Task VII.A
Loss of Communications
To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with loss of communications while operating solely by reference to instruments.
References: 14 CFR part 91; AIM; FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-15, FAA-H-8083-16, FAA-H-8083-25
Quick Review
Conversational Q&A — quiz yourself before the oral.
- Try the last assigned frequency again, then the previously assigned frequency
- Try any other known frequencies for the facility — preferably the next sector's — and try calling an FSS
- Monitor your NAVAIDs — ATC may transmit instructions over a VOR, VORTAC, NDB, or localizer voice channel
- If only your transmitter failed, listen for ATC instructions on any operational receiver, including the nav radios
- Squawk 7600 and keep trying to re-establish contact (IFH ch. 11; IPH ch. 2)
Your data block on the controller's scope flashes RDOF (radio failure), alerting the controller that you have a two-way radio communications failure (IPH ch. 2). ATC then knows to apply lost-comm expectations to your target while you continue trying to re-establish contact.
Continue the flight under VFR and land as soon as practicable (91.185(b)). This rule applies whether the failure occurs in VFR conditions or you encounter them afterward — it takes priority over the IFR route/altitude procedures.
"Practicable" is not "as soon as possible" — you keep the prerogative of judgment and are not required to land at an unauthorized or unsuitable airport (IPH ch. 2).
7,000 — the highest of the assigned altitude (5,000), the minimum IFR altitude (6,000), and the expected altitude (7,000) for the route segment being flown (91.185(c)(2)). Re-evaluate at every segment: the answer can change as the MEA changes.
- Begin the climb to the higher MEA when you reach the fix where the MEA rises
- If that fix has a published MCA, start the climb early enough to cross the fix at or above the MCA
- When a later segment's MEA drops back below your assigned/expected altitude, descend at the fix where the MEA decreases, down to the last assigned altitude or the altitude ATC advised to expect (IPH ch. 2)
Commence descent, or descent and approach, as close as possible to the expect-further-clearance (EFC) time if you received one. If you did not, begin as close as possible to your ETA as calculated from the filed — or amended with ATC — estimated time en route (91.185(c)(3)(i)).
- Leave the clearance limit at the EFC time if one was received
- If none was received, leave it upon arrival over it
- Then proceed to a fix from which an approach begins and commence descent, or descent and approach, as close as possible to the ETA from your filed or amended ETE (91.185(c)(3)(ii))
- Your airplane: a failed transmitter, receiver, or both — and an electrical charging-system failure, which gives you roughly 30–40 minutes of battery before everything electrical quits (IFH ch. 11)
- The ground: an ARTCC radio frequency outage — the backup transmitter is usually in service within 60 seconds, so wait at least one minute before concluding the frequency has actually failed (IPH ch. 2)
Because complete failures are rare, troubleshoot before you assume — a partial failure (transmitter only) still lets you receive instructions (IPH ch. 2).
- The 91.185 procedures apply "unless otherwise authorized by ATC" (91.185(a))
- If you're in — or encounter — VFR conditions, you must continue under VFR and land as soon as practicable (91.185(b))
- And as PIC you retain emergency authority to deviate from any rule to the extent required to meet the emergency (91.3)
The regulation's purpose is to keep you predictable — extended no-radio IFR operation adversely affects other users of the airspace (IPH ch. 2).
Deep Dive
The clearance-limit clock
The route and altitude rules are mechanical; the timing rule is where applicants stumble. The system's logic: ATC can still separate traffic around a silent airplane as long as that airplane does exactly what was assigned, expected, or filed — and shows up at the destination when its ETE said it would (IPH ch. 2).
No — commence the descent and approach as close as possible to your ETA as calculated from the filed or amended ETE (91.185(c)(3)(i)). Hold at the fix until then. ATC is protecting the approach environment based on when the system expects you, not when you happen to show up.
Re-establishing contact — the ARTCC outage playbook
Losing the Center frequency doesn't always mean your radios died. The recommended sequence when a frequency change goes unanswered (IPH ch. 2):
- Wait at least one minute — backup transmitter switchover seldom takes more than 60 seconds (IPH ch. 2)
- If you can't raise the new sector, re-contact the transferring controller for an alternate frequency or instructions
- If the failure happens after contact was established, try any other known ARTCC frequency — preferably the next sector's — and ask for instructions
- Failing that, request communication instructions from the FSS appropriate to your route — FSS relay is faster than company radio because FSS has direct interphone lines to the responsible ARTCC sector (IPH ch. 2)
The electrical angle
Once the charging system fails you have roughly 30–40 minutes of battery, and possibly less — never continue the flight once the charging system has failed; land at the nearest suitable airport (IFH ch. 11).
- Load-shed: turn off or pull breakers on all non-essential electrical equipment
- Tell ATC now, while you still can — advise them of the situation and the impending electrical failure (IFH ch. 11)
- Plan for the panel you'll have left; in a glass cockpit this failure also takes your displays (covered under Task VII.D)
Risk: sticking to the procedure (IR.VII.A.R2)
Separation in IMC depends on ATC predicting your path. The primary objective of the lost-comm rules is to preclude extended IFR no-radio operations, because a silent, unpredictable airplane adversely affects every other user of the airspace (IPH ch. 2). Fly AVEF and the highest-of-three altitude, arrive on your ETA, and the system can work around you. The sanctioned "improvisations" are exactly three: ATC authorization, VFR conditions, or a genuine emergency (91.185, 91.3).
Official ACS elementsreference
Knowledge1 element
The applicant demonstrates understanding of:
IR.VII.A.K1Procedures to follow in the event of lost communication during various phases of flight, including techniques for reestablishing communications, when it is acceptable to deviate from an instrument flight rules (IFR) clearance, and when to begin an approach at the destination.
Risk Management2 elements
The applicant is able to identify, assess, and mitigate risk associated with:
IR.VII.A.R1Possible reasons for loss of communication.IR.VII.A.R2Deviation from procedures for lost communications.
Skills5 elements
The applicant exhibits the skill to:
IR.VII.A.S1Recognize a simulated loss of communication.IR.VII.A.S2Simulate actions to re-establish communication.IR.VII.A.S3Determine whether to continue to flight plan destination or deviate.IR.VII.A.S4Determine appropriate time to begin an approach.IR.VII.A.S5Use single-pilot resource management (SRM) or crew resource management (CRM), as appropriate.