PS Form 3883 is used for filing a Postal Report of Accident, Injury, or Occupational Disease. The penalty for late filing of this form is not explicitly mentioned in the postal regulations or guidelines. However, it is generally recommended to file the form as soon as possible after the incident occurs. Failing to report an accident or injury promptly could potentially affect the investigation of the incident and could be viewed negatively by postal authorities. Therefore, it is important to file the form as soon as you become aware of the incident to ensure a timely and accurate process.