Bob is a certificated ASEL private pilot. He steals Jane's Cessna 172 and flies it. He buys the fuel for the flight at his own expense, and after the flight, he pays Jane a reasonable rental rate. (In other words, he is not getting flight hours for any less money than he could by legal means, so there's no possible compensation issue.) The flight would have been completely legal if he had had Jane's permission. Is he considered the pilot in command while flying the stolen plane for the purpose of logging flight time?
The information below represents my opinion:
NOTE: This question has been edited since my (original) answer was posted. The OP added the following words to the end of his last sentence: "...for the purpose of logging flight time?" I have modified my answer to more clearly respond to his edit/qualifier regarding the "logging" of flight time.
If he is the sole occupant he would be "operating" the airplane and the definition of "Operate" according to 14 CFR Part 1.1 is:
with respect to aircraft, means use, cause to use or authorize to use aircraft, for the purpose (except as provided in § 91.13 of this chapter) of air navigation including the piloting of aircraft, with or without the right of legal control (as owner, lessee, or otherwise).
Also, according to 14 CFR 61.51(e)(1)(i) and (ii) he can, but is not required to, log the time as "Pilot in Command."
. . . (pertinent sections)
(e) Logging pilot-in-command flight time.
(1) A sport, recreational, private, commercial, or airline transport pilot may log pilot in command flight time for flights-
(i) Except when logging flight time under § 61.159(c), when the pilot is the sole manipulator of the controls of an aircraft for which the pilot is rated, or has sport pilot privileges for that category and class of aircraft, if the aircraft class rating is appropriate;
(ii) When the pilot is the sole occupant in the aircraft;
The logging of pilot-in-command time, as written in 14 CFR Part 61.51, does not have a qualifier with respect to whether or not the time was acquired in an aircraft that was stolen. And, to be more precise, the FAA only mandates, with respect to FAR Part 61, the logging/documenting of the flight/ground time to demonstrate that the necessary training, aeronautical experience and recent experience requirements of FAR Part 61 have been met. (see 14 CFR Part 61.51(a)(1)and (2))
Your logbook or other document/record where your flight/ground time is recorded belongs to you. A person may enter anything they want in their own records. However, when you present time from your logbook or other document for the purpose of demonstrating you meet any FAR Part 61 experience/training requirement that specific time must have been recorded as prescribed in FAR Part 61.51.
Finally, according to 14 CFR Part 1.1 (linked above) -
Pilot in command means the person who:
(1) Has final authority and responsibility for the operation and safety of the flight;
(2) Has been designated as pilot in command before or during the flight; and
(3) Holds the appropriate category, class, and type rating, if appropriate, for the conduct of the flight.
So, since he "has the final authority and responsibility for the operation and safety of the flight" as the "sole occupant" of the aircraft, in my opinion he would be considered "pilot in command."
Also, item number 2 above requires that he be "designated" as the pilot in command. It does not specify how this "designation" is made or who has the authority to make this "designation." Remember that a person is considered to "operate" an aircraft with or without the right of legal control (see the definition of "operate" noted above).
(all emphasized items are mine)
A few thoughts:
I think this question ("Is he considered the pilot in command while flying the stolen plane?) would be contingent upon who, or what agency/organization, would be doing the "considering" and for what purpose would the "considering" be at issue.
In view of the circumstances specified in your question, who else could possibly be considered, under a casual or strict interpretation, the "pilot in command," other than the person flying the airplane as the sole occupant?
This question may be better suited for the S.E. - Legal.
The FAA doesn't have the authority to decide if you had stolen the aircraft you've been flying. Only a criminal court can determine that. The FAA may then act on the court's decision.
The FAA may issue licenses to convicted felons, unless the conviction was for addiction-related offenses. However, the FAA does require that ATP applicants be of good moral character. There's been a relevant question - What does the FAA consider to be "good moral character"? - and felonies trigger an inquiry.
There is no separate FAA-imposed penalty such as not logging the time spent committing a crime - the regulations do not address that. Generally FAA rules suggest logging the time, even if some regulations were violated. The one requirement that matters is that the pilot is in control, including having the required skills.
Realistically, since pilots fill their logbooks themselves, it would be up to the pilot's conscience to log or not log the time. It would usually not be obvious to anyone reading the logbook whether the aircraft was operated with the owner's permission. For FAA purposes, that is not important per se.
14 CFR §61.51(e) covers logging PIC time.
It does not include legal ownership of the aircraft or a valid rental contract as one of the prerequisite conditions, therefore a thief may log PIC time provided they meet all other provisions of this section.