What is FAR 91.185?
Federal Aviation Regulation (FAR) 91.185 outlines the procedures pilots must follow when two-way radio communications fail during Instrument Flight Rules (IFR) operations.
The regulation’s approach hinges on prevailing weather conditions. If a pilot encounters Visual Flight Rules (VFR) conditions, they should continue under VFR and land at the earliest opportunity.
In IFR conditions, pilots must follow specific route and altitude procedures:
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Route: Maintain the last assigned route. If being radar vectored, proceed directly to the fix, route, or airway specified in the vector clearance.
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Altitude: Fly at the highest of the following three options:
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The last assigned altitude.
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The minimum altitude for IFR operations.
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The altitude ATC advised to expect in a further clearance.
These procedures are mandatory, yet the regulation allows pilots to exercise emergency authority when strict adherence might jeopardize safety—balancing between operational predictability and situational flexibility.
Procedures to Follow When Communication is Lost
During final approach, trigger lost communication protocols when transmissions cease for:
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60 seconds while being vectored.
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15 seconds on an ASR final approach.
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5 seconds on a PAR final approach.
If attempts to restore communication fail, execute the published Instrument Approach Procedure (IAP).
The standard procedure—commonly known as the “book answer” for lost communications—follows a methodical sequence: continue to your clearance limit, establish a holding pattern over that point, then proceed to an Initial Approach Fix (IAF) and execute an approach timed to arrive at your Expected Time of Arrival (ETA).
Preparation is essential. During pre-flight planning, review designated lost communication routes and altitudes for your flight path. Understanding these procedures is fundamental to both flight safety and regulatory compliance.
Re-establishing Contact with ATC
If communication is lost, your primary goal is re-establishing contact with ATC. Begin with a systematic equipment check: verify volume settings, secure headset connections, and switch to a backup radio if available.
If equipment checks don’t resolve the issue, attempt to relay messages through nearby aircraft—fellow pilots can serve as vital communication bridges between you and ATC.
Aircraft equipped with data link capabilities can utilize text-based systems like Controller-Pilot Data Link Communications (CPDLC), which provide a text-based alternative to voice communication. Within ground station range, direct cell phone contact with ATC can be effective, though this should only be attempted when workload and flight conditions permit safe operation.
Upon restoring communication, deliver a succinct report to ATC detailing when contact was lost, the actions you took, and any deviations from your clearance. Complete post-flight incident documentation as regulations mandate.
When communication fails under IFR conditions, navigate according to your most recently assigned route from ATC. This predictability allows controllers to anticipate your trajectory and preserve aircraft separation.
Should communications fail while receiving radar vectors, proceed directly to the fix, route, or airway specified in your vector clearance. For example, if ATC’s last instruction was “Vector to BRUNO intersection, expect direct CHARLIE VOR afterward,” you should fly directly to BRUNO and then continue to CHARLIE without waiting for further clearance.
Immediately set your transponder to code 7600—this universal signal alerts controllers to your lost communications status, enabling them to provide enhanced separation for your aircraft.
These standardized protocols reduce risk by maintaining predictability during challenging circumstances, allowing the air traffic system to accommodate your flight safely.
Post-Incident Procedures After Regaining Communication
Upon restoring communication, promptly notify ATC. Deliver a brief report covering the outage duration and, when determinable, its underlying cause.
Stand ready to detail your actions throughout the communication gap, including the procedures you followed, your route selections, altitude decisions, and any deviations you made from your original clearance. This helps ATC understand your flight path during the silent period and ensures proper separation was maintained with other aircraft.
Following immediate reporting obligations, comply with any fresh clearances or instructions from ATC. These may include altitude changes, heading adjustments, or route modifications to integrate you back into the normal flow of traffic. Following new instructions carefully is important, as the controller may need to reorganize traffic.
Document the incident thoroughly post-landing. This typically involves an entry in the aircraft’s maintenance log and may require filing an Aviation Safety Reporting System (ASKS) report.
Conclude with a comprehensive post-flight review, asking critical questions to prevent recurrence:
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Was the radio failure preventable?
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Were all lost communication procedures followed correctly?
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Were there any missed warning signs?
This review provides important learning opportunities that sharpen future preparedness.
Learning from Lost Communication Scenarios
Examining historical lost communication incidents during IFR operations provides important preparation insights. Looking at real cases where pilots experienced radio failures, we can identify common causes, effective responses, and potential pitfalls. These studies reveal patterns that enable pilots to forge more resilient mental frameworks for handling similar emergencies in their own flying careers.
A consistent theme is the importance of procedural adherence—particularly those outlined in FAR 91.185. Pilots who successfully navigated lost comes situations typically demonstrated thorough knowledge of these regulations and applied them correctly under pressure. In contrast, incidents yielding unfavorable outcomes frequently featured procedural deviations, showing how important following procedures becomes when communication breaks down.
Situational awareness is another key success factor. Pilots who maintained awareness of their position, terrain, weather, and other traffic were better equipped to make sound decisions during communication failures. This encompasses grasping the broader ATC operational environment and anticipating how controllers might be working to accommodate your silent aircraft within the traffic flow.
Using backup communication methods effectively often makes the difference. Pilots who quickly transitioned to alternative frequencies, utilized handheld radios, or successfully employed non-verbal communication methods like transponder codes often minimized the duration and impact of the communication loss. These cases show how important it is to mastering all available communication resources and their proper operation.
Dedicated training and simulation exercises targeting lost communication scenarios are important for developing these skills. Many flight training programs now incorporate realistic lost comes drills that challenge pilots to apply FAR 91.185 procedures in complex scenarios. These exercises build confidence and competence that directly enhance real-world emergency performance. Consider requesting specific lost communication practice during your next IFR proficiency check or simulator session.
By analyzing incidents systematically and incorporating lessons into training programs, you can refine your decision-making and safety protocols, improving your preparation for unexpected communication breakdowns.