An expiration date for replacing (or recharging) the battery  must be legibly marked on the outside of the transmitter  and entered in the aircraft maintenance record. This does  not apply to batteries that are essentially unaffected during  storage intervals, such as water-activated batteries.  The preflight inspection is a thorough and systematic means  by which a pilot determines if an aircraft is airworthy and in  condition for safe operation. POHs and owner/information  manuals contain a section devoted to a systematic method  of performing a preflight inspection.  The annual and 100-hour inspection requirements do not  apply to large (over 12,500 pounds) airplanes, turbojets, or  turbopropeller-powered multi-engine airplanes or to aircraft  for which the owner complies with a progressive inspection  program. Details of these requirements may be determined  by referencing 14 CFR, part 43, section 43.11 and 14 CFR  part 91, subpart E, or by inquiring at a local FSDO.  hours for the purpose of traveling to a location at which the  required inspection can be performed. Any excess time used  for this purpose must be included in computing the next 100  hours of time in service.  Under 14 CFR, part 91, section 91.411, requires that the  altimeter, encoding altimeter, and related system must be  tested and inspected within the 24 months prior to operating in  controlled airspace under instrument flight rules (IFR). This  applies to all aircraft being operated in controlled airspace.  Under 14 CFR, all aircraft instruments and installed equipment  are required to be operative prior to each departure. When the  FAA adopted the minimum equipment list (MEL) concept for  14 CFR part 91 operations, it allowed aircraft to be operated  with inoperative equipment determined to be nonessential for  safe flight. At the same time, it allowed part 91 operators,  without an MEL, to defer repairs on nonessential equipment  within the guidelines of part 91.  The FAA has two acceptable methods of deferring  maintenance on small rotorcraft, non-turbine powered  airplanes, gliders, or lighter-than-air aircraft operated under  part 91. They are the deferral provision of 14 CFR, part 91,  section 91.213(d) and an FAA-approved MEL.  Title 14 CFR, part 91, section 91.413, requires that before  a transponder can be used under 14 CFR, part 91, section  91.215(a), it shall be tested and inspected within the 24  months prior to operation of the aircraft regardless of airspace  restrictions.  An emergency locator transmitter (ELT) is required by 14  CFR, part 91, section 91.207, and must be inspected within  12 calendar months after the last inspection for the following:  The deferral provision of 14 CFR, part 91, section 91.213(d)  is widely used by most pilot/operators. Its popularity is due  to simplicity and minimal paperwork. When inoperative  equipment is found during a preflight inspection or prior to  departure, the decision should be to cancel the flight, obtain  maintenance prior to flight, or to defer the item or equipment.  Maintenance deferrals are not used for inflight discrepancies.  The manufacturer’s AFM/POH procedures are to be used in  those situations. The discussion that follows assumes that  the pilot wishes to defer maintenance that would ordinarily  be required prior to flight.  The ELT must be attached to the airplane in such a manner  that the probability of damage to the transmitter in the event  of crash impact is minimized. Fixed and deployable automatic  type transmitters must be attached to the airplane as far aft  as practicable. Batteries used in the ELTs must be replaced  (or recharged, if the batteries are rechargeable):  Using the deferral provision of 14 CFR, part 91, section  91.213(d), the pilot determines whether the inoperative  equipment is required by type design, 14 CFR, or ADs. If  the inoperative item is not required, and the aircraft can be  safely operated without it, the deferral may be made. The  inoperative item shall be deactivated or removed and an  INOPERATIVE placard placed near the appropriate switch,  control, or indicator. If deactivation or removal involves  Minimum Equipment Lists (MEL) and  Operations With Inoperative Equipment  Altimeter System Inspection  Transponder Inspection  Emergency Locator Transmitter  Other Inspection Programs  Preflight Inspections  • When the transmitter has been in use for more than 1  cumulative hour  • When 50 percent of the battery useful life or, for  rechargeable batteries, 50 percent of useful life of the  charge has expired  • The presence of a sufficient signal radiated from its  antenna  • Operation of the controls and crash sensor  • Battery corrosion  • Proper installation  9-9 