What restrictions are there on a flight in international airspace? For example, if you fly into the Pacific Ocean more than 12 miles (or whatever the distance is) offshore, are you free to fly any speed (such as faster than sound), at any altitude, or in any weather? Are FAA regulations in effect?
Is anybody really "in charge" of this airspace? If not, how do airliners keep organized on intercontinental flights?
When a US registered pilot is operating in international airspace, he is bound by both the US aviation regulations (14 CFR) and ICAO Annex 2, as required by 14 CFR 91.703. It also requires compliance with MNPS and RVSM airspace rules where appropriate.
Sec. 91.703 - Operations of civil aircraft of U.S. registry outside of the United States.
(a) Each person operating a civil aircraft of U.S. registry outside of the United States shall--
(1) When over the high seas, comply with annex 2 (Rules of the Air) to the Convention on International Civil Aviation and with Secs. 91.117(c), 91.127, 91.129, and 91.131;
(2) When within a foreign country, comply with the regulations relating to the flight and maneuver of aircraft there in force;
[(3) Except for Sec. Sec. 91.117(a), 91.307(b), 91.309, 91.323, and 91.711, comply with this part so far as it is not inconsistent with applicable regulations of the foreign country where the aircraft is operated or annex 2 of the Convention on International Civil Aviation; and]
(4) When operating within airspace designated as Minimum Navigation Performance Specifications (MNPS) airspace, comply with Sec. 91.705. When operating within airspace designated as Reduced Vertical Separation Minimum (RVSM) airspace, comply with Sec. 91.706.(b) Annex 2 to the Convention on International Civil Aviation, Ninth Edition--July 1990, with Amendments through Amendment 32 effective February 19, 1996, to which reference is made in this part, is incorporated into this part and made a part hereof as provided in 5 U.S.C. Sec. 552 and pursuant to 1 CFR part 51. Annex 2 (including a complete historic file of changes thereto) is available for public inspection at the Rules Docket, AGC-200, Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591; or at the Office of the Federal Register, 800 North Capitol Street, NW., Suite 700, Washington, DC. In addition, Annex 2 may be purchased from the International Civil Aviation Organization (Attention: Distribution Officer), P.O. Box 400, Succursale, Place de L'Aviation Internationale, 1000 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2R2.
Another unrelated FAA document explains it in plain language:
International Civil Aviation Organization (ICAO)
ICAO is an agency of the United Nations that originated from the signing of the Convention on International Civil Aviation in December 1944 (referred to as the Chicago Convention). This organization was formed to promote the safe and orderly development of international civil aviation. The Chicago Convention produced International Standards and Recommended Practices (SARP) aimed at standardizing international civil aviation operational practices and services. Currently, these SARP's are contained in 18 annexes to the Chicago Convention. In particular, Annex 2, Rules of the Air, and Annex 11, Air Traffic Services, are pertinent to this paper as they relate to civil aircraft operations, the establishment of airspace, and air traffic control (ATC) services in international airspace. Although not addressed in this paper, it should be noted that the SARP's are augmented by various ICAO documents containing Procedures for Air Navigation Services (PANS) that amplify the basic principles in the SARP's. Further, to supplement the worldwide procedures contained in the annexes and PANS, ICAO develops Regional Supplementary Procedures, which are part of the Air Navigation Plans agreed upon to meet the needs of specific geographical areas.
Two articles of the Chicago Convention also have a bearing on the subject of this paper:
Article 3:
Exempts state-owned aircraft (which includes military aircraft) from the provisions of Annex 11 and its Standards and Recommended Practices. (Note: As an ICAO Contracting State, the U.S. has agreed that its state aircraft will be operated in international airspace with due regard for the safety of civil aircraft.)
Article 12:
Obligates each ICAO Contracting State to adopt measures to insure that persons operating an aircraft within its territory shall comply with that state's air traffic rules; or with Annex 2, Rules of the Air, when operating over the high seas. The U.S. satisfied this responsibility through Title 14, Code of Federal Regulations (CFR) Part 91 which requires that operators of aircraft comply with U.S. operating rules when in the U.S., and that U.S.-registered aircraft comply with Annex 2 when over the high seas (see section 91.703). However, section 91.703 applies only to civil aircraft, and state aircraft operating outside the U.S. are only subject to the "due regard" provisions of Article 3 of the Convention.
Under ICAO agreements, the SARP's in Annex 11 apply to airspace under the jurisdiction of a contracting state which has accepted the responsibility of providing air traffic services over the high seas, or in airspace of undetermined sovereignty.
The relevant FAA information is available here. As the page says:
The dynamics of oceanic and remote international operations are such that they are constantly evolving and it is incumbent upon the operators to closely monitor any changes
The general approach as I very roughly understand it is that ICAO defines general procedures, airspace etc. for international airspace but each country is responsible for ensuring that their aircraft comply, so if - for example - you want to cross the North Atlantic in an N-registered aircraft then you require FAA approval.
The North Atlantic Operations and Airspace Manual says:
Within this airspace a formal Approval Process by the State of Registry of the aircraft or the State of the Operator ensures that aircraft meet defined MNPS Standards and that appropriate crew procedures and training have been adopted.
The document does acknowledge that it's mainly aimed at airlines but it also states that it applies to GA flights too:
Aircraft without NAT MNPS or RVSM Approvals may, of course, also fly across the North Atlantic below FL285. However, due consideration must be given to the particular operating environment. Especially by pilots/operators of single and twin engine aircraft. Weather conditions can be harsh; there are limited VHF radio communications and ground-based navigation aids; and the terrain can be rugged and sparsely populated. International General Aviation (IGA) flights at these lower levels constitute a very small percentage of the overall NAT traffic but they account for the vast majority of Search and Rescue operations. Specific guidance for the pilots and operators of such flights was previously contained in the North Atlantic International General Aviation (NAT IGA) Operations Manual published by the FAA on behalf of the ICAO North Atlantic Systems Planning Group (NAT SPG). However, with effect from this Edition 2013, such guidance has been subsumed into this document.
