Airworthiness Directive · Amendment 39-11586 · Fokker Model F.28 Mark 0070 and 0100 Series Airplanes
Fokker Model F.28 Mark 0070 and 0100 Series Airplanes
All Model F.28 Mark 0070 and 0100 series airplanes, certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to all Fokker Model F.28 Mark 0070 and 0100 series airplanes, that requires a measurement of the resistance of the electrical connectors of the auxiliary power unit (APU) to detect a short circuit; an inspection to determine if the grommets or shrink sleeves are present; and modification, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to detect and prevent a short circuit of a fire extinguisher electrical system due to a lack of shrink sleeves or grommets, and consequent disabling of the affected fire extinguisher system.
To detect and prevent a short circuit of a fire extinguisher electrical system due to a lack of shrink sleeves or grommets, and consequent disabling of the affected fire extinguisher system, accomplish the following:
(a) Within 12 months after the effective date of this AD, perform a measurement of the resistance of the electrical lines on the auxiliary power unit (APU) and engine fire extinguisher bottles to detect a short circuit, in accordance with Part A of the Accomplishment Instructions of Fokker Service Bulletin SBF100-26-015, dated August 15, 1999.
(1) If no short circuit is detected, at the next scheduled weight check of the fire extinguishing bottle, or within 2 years after the inspection required by paragraph (a) of this AD, whichever occurs first, perform a general visual inspection to determine if the grommets or shrink sleeves are present and installed properly. If any grommet or shrink sleeve is missing or not installed properly, prior to further flight, perform the modification of the connectors, in accordance with Part B of the Accomplishment Instructions of the service bulletin.
(2) If any short circuit is detected, prior to further flight, perform a general visual inspection to determine if the grommets or shrink sleeves are present and installed properly. If any grommet or shrink sleeve is missing or not installed properly, prior to further flight, perform the modification of the connectors, in accordance with Part B of the Accomplishment Instructions of the service bulletin.
Note 2: For the purposes of this AD, a general visual inspection is defined as “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
