What action is required if an error is found in a Form D after "Time Effective" has been issued?

If an error is discovered in a Form D after the "Time Effective" has been issued, the appropriate action is to cancel the Form D. This is crucial because once the Form D is in effect, it governs the operations and provides critical instructions to train crews. An error could lead to safety risks, operational confusion, or potential accidents. Canceling the Form D ensures that the erroneous information is not acted upon and allows for a proper assessment and correction of the situation before reissuing a new and accurate Form D.

While revising and reissuing the form may seem viable, it cannot be done while the original is still effective, as this could cause confusion regarding which instructions to follow. Recording an error or merely informing the crew without taking action could permit unsafe situations to develop, as the crew might operate based on incorrect information. Therefore, the emphasis is on ensuring safety by canceling the erroneous Form D before any further actions are taken.