{"id":"F2008L03774","name":"AD/BD-700/1 - Elevator PCU Attachment Bolts","slug":"ad-bd-700-1-elevator-pcu-attachment-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":75523,"registerId":"commonwealth-F2008L03774-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier BD-700 Series Aeroplanes","sectionType":"division","heading":"Bombardier BD-700 Series Aeroplanes","content":"### Bombardier BD-700 Series Aeroplanes\n\n| AD/BD-700/1 | Elevator PCU Attachment Bolts | 12/2008 TX |\n| ----------- | ----------------------------- | ---------- |\n\n| Applicability: | Bombardier Aerospace BD-700-1A10 and BD-700-1A11 aeroplanes, serial numbers (S/N) 9002 through 9222, equipped with elevator PCUs part number (P/N) GT411-3800-5 or GT411-3800-7. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. For all elevator PCU P/N GT411-3800-5 and for elevator PCU P/N GT411-3800-7, S/N 0615 and lower, excluding S/N listed in Table 1 below, which have accumulated 1000 hours air time or more as of the effective date of this AD accomplish the following:a. Inspect and lubricate the PCU attachment joints in accordance with Service Bulletin (SB) A700-1A11-27-024 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, or SB A700-27-066 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, as applicable.b. Repeat an inspection and lubrication of the PCU attachment joints in accordance with SB A700-1A11-27-024 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, or SB A700-27-066 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, as applicable.c. Repeat an inspection of the PCU attachment joints and lubrication in accordance with SB A700-1A11-27-024 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, or SB A700-27-066 basic issue dated 2 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, as applicable.d. Complete a disassembly with inspection and lubrication of the PCU attachment joint components in accordance with SB 700-1A11-27-025 basic issue dated 9 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, or SB 700-27-067 basic issue dated 9 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, as applicable.e. If any damage or seizure was found following the above mention inspections, contact Bombardier Aerospace for disposition. |\n\n```html\n

SB 700-1A11-27-025 or 700-27-067 may be accomplished in lieu of Requirements 1a, 1b and 1c of this AD.

The Units listed below have been lubricated by the vendor and are not required to accomplish the instructions detailed in Requirements 1a, 1b and 1c of this AD.

Table 1:

P/N GT411-3800-7 units sent to vendor for maintenance have been returned as greased bearings

0030

0092

0141

0179

0206

0296

0427

0506

0031

0097

0145

0181

0208

0301

0429

0513

0033

0101

0156

0183

0210

0310

0430

0533

0041

0105

0161

0188

0214

0323

0431

0536

0046

0108

0163

0190

0218

0365

0433

0586

0060

0109

0164

0191

0222

0369

0435

0062

0110

0165

0197

0223

0406

0438

0066

0111

0171

0198

0240

0407

0453

0081

0119

0173

0199

0262

0408

0491

0083

0130

0174

0202

0265

0413

0495

0087

0138

0178

0205

0281

0420

0504

Note 1: Units listed in the above table must comply with Requirement 2.

2. For all other elevator PCU P/N GT411-3800-7 that are not covered in Requirement 1 of this AD, complete a disassembly with inspection and lubrication of the PCU attachment joint components in accordance with SB 700 1A11 27 025 basic issue dated 9 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, or SB 700-27-067 basic issue dated 9 October 2008 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, as applicable.

3. Report all findings to Bombardier Aerospace as defined in the applicable SB.

Terminating Action

Incorporation of Bombardier SB 700-1A11-27-025 or 700-27-067 constitutes terminating action for this AD.

Note 2: Transport Canada Urgent AD CF-2008-31 dated 9 October 2008 refers.

Compliance:

For Requirement 1a - Within 10 flight cycles or 50 flight hours, whichever comes first after the effective date of this AD.

For Requirement 1b - Within 90 days or 200 flight hours, whichever comes first, following the successful completion of Requirement 1a.

For Requirement 1c - Within 45 days or 100 hours air time, whichever comes first, following the successful completion of Requirement 1b.

For Requirement 1d - Within 45 days or 100 hours air time, whichever comes first, following the successful completion of Requirement 1c.

For Requirement 1e - Prior to further flight after the effective date of this AD.

For Requirement 2 - Within 180 days or 400 flight hours after the effective date of this directive, whichever comes first.

For Requirement 3 - Within 14 days after completion of each inspection detailed in Requirements 1 and 2 of this AD.

This Airworthiness Directive becomes effective on 13 October 2008.

Background:

During scheduled maintenance inspection, a bolt which connects the PCU to the elevator surface was found fractured in the assembly. Further inspection of the assembly revealed that the bearing on the PCU rod end had seized which resulted in damage to the attachment fitting bushing and fracture of the bolt. Inspection of other in-service airplanes revealed two more seized PCU attachment joints. However, except seizure, no fractured bolt was found on these airplanes. Failure of the bolts in both PCUs on one side could result in disconnection of the elevator control surface which would lead to flutter and loss of the aircraft.

\n```\n\n![](image.001.png) \nCharles Lenarcic \nDelegate of the Civil Aviation Safety Authority\n\n10 October 2008","sortOrder":0},{"sectionNumber":"AD/BD-700/1","sectionType":"part","heading":"AD/BD-700/1","content":"## AD/BD-700/1","sortOrder":1},{"sectionNumber":"Elevator PCU Attachment Bolts","sectionType":"part","heading":"Elevator PCU Attachment Bolts","content":"## Elevator PCU Attachment Bolts","sortOrder":2},{"sectionNumber":"12/2008 TX","sectionType":"part","heading":"12/2008 TX","content":"## 12/2008 TX","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused scope. It addresses a specific mechanical defect in a defined aircraft fleet and does not represent scope creep from original intent. The detailed applicability criteria and multiple compliance paths are typical for aviation safety instruments where precision is critical to avoid grounding aircraft unnecessarily while ensuring safety."},"complexity_factors":["Multiple nested applicability criteria (aircraft serial number ranges, specific part numbers, serial number thresholds for parts, and specific exclusions listed in Table 1)","Five distinct requirements (1a through 1e) with sequential dependencies and alternative compliance paths","Complex cross-referencing to four different Service Bulletins (SB A700-1A11-27-024, SB A700-27-066, SB 700-1A11-27-025, SB 700-27-067) with specific issue dates and approval authorities","Multiple compliance timeframes calculated from different baseline dates (effective date of AD vs completion of previous requirements)","Table of 63 specific serial numbers that create exceptions to general rules","Conditional logic where one action (SB 700-1A11-27-025 or 700-27-067) can substitute for three other requirements","Dual regulatory approval pathways (Chief, Continuing Airworthiness vs Chief, Continuing Airworthiness, Transport Canada)"],"plain_english_summary":"Owners and operators of Bombardier BD-700-1A10/1A11 jets (S/N 9002–9222) with elevator PCUs P/N GT411-3800-5 or -7 must inspect, lubricate, disassemble and inspect, report, and repair/replace seized or damaged PCU attachment hardware. A bolt fracture discovered in service can lead to loss of elevator pitch control and catastrophic failure, so affected aircraft must be inspected on a short schedule and grounded until defects are corrected."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The AD stays within the original safety-focused scope: it addresses seized bearings and fractured bolts at the elevator PCU attachment that could lead to elevator disconnection and loss of the aircraft. The actions required (inspect, lubricate, disassemble/inspect, report) are directly tied to that failure mode. The inclusion of a table of vendor-treated serial numbers and acceptance of service-bulletin completion as terminating action are implementation details rather than an expansion of purpose; they do not materially broaden the AD beyond the original intent to detect and remedy seized/damaged PCU attachment joints."},"complexity_factors":["Multiple conditional groups (Requirement 1 applies only to certain P/N and S/N ranges; Requirement 2 applies to the rest)","Several sequential actions with staggered deadlines (1a → 1b → 1c → 1d → 1e) with different time/flight-hour triggers","Cross-reference to multiple Bombardier service bulletins (SB A700-1A11-27-024, A700-27-066, SB 700-1A11-27-025, 700-27-067) and acceptance of later revisions only if regulator-approved","Table 1 listing dozens of specific unit serial numbers creating exceptions to the short-interval inspection requirements","Terminating action clause (SB disassembly/inspection constitutes termination) that interacts with the repeating inspection schedule","Reporting requirement (findings to Bombardier within 14 days) adding administrative compliance","References to approval by different authorities (Chief, Continuing Airworthiness; Transport Canada) introducing multi-jurisdictional approval paths","Multiple alternative compliance pathways (perform SB disassembly in lieu of repeated inspections) increasing decision branching","Different compliance windows expressed as either flight cycles or flight hours (whichever comes first) across different requirements","Technical specificity about part numbers, serial numbers and failure modes requiring maintenance-level interpretation"],"plain_english_summary":"**What this instrument requires (mechanical change)\n\n- Applies to Bombardier BD-700-1A10 and BD-700-1A11 aeroplanes, serial numbers 9002–9222, that are fitted with elevator PCUs (power control units) part numbers GT411-3800-5 or GT411-3800-7. (See \"Applicability\".)\n\n- For GT411-3800-5 units and for GT411-3800-7 units with serial number 0615 or lower (except those listed in Table 1), if the unit has 1,000 or more hours air time as of the AD effective date, operators must: 1) inspect and lubricate the PCU attachment joints using the Bombardier service bulletin (SB) procedures cited; 2) repeat that inspection/lubrication on the deadlines stated in the AD; and 3) carry out a disassembly, inspect and lubricate the attachment joint components per the disassembly SB. If damage or seizure is found, Bombardier must be contacted for disposition. (Requirement 1, subparagraphs a–e.)\n\n- For GT411-3800-7 units not covered by Requirement 1, the AD requires a disassembly, inspection and lubrication in accordance with the disassembly SB within 180 days or 400 flight hours. (Requirement 2.)\n\n- All inspection findings must be reported to Bombardier within 14 days of each inspection. (Requirement 3.)\n\n- Completing the full disassembly/inspection/ lubrication SB (SB 700-1A11-27-025 or SB 700-27-067) is treated as terminating action for the AD. (\"Terminating Action\".)\n\n- The AD includes a Table 1 listing specific GT411-3800-7 unit serial numbers that have already been returned from the vendor as greased bearings; those listed units are not required to do the initial short-interval inspections (Requirements 1a–1c) but must comply with Requirement 2.\n\n- Time limits: initial inspection for Requirement 1a must be done within 10 flight cycles or 50 flight hours (whichever first) after the AD effective date; follow-up inspections and disassembly have separate, staggered deadlines (see \"Compliance\" section).\n\n\nWhy the regulator says it matters (stated safety rationale)\n\n- The background states that during maintenance a bolt connecting a PCU to an elevator was found fractured; the bearing at the PCU rod end had seized and damaged the fitting bushing, which led to the bolt fracture. Inspection found two more seized joints on other in-service aeroplanes. The AD says failure of bolts in both PCUs on one side could disconnect the elevator control surface and produce flutter and loss of the aircraft. The AD therefore mandates inspection, lubrication and disassembly/inspection work to detect seizure or damage and remediate it.\n\n\nPractical effects, costs and incentives (mechanics, who pays, who decides, behaviour changes)\n\n- Who pays: the operator/aircraft owner pays for the inspections, lubrication, disassembly, labour, line time and any rectification parts or vendor work. If operators send units to the vendor, that vendor work may replace some in-service inspections (as reflected in Table 1). \n\n- Who decides/controls implementation: operators must follow the Bombardier SBs cited; the AD accepts later revisions of those SBs only if approved by the Chief, Continuing Airworthiness (and references Transport Canada approval where applicable). That gives the regulator a gatekeeping role over which SB updates qualify. Completing the disassembly SB is the regulator-accepted terminating action; otherwise repeated inspections remain mandatory. \n\n- Behaviour changes required: operators must add short-term inspections and follow-on disassembly inspections to their maintenance programmes for affected PCUs, report inspection findings to Bombardier, and, if damage is found, follow Bombardier's disposition instructions before further flight. Some units listed in Table 1 are exempt from the short-interval inspections because vendor work has already been performed, but they still must meet the disassembly requirement.\n\n\nTrade-offs, risks and implementation notes\n\n- Direct costs: line maintenance time, potential removal and shop-level disassembly, parts and vendor charges, aircraft downtime. Those costs are concentrated on operators of the affected fleet and the vendor/maintenance market stands to gain work (concentrated benefit). \n\n- Compliance burden: multiple short deadlines (e.g. within 10 flight cycles/50 flight hours; then 90 days/200 hours; then 45 days/100 hours; etc.) create scheduling complexity for operators and may force out-of-sequence maintenance. There is also a reporting requirement (within 14 days) that operators must resource. \n\n- Substitution/operational effects: operators can choose to send units to a vendor for the SB disassembly/repair; if they do, Table 1 shows that vendor-performed greasing can remove some short-interval inspections. That creates a commercially available compliance path (vendor repair) that may be more predictable but could raise market concentration in maintenance providers for these PCUs. \n\n- Implementation risk: availability of qualified maintenance facilities, lead times for spare PCUs or vendor slots, and the need to adopt SB revisions approved by the Chief may affect how quickly operators can meet deadlines. \n\n- Regulatory discretion: the AD accepts ‘‘later revisions approved by the Chief, Continuing Airworthiness’’ — that central approval controls which SB updates are acceptable and can affect compliance options. \n\n- Safety benefit is narrowly targeted: the AD addresses seizure/damage of the PCU rod-end bearing and related bolt fracture risk; actions required are inspections, lubrication and, where required, disassembly and repair. These actions are directly tied to the stated failure mode and to preventing loss of elevator control.\n\n\nReference points in the AD text\n\n- Requirements 1 and 2 set out the inspected parts and the SBs to use. Requirement 3 requires reporting to Bombardier. The Table 1 list and the \"Terminating Action\" paragraph govern exemptions and what ends the AD. The \"Compliance\" paragraph sets the specific time limits for each action. The \"Background\" paragraph describes the fractured bolt and seized bearing incident that prompted the AD."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts","history":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts/history","analysis":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts/analysis","conflicts":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts/conflicts","importantCases":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts/important-cases","documents":"/api/acts/ad-bd-700-1-elevator-pcu-attachment-bolts/documents"}}