Airworthiness Directive · Amendment 39-14380 · British Aerospace Model HS 748 Airplanes
British Aerospace Model HS 748 Airplanes
This AD applies to all BAE Systems (Operations) Limited Model HS 748 series 2A and series 2B airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all British Aerospace Model HS 748 airplanes. This AD requires repetitive inspections for fatigue cracking, corrosion, and other related discrepancies of the rear pressure bulkhead and associated areas, and the fin attachment fittings, particularly the fin link beam; and related investigative and corrective actions. This AD results from a structural integrity audit of the airplane that showed the importance of inspecting for fatigue cracking and corrosion of these areas. We are issuing this AD to detect and correct cracking, corrosion, and other related discrepancies of the rear pressure bulkhead and associated areas, and the fin attachment fittings, particularly the fin link beam, which could result in damage to the airplane structure or injury to airplane occupants.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
At the applicable time in paragraph (f)(1), (f)(2), or (f)(3) of this AD: Do high frequency eddy current (HFEC), rototest eddy current, radiographic, and detailed inspections for fatigue cracking, corrosion, and other related discrepancies of the rear pressure bulkhead and associated areas, and the fin attachment fittings, particularly the fin link beam; and do applicable related investigative and corrective actions before further flight except as provided by paragraph (g) of this AD. Do all actions in accordance with the Accomplishment Instructions of BAE Systems (Operations) Limited Inspection Service Bulletin HS748-53-49, Revision 2, dated May 4, 2001.
(1) For airplanes with maximum cabin differential pressure of 5.5 psi, do the inspections at the applicable time in paragraphs (f)(1)(i) and (f)(1)(ii) of this AD.
(i) Before the accumulation of 50,000 total flight cycles, or within 6 months after the effective date of this AD, whichever occurs later.
(ii) Before the accumulation of 83,000 total flight cycles, or within 6 months after the effective date of this AD, whichever occurs later: Extend the inspection of the fin link beam to cover the central 30 inches of the beam, and repeat this inspection at intervals not to exceed 11,000 flight cycles. If the inspection of the fin link beam indicates a defect in any rivet hole, before further flight: Repair the hole in accordance with the service bulletin, and repeat the inspection thereafter at intervals not to exceed the applicable interval in Table 1 of this AD, depending on the size of the hole following reaming during the repair process.
| Defect removed at— | Repetitive inspection interval |
|---|---|
| Hole size 3/16 inch + 1/32 inch diameter | 10,000 flight cycles. |
| Hole size 3/16 inch + 1/16 inch diameter | 7,000 flight cycles. |
| Hole size 3/16 inch + 5/64 inch diameter | 6,000 flight cycles. |
(2) For airplanes on which BAe Modification 7191 has been incorporated (reduction of cabin differential pressure from 5.5 psi to 4.2 psi) before the effective date of this AD: Do the inspections at the applicable time in paragraphs (f)(2)(i), (f)(2)(ii), and (f)(2)(iii) of this AD.
(i) If Modification 7191 is incorporated before the accumulation of 50,000 total flight cycles, do the inspections before the accumulation of 50,000 total flight cycles, or within 6 months after the effective date of this AD, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 25,000 flight cycles.
(ii) If Modification 7191 is incorporated during one of the inspections required by this AD: Repeat the inspection thereafter at intervals not to exceed 25,000 flight cycles.
(iii) If Modification 7191 is incorporated between inspections required by this AD: Do the inspection 11,000 flight cycles following the previous inspection, and repeat the inspection thereafter at intervals not to exceed 25,000 flight cycles. If the inspection of the fin link beam indicates a defect in any rivet hole, before further flight: Repair the hole in accordance with the service bulletin, and repeat the inspection thereafter at intervals not to exceed the applicable interval in Table 2 of this AD, depending on the size of the hole following reaming during the repair process.
| Defect removed at— | Repetitive inspection interval |
|---|---|
| Hole size 3/16 inch + 1/32 inch diameter | 22,000 flight cycles. |
| Hole size 3/16 inch + 1/16 inch diameter | 16,000 flight cycles. |
| Hole size 3/16 inch + 5/64 inch diameter | 14,000 flight cycles. |
(3) For series 1 airplanes, including Model 200, Constructors Number 1535 (maximum cabin differential pressure of 4.2 psi): Before the accumulation of 70,000 total flight cycles, or within 6 months after the effective date of this AD, whichever occurs later. If the inspection of the fin link beam indicates a defect in any rivet hole, before further flight: Repair the hole in accordance with the service bulletin, and repeat the inspection thereafter at intervals not to exceed the applicable interval in Table 2 of this AD, depending on the size of the hole following reaming during the repair process.
Note 1: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”
(g) Where BAE Systems (Operations) Limited Inspection Service Bulletin HS748-53-49, Revision 2, dated May 4, 2001, recommends contacting BAE Systems (Operations) Limited for appropriate action: Before further flight, do the action according to a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA. Where the service bulletin is not specific regarding an inspection, corrective action, or any step necessary to complete the requirements of this AD: Before further flight, do the inspection, corrective action, or step according to a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, or by the CAA (or its delegated agent).
Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.
