Which chemicals are permitted for use to remove frost and ice only by prior arrangement with ATP Maintenance Control?

The correct answer is glycol or alcohol because these substances are specifically approved for use in the aircraft industry for de-icing and anti-icing purposes. Glycol, often in the form of propylene or ethylene glycol, is commonly utilized as an effective de-icing solution due to its low freezing point and its ability to lower the freezing point of water when mixed. Alcohol can also be effective for this purpose, especially in solvents used for removing frost and preventing ice from forming on various surfaces.

The proper handling of these chemicals is critical, which is why their use requires prior coordination with ATP Maintenance Control. This ensures that the procedures align with safety standards and that the correct formulations are used to avoid any potential damage to the aircraft or its systems. Usage of these chemicals is managed to maintain compliance with legal and environmental regulations and to ensure that they are applied effectively and safely.

Other options, while they may have some de-icing properties or benefits in certain conditions, are not sanctioned for use in the aviation environment without specific oversight or arrangements.