Results
86-21-03: 86-21-03 BRITISH AEROSPACE: Amendment 39-5421. Applies to BAe Model 125- 800A series airplanes, serial numbers listed in BAe Service Bulletin 24-250-(3017D), dated April 8, 1985, certificated in any category. Compliance is required within 90 days after the effective date of this AD. To prevent a potential fire hazard associated with chafing of electrical wiring, accomplish the following, unless previously accomplished: A. Inspect and replace, as necessary, the affected electrical cables and install the protective treatment to adjacent structures in accordance with BAe Service Bulletin 24-250- (3017D), dated April 8, 1985. B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Northwest Mountain Region. C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by the AD. All persons affected by this directive who have not already received the appropriate service bulletin from the manufacturer may obtain copies upon request to British Aerospace, Inc., Librarian, Box 17414, Dulles International Airport, Washington, D.C. 20041. This document may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. This Amendment becomes effective October 24, 1986.
2016-23-06: We are adopting a new airworthiness directive (AD) for various aircraft equipped with a BRP-Powertrain GmbH & Co KG (formerly Rotax Aircraft Engines) 912 A series engine. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as a manufacturing defect found in certain carburetor floats where an in-flight engine shutdown and forced landing could occur when the affected cylinder had reduced or blocked fuel supply. We are issuing this AD to require actions to address the unsafe condition on these products.
2010-23-14: We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Several cases of corrosion in lower structural members of the passenger door have been reported. It was subsequently determined that a drainage ramp (constructed from resin) had deteriorated with time and was retaining moisture. * * * Corrosion left undetected could eventually affect the structural integrity of the door and surrounding structure. We are issuing this AD to require actions to correct the unsafe condition on these products.
79-10-02: 79-10-02 SHORT BROTHERS LIMITED: Amendment 39-3457. Applies to Model SD3-30 airplanes, S/N SH3002 through SH3019, certificated in all categories, which have low blade angle pitch mechanism support bracket, P/N SD3-49-0784, or P/N SD3-49-0784xB installed. Compliance is required as indicated, unless already accomplished. To prevent propeller blade angle from increasing beyond the flight setting, accomplish the following: (a) Within the next 30 hours time in service after the effective date of this AD, remove each low blade angle pitch mechanism support bracket, P/N SD3-49-0784 or P/N SD3- 49-0784xB, and inspect it for cracks using the dye penetrant procedure or an equivalent FAA- approved procedure, in accordance with paragraph 2.A., "Accomplishment Instructions", of Short Brothers Service Bulletin No. SD3-61-A05, dated August 2, 1978, or an FAA-approved equivalent. (b) Within the next 300 hours time in service after bracket reinstallation in accordance with paragraph (c)(1) of this AD or bracket replacement in accordance with paragraph (d)(1) of this AD, and thereafter at intervals not to exceed 300 hours from the last inspection, visually inspect support bracket, P/N SD3-49-0784 or P/N SD3-49-0784xB, for cracks in accordance with paragraph 2.A.10 of the Short Brothers Service Bulletin No. SD3-61- A05 dated August 2, 1978, or an FAA-approved equivalent. (c) If, during any inspection required by paragraph (a) of this AD, no cracks are found (1) Reinstall support bracket, P/N SD3-49-0784 or P/N SD3-49-0784xB in accordance with Short Brothers Service Bulletin No. SD3-61-A05 dated August 2, 1978, or an FAA-approved equivalent and accomplish the repetitive inspections required by paragraph (b) of this AD; or (2) Install a modified support bracket, P/N SD3-49-0902 or P/N SD3-49- 0902xA in accordance with Short Brothers Service Bulletin No. SD3-61-05 dated September 27, 1978, or an equivalent approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa and Middle East Region. (d) If, during any inspection required by this AD, any cracks are found, remove the cracked bracket from service and - (1) Replace the cracked support bracket with a crack-free, new or used support bracket of the same part number, and accomplish the repetitive inspections required by paragraph (b) of this AD. (Before installation of a used support bracket, inspect it in accordance with the method specified in paragraph (a) of this AD to ensure that it is crack-free); or (2) Replace the cracked bracket with a modified support bracket, P/N SD3- 49-0902 or P/N SD3-49-0902xA, in accordance with Short Brothers Service Bulletin No. SD3- 61-05 dated September 27, 1978, or an equivalent approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa and Middle East Region. (e) Upon installation of a modified support bracket, P/N SD3-49-0902 or P/N SD3- 49-0902xA, in accordance with Short Brothers Service Bulletin No. SD3-61-05 dated September 27, 1978, or an equivalent approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Region, inspections required by paragraph (b) of this AD may be discontinued. (f) Upon request of an operator, the Chief, Aircraft Certification Staff, FAA, Europe, Africa and Middle East Region, c/o American Embassy, Brussels, Belgium, may adjust the repetitive inspection interval specified in paragraph (b) of this AD or approve modifications equivalent to that specified in paragraphs (c), (d), and (e) of this AD provided that such requests are made through an FAA maintenance inspector and the request contains substantiating data to justify the request for that operator. This amendment becomes effective May 14, 1979.
94-21-03: This amendment adopts a new airworthiness directive (AD), applicable to certain Jetstream Model 4101 airplanes, that requires installation of a placard near the decouple control handle for the elevator control system to ensure that the pilots are made aware that maintenance action is required to reset the disconnect unit once the decouple control handle has been pulled. This amendment is prompted by a report that, if the decouple control handle for the elevator control system is pulled, the lock linkage will remain unlocked until it is reset during maintenance. The actions specified by this AD are intended to prevent reduced controllability of the airplane due to loss of the mechanical linkage between the pilots' elevator controls, and each pilot having control authority over only one-half of the elevator control system.
2016-21-06: We are superseding Airworthiness Directive (AD) 2015-02-23, for certain Bombardier, Inc. Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), and CL-600-2B16 (CL-601-3A and CL-601-3R Variants) airplanes. AD 2015-02-23 required repetitive inspections for fractured or incorrectly oriented fasteners on the inboard flap hinge-box forward fittings on both wings, and replacement of all fasteners if necessary. This new AD also requires replacement of the fasteners, which terminates the requirements of this AD. This AD was prompted by reports of incorrectly oriented fasteners. We are issuing this AD to prevent incorrectly oriented or fractured fasteners, which could result in detachment of the flap hinge-box and the flap surface, and consequent reduced controllability of the airplane.
2001-15-05: This amendment adopts a new airworthiness directive (AD), applicable to all Aerospatiale Model ATR42-200, -300, -320, -500, and ATR72 series airplanes, that requires a revision of the Airplane Flight Manual to add instructions that prohibit the flightcrew from selecting the reverse position on the engines in the event of propeller thrust dissymmetry. The actions specified by this AD are intended to ensure that the flightcrew is advised of the hazard associated with selecting reverse thrust during propeller thrust dissymmetry, which could result in reduced controllability of the airplane during landing. This action is intended to address the identified unsafe condition.
2022-26-01: The FAA is adopting a new airworthiness directive (AD) for certain GE Aviation Czech s.r.o. (GEAC) M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-11S, M601F, H75-100, H75-200, H80, H80-100, H80-200, H85-100, and H85-200 model turboprop engines. This AD was prompted by reports of cracks in dilution tube weld areas of the combustion chamber outer liner. This AD requires initial and repetitive borescope inspections (BSIs) of the dilution tube weld areas of the combustion chamber outer liner and, depending on the results of the inspections, replacement of the combustion chamber outer liner with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.
2001-13-26: This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10-10, -15, -30, and -40 series airplanes, and Model MD-10-10F and -30F series airplanes, that requires a general visual inspection to detect chafing or damage of the feeder cables of the external ground power in the forward cargo compartment between certain fuselage stations; and repair, if necessary. This amendment also requires installation of spiral wrap on the feeder cables of the external ground power. This action is necessary to prevent chafing of the feeder cables during removal of the sump panels of the cargo floor, which could result in electrical arcing and damage to adjacent structure, and consequent smoke and/or fire in the forward cargo compartment. This action is intended to address the identified unsafe condition.
2001-15-06: This amendment supersedes an existing airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that currently requires modification of the forward and aft evacuation slide systems by replacing the Velcro restraints for the support logs with frangible link restraints. This amendment reduces the time to accomplish the modification from 3 years to 9 months. 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 prevent the ingestion of sill support-log material into the aspirator of the evacuation slide, which could result in failure of the slide to inflate. The incorporation by reference of Airbus Service bulletin A320-25-1215, dated April 29, 1999, as listed in the regulations was approved previously by the Director of the Federal Register as of March 30, 2000 (65 FR 9212, February 24, 2000).
2016-22-15: We are superseding Airworthiness Directive (AD) 2012-24-06 for certain Saab AB, Saab Aeronautics Model 340A (SAAB/SF340A) and SAAB 340B airplanes. AD 2012-24-06 required replacing the stall warning computer (SWC) with a new SWC that provides an artificial stall warning in icing conditions, and modifying the airplane for the replacement of the SWC. This new AD adds airplanes to the applicability, and adds requirements to replace the existing SWCs with new, improved SWCs, and to modify the airplane for the new replacement of the SWC. This new AD also reduces the compliance time for replacing the SWCs. This AD was prompted by a determination that airplanes with certain modifications were excluded from the applicability in AD 2012-24-06, and are affected by the identified unsafe condition; and that the SWC required by AD 2012-24-06 contained erroneous logic. We are issuing this AD to prevent natural stall events during operation in icing conditions, which could result in loss of control of the airplane.
2016-22-12: We are adopting a new airworthiness directive (AD) for all Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/ 350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1- H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes. This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as wear and cracks on the stabilizer-trim attachment and structural components. We are issuing this AD to require actions to address the unsafe condition on these products. [[Page 76846]]
2001-13-27: This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10 and -30 series airplanes. This action requires replacement of a certain circuit breaker in the navigation transfer circuit located on the overhead circuit breaker panel with a certain new circuit breaker; and installation of a new nameplate. This action is necessary to prevent damage to wires or equipment and consequent smoke/fire in the cockpit from heat generated in the wires during an overload condition. This action is intended to address the identified unsafe condition.
89-26-07: 89-26-07 BOEING OF CANADA, LTD., DE HAVILLAND DIVISION: Amendment 39-6422. Docket No. 89-NM-161-AD. Applicability: All Model DHC-7 series airplanes, certificated in any category. Compliance: Required as indicated, unless previously accomplished. To prevent reduced structural capability of the fuselage and subsequent decompression of the airplane, accomplish the following: A. Within 60 days after the effective date of this AD, perform the following inspections and repair, in accordance with de Havilland Service Bulletin 7-53-33, Revision A, dated June 9, 1989: 1. Perform a low frequency ultrasonic inspection for disbonding of the fuselage belly skin doublers, between fuselage stations X248.00 and X535.25 below stringer 20 left and right, in accordance with Inspection Part A of the service bulletin. 2. Visually inspect for looseness or working of the rivets in the vertical skin joints, at fuselage stations X535.25 and X576.25 below stringer 20, leftand right. 3. Visually inspect for looseness or working of the rivets in the fuselage skin joints at station X630.00 around the complete periphery of the fuselage, above and below the passenger and emergency exit doors. 4. Visually inspect for looseness or working of the rivets in the skin longitudinal joint between fuselage stations X424.00 to X484.00 along stringer 20, left and right. Pay particular attention to the lower line of rivets. 5. Repair all loose rivets prior to further flight, in a manner approved by the Manager, New York Aircraft Certification Office, ANE-170, FAA, New England Region. 6. Repair all disbonding prior to further flight, in accordance with the service bulletin. B. Within 90 days after the effective date of this AD: 1. Perform a low frequency ultrasonic inspection for disbonding of the fuselage left and right sidewall skin doublers, between fuselage stations X248.00 and X596.75, between stringer 20 and 10, in accordance withde Havilland Service Bulletin 7-53-33, Revision A, dated June 9, 1989. 2. Repair any disbonding prior to further flight, in accordance with the service bulletin. C. Within 150 days after the effective date of this AD: 1. Perform a low frequency ultrasonic inspection for disbonding of the fuselage roof skin doublers between fuselage stations X248.00 and X630.00, between stringer 10, left and right, in accordance with de Havilland Service Bulletin 7-53-33, Revision A, dated June 9, 1989. 2. Repair any disbonding prior to further flight, in accordance with the service bulletin. D. Within 3 days after accomplishing each of the inspections required by paragraphs A., B., and C., above, report all findings, positive or negative, to the Director, Airworthiness Branch, Transport Canada, Ottawa, Canada; to the manufacturer, Boeing of Canada, Ltd., de Havilland Division, in accordance with de Havilland Service Bulletin 7-53-33, Revision A, dated June 9, 1989; and to the FAA, Manager, New York Aircraft Certification Office, ANE-170, New England Region. E. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, New York Aircraft Certification Office, ANE-170, FAA, New England Region. NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, New York Aircraft Certification Office, ANE-170. F. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing of Canada, Ltd., de Havilland Division, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. These documents may beexamined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or New York Aircraft Certification Office, FAA, New England Region, 181 South Franklin Avenue, Valley Stream, New York. This amendment (39-6422, AD 89-26-07) becomes effective on January 14, 1990.
2016-22-18: We are adopting a new airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. This AD requires a detailed inspection of the forward and aft surfaces on the left and right sides at the cant station 1520 bulkhead for any crack in the upper cap and (cap) doubler, webs and doublers, stiffeners, and the lower tee cap between longerons 3 through 11, and repairs if necessary. This AD was prompted by a report of cracking in various structures in the fuselage cant station 1520 bulkhead. We are issuing this AD to detect and correct cracking in the bulkhead, which could result in reduced structural integrity of the airplane.
50-29-01: 50-29-01 CURTISS-WRIGHT Applies to Model C-46 Series aircraft. Compliance required within 25 hours' time in service after the effective date of this amendment, unless already accomplished within the last 175 hours' time in service, and at intervals thereafter not to exceed 200 hours' time in service from the last inspection. Inspect the lower surface of the wing center section for loose rivets (5/32-A17ST modified brazier head) in the area of the front and rear spars between Stations 82.5 and 107.5. If more than 50 rivets are found loose along either the front or rear spar on either R.H. or L.H. wing center section between the stations mentioned above, they should be replaced immediately following the procedure outlined by Civil Aeronautics Manual 18.20-3(e)(4) (ii)(a). If less than 50 rivets are found loose at any of the above specified locations, the rivets need not be replaced until the time of next major overhaul. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Southern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase. Revised December 28, 1964.
2025-13-02: The FAA is adopting a new airworthiness directive (AD) for all Embraer S.A. Model EMB-545 and EMB-550 airplanes. This AD was prompted by a jamming failure of the main door lock sensor. This AD requires repetitive main door sensor operational tests, repetitive lubrication of the main door sensor mechanism, and on condition actions. The FAA is issuing this AD to address the unsafe condition on these products.August 5, 2025.
2001-14-07: This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires repetitive high frequency eddy current inspections to find cracking of the bulkhead frame support at body station 2598 under the hinge support fittings of the horizontal stabilizer, and repair if cracking is found. These actions are necessary to find and fix fatigue cracking in the frame support, which could result in inability of the structure to carry horizontal stabilizer flight loads and reduced controllability of the horizontal stabilizer. This action is intended to address the identified unsafe condition.
78-16-05: 78-16-05 PRATT & WHITNEY AIRCRAFT: Amendment 39-3274. Applies to all Pratt & Whitney Aircraft JT9D turbofan engines not incorporating an annular strainer element, in accordance with Pratt & Whitney Service Bulletin 4860 dated March 16, 1978, or later FAA approved revision, in the No. 4 bearing compartment. Compliance is required as indicated. To preclude failures of sixth stage turbine disks due to a plugged No. 4 bearing compartment oil scavenge tube, inspect the inside of the No. 4 bearing compartment sump for coke in accordance with the provisions of Pratt & Whitney Alert Service Bulletin No. 4826, dated October 17, 1977, or later FAA approved revision, in accordance with the following schedule: Engines with No. 4 bearing compartments having more than 6000 hours time in service since new or the last cleaning per ASB 4826: 1. Must have a daily visual tailpipe check for oil leakage from the No. 4 bearing compartment. If leakage is noted, the compartment must be inspected prior to further flight. The daily visual check may be discontinued after accomplishing the compartment inspection noted below. A flight crewmember may perform the daily check. NOTE: For the purpose of this AD, compliance with the daily visual check may be shown by recording accomplishment in accordance with FAR 121.380 or by amending the manual required by FAR 121.133 to include the check. 2. Must have the compartment inspected within the next 1500 hours time in service after the effective date of this AD, unless already accomplished, and every 5000 hours time in service thereafter. Engines having unacceptable coke formation in the forward portion of the No. 4 compartment sump area, as defined in Figure 2 of ASB 4826, must have the sump and compartment oil scavenge tube cleaned in accordance with the JT9D Engine Manual, P/N 646028, Section 72-53-00, prior to further flight. Upon request of the operator, an equivalent method of compliance with the requirements of this AD may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, New England Region. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, New England Region, may adjust the initial inspection interval specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Pratt & Whitney Aircraft, Division of United Technologies Corporation, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at the Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at its Headquarters in Washington, D.C., and at FAA, New England Region Headquarters, Burlington, Massachusetts. This amendment becomes effective September 12, 1978.
2016-22-10: We are adopting a new airworthiness directive (AD) for certain Turbomeca S.A. Arriel 1, 1A, 1A1, 1A2, 1B, 1B2, 1C, 1C1, 1C2, 1D, 1D1, 1E, 1E2, 1K1, 1S, and 1S1 turboshaft engines. This AD requires removing the centrifugal impeller and replacing with a part eligible for installation. This AD was prompted by an anomaly that occurred during the grinding operation required by modification TU376, which increases the clearance between the rear curvic coupling of the centrifugal impeller and the fuel injection manifold. We are issuing this AD to prevent failure of the centrifugal impeller, uncontained centrifugal impeller release, damage to the engine, and damage to the helicopter.
2010-18-52: This document publishes in the Federal Register an amendment adopting Emergency Airworthiness Directive (AD) 2010-18-52 which was sent previously to all known owners and operators of MD Helicopters, Inc. (MDHI) Model MD900 helicopters by individual letters. This AD requires visually inspecting the main rotor hub (hub) for a crack. If a crack is found, this AD requires, before further flight, replacing the unairworthy hub with an airworthy hub. Additionally, if a cracked hub is found, this AD requires reporting the finding to the Los Angeles Aircraft Certification Office within 10 days of finding the crack. This AD is prompted by two reports of cracks detected in the hub in the area near the flex beam bolt hole locations during maintenance on two MDHI Model MD900 helicopters. The actions specified by this AD are intended to detect a crack in the hub and prevent failure of the hub and subsequent loss of control of the helicopter.
47-10-30: 47-10-30 LOCKHEED: (Was Mandatory Note 33 of AD-763-3.) Applies to Model 49 Serials 2047 Up to and Including 2075 and to Serials Prior to 2047 Which Have Had 68092 Surge Box Flapper Valves Replaced by 285750 Valves in Accordance With Lockheed SI-15, Dated June 18, 1946. Compliance required prior to April 1, 1947. Replace fuel tank surge box flapper valves, LAC P/N 285750, with new type valve, LAC P/N 285750-600. (LAC Service Instructions 49/SI-15, revised August 10, 1946, and 49/SI-15A, revised August 3, 1946, or subsequent, cover this same subject.)
2001-14-11: This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 747-100 and -200 series airplanes modified by Supplemental Type Certificate SA8622SW, that requires deactivation of the in-flight entertainment (IFE) system. This action is necessary to ensure that the flight crew is able to remove power from the IFE system when necessary. Inability to remove power from the IFE system during a non-normal or emergency situation could result in inability to control smoke or fumes in the airplane flight deck or cabin. This action is intended to address the identified unsafe condition.
2016-22-01: We are adopting a new airworthiness directive (AD) for Schempp-Hirth Flugzeugbau GmbH Models Discus-2a, Discus-2b, Discus-2c, Discus 2cT, Ventus-2a, and Ventus-2b gliders. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition insufficient overlap of the airbrake panels. We are issuing this AD to correct the unsafe condition on these products.
2001-14-15: This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 747-400 series airplanes modified by Supplemental Type Certificate (STC) SA8843SW, that requires modifying the passenger entertainment system (PES) installed by that STC and revising the Airplane Flight Manual. This action is necessary to ensure that the flight crew is able to remove electrical power from the PES when necessary and is advised of appropriate procedures for such action. Inability to remove power from the PES during a non-normal or emergency situation could result in inability to control smoke or fumes in the airplane flight deck or cabin. This action is intended to address the identified unsafe condition.