SCHEDULE CHANGE. A planned change or a flight number/time change which can occur up to more than 72 hours prior to the flight's scheduled. departure. Examples - Change of flight times, change of flight numbers, reduction of service, discontinuation of all service. in a market. American uses an automated schedule change process up to 72 hours prior to departure. Through this automated. process all schedule changes are sent to the booking source for notification.
Describe the particles that make up the nucleus of an atom in terms of mass and charge. Protons, neutrons and electrons. Protons have a relative mass of 1 and a charge of +1, they are found in the nucleus of an atom.
The atomic mass number of an element is determined by mass of the nucleus of an atom. Therefore the particles that make up the nucleus determine the mass number. These particl â¦ es are protons and neutrons.  The mass of the protons and neutrons do not vary between elements, but the number of each in the nucleus varies between elements and between isotopes of the same element.