(a) The cessation, temporary lifting, re-establishment, extension or other alteration of an aerial blockade must be declared and notified to all States.
(b) Whenever feasible, a Notice to Airmen (NOTAM) about any changes under paragraph (a) ought to be issued by the Blockading Party in accordance with Rule 55.
- This Rule is based on Art. 12 and on Art. 13 of the 1909 London Declaration and is self-explanatory. As to the content of the declaration and the manner of notification see the Commentary on Rule 148 (a) − (b). Again, if feasible, a NOTAM ought to be issued (see Commentary on Rule 148 (c)).
- The obligation under Rule 149 (a) does not apply in cases where, due to stress of weather, the Blockading force has been temporarily withdrawn. This especially holds true if the weather conditions as such prevent any aviation.
- If the Blockading force is withdrawn for any other reason, and the blockade is to be re-established, the same formalities must be observed as if it were established for the first time.
- The mere fact that military aircraft enforcing the aerial blockade are not in the air may not be considered a cessation or temporary lifting. The airspace may be monitored by long-range electronic surveillance (e.g. AWACS), which would enable the Blockading force to immediately respond to any attempt of breaching the aerial blockade. See also paragraph 3 of the Commentary on Rule 151, as well as Rule 154.
- Art. 12 of the London Declaration: “The rules as to declaration and notification of blockade apply to cases where the limits of a blockade are extended, or where a blockade is re-established after having been raised.”
- Art. 13 of the London Declaration: “The voluntary raising of a blockade, as also any restriction in the limits of a blockade, must be notified in the manner prescribed by Article 11.”
- Art. 4 of the London Declaration: “A blockade is not regarded as raised if the blockading force is temporarily withdrawn on account of stress of weather.”