate frequencies. If you’re accustom to flying the same routes, you may have many of the communication frequencies memorized, but many of our modern, installed navigators are equipped with frequencies that you may attempt. Additionally, the enroute chart, chart supplement (A/FD) can be used to locate frequencies. Focus more on establishing contact with a facility (any facility) as opposed to the correct frequency. Timeliness in reestablishing communication is critical. Tools that controllers have at their disposal should make it reasonably easy to identify your correct frequency assignment or at least make a reasonable suggestion based on location.

Eric Radtke