Are pilots legally required to verbally declare an emergency to invoke §91.3(b)'s deviation authorization?

Question

Related:Do you have to explain what your emergency is?

I am aware that pilots are required to declare an emergency and inform ATC of as much information as possible during IFR flight due to this rule:

§91.183 IFR communications.

Unless otherwise authorized by ATC, the pilot in command of each aircraft operated under IFR in controlled airspace must ensure that a continuous watch is maintained on the appropriate frequency and must report the following as soon as possible—

(a) The time and altitude of passing each designated reporting point, or the reporting points specified by ATC, except that while the aircraft is under radar control, only the passing of those reporting points specifically requested by ATC need be reported;

(b) Any unforecast weather conditions encountered; and

(c) Any other information relating to the safety of flight.

Is there any rule that requires the declaration of a VFR emergency for it to be legally valid for the purpose of rule deviation?

My assumption is no because a 2-way radio is not even required in all locations.

Answer 1

The short answer is no, there is no specific requirement for VFR flights to state an emergency, however you may be expected to explain yourself and your actions once you reach the ground.

My assumption is no because a 2-way radio is not even required in all locations.

To expand on this you don't need a radio on board for VFR flight (FAA FAR 91.205) so they would have a legally contradicting issue if they required you to announce when you don't have a radio. As mentioned by Ron in the question you linked the rule is "Aviate, Navigate, Communicate" If you are too busy with the first two that is far more important.

Im not sure where they are pulling the quotes but this NASA presentation on emergencies sums it up well.

“…an intent of 91.3 is to ensure the PIC will handle the emergency in a manner necessary to save lives and not be worried about regulatory compliance.”

“I’ve never seen a pilot violated for deviating from a regulation when that pilot has either declared an emergency OR has stipulated in ANY written response to the FAA that an emergency existed at the time of the deviation.”

This article has some interesting points from a lawyers perspective on the situation,

Madsen defended a case for a pilot who deviated from an assigned altitude due to extreme turbulence while flying a Cessna 150. The pilot had dropped his handheld mic, so he couldn't initially communicate his situation. He stabilized the airplane and was about 600 feet off his altitude when ATC called him. At that point he was able to find the mic and he told the controller what had happened. "It's unrealistic in some situations to communicate your emergency before you secure the aircraft," Madsen said. "You want to control the aircraft first." Madsen said the case was ultimately dismissed, but he felt it would have been much easier to defend had the pilot declared his emergency.

Here we can see that ultimately the pilot was in the right and while he should have declared, there was no legal grounds that required it.

On some level you are at the mercy of the FAA with this one and its clearly a case by case basis (as is everything in aviation) and the lawyer in the above article goes on to say

Some FAA field offices take the wording very seriously. Such was the case with the Cessna 150 pilot who deviated from his altitude. "They questioned why he didn't state an emergency and call out mayday, and they took great issue with the fact that he didn't use the accepted terms," Madsen said.

Again the case was ultimately dismissed whether or not they were happy about that.

Answer 2

First of all, FAA regulations are not laws, they are regulations. Federal laws are made by members of Congress elected by the people of the several states. Regulations are issued by executive-appointed bureaucrats. The word "legal" or "legally" is properly used when speaking of laws, not regulations. Violations of regulations are usually what are called "civil violations," and have nothing to do with "illegality" which normally refers to criminal actions.

When Washington bureaucrats discuss regulations they do not use the words "legal" or "illegal" for the reasons stated above. They use terms such as "compliant" or "non-compliance". Non-compliance with an FAA regulation has nothing to with "legality". I know there are a lot of people who fantasize about controlling every time a pilot wipes their butt and throwing them in jail for any imagined act of willfulness, but so far that has not happened, so please do not refer to FAA regulations as though they were laws.

As for your question, pilots are required to declare an emergency only if the circumstances permit it.

A pilot can deviate from ATC instructions any time they determine that it is required for safety. Notifying ATC of a deviation is purely secondary to the primary goal of preserving the aircraft and avoiding crashing.

If a pilot deviates from an instruction in a way that is of concern to ATC, then an explanation can be demanded by certain appropriate officials at the discretion of those officials. If they find the pilot's explanation unsatisfactory or indicative of poor judgement, they can revoke the pilot's license.