We have received a report indicating that all four cockpit flight panel displays went blank simultaneously during flight, then recovered without any flightcrew action after approximately 74 seconds, on a Gulfstream Model GV-SP series airplane. Two similar incidents occurred on the ground. An engineering investigation revealed a software problem on the Honeywell Primus Epic system, which can cause a temporary loss of data from the cockpit display units. Loss of the cockpit display units will result in a reduction of the flightcrew's situational awareness, and possible loss of control of the airplane. The engineering investigation also revealed noise interference on the avionics standard communication bus (ASCB), which is a part of the Honeywell Primus Epic system. Noise interference, if not corrected, can possibly interfere with the display recovery after a blanking event, and consequently extend the time that the cockpit displays remain blank.
Other Relevant Rulemaking
We determined that since the Honeywell Primus Epic system also is installed on Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 170 series airplanes, those airplanes are subject to an unsafe condition similar to that addressed in this AD. In light of that determination, we issued AD 2004-26-12, amendment 39-13924 (69 FR 78300, December 30, 2004), to address that unsafe condition on that airplane model. We may consider additional rulemaking on other airplane models having the Honeywell Primus Epic system that also exhibit a similar unsafe condition.
Relevant Service Information
We have reviewed Gulfstream G500 Alert Customer Bulletin 2, dated October 27, 2004; and Gulfstream G550 Alert Customer Bulletin 2, dated October 27, 2004. The customer bulletins describe procedures for inspecting the ASCB for any noise interference and contacting the manufacturer if any noise interference indications are found during the inspection.
We have also reviewed Gulfstream G500 Airplane Flight Manual (AFM) GAC-AC-G500-OPS-0001, Revision 7, dated December 28, 2004; and Gulfstream G550 AFM GAC-AC-G550-OPS-0001, Revision 9, dated December 28, 2004. The AFM revisions describe procedures to recover the cockpit display units in the event that all four cockpit display units go blank during flight. Additionally, these AFM revisions describe procedures to ensure that the flightcrew is aware that dispatch of any flight with any of the following display units inoperative is prohibited: the integrated standby flight display (SFD), very high frequency (VHF) 1, very high frequency omnidirectional range (VOR) 1, or air traffic control (ATC) 1. The AFM revisions also describe procedures to advise the flightcrew that, during the use of Taxi/Before Takeoff, Descent, and Before Landing checklists, the briefings (takeoff and approach) should include the possibility of the loss of all cockpit display units and the subsequent transition to the use of the standbyinstruments.
In addition, we have reviewed Gulfstream G500 Aircraft Service Change 902; and Gulfstream G550 Aircraft Service Change 902; both dated December 30, 2004. The aircraft service changes describe procedures to install software updates to the Honeywell Primus Epic systems and for submitting the service reply card, and specify concurrent accomplishment of Gulfstream G500 Aircraft Service Change 043, dated December 30, 2004; and Gulfstream G550 Aircraft Service Change 043, dated December 30, 2004; as applicable. Gulfstream G500 Aircraft Service Change 043 and Gulfstream G550 Aircraft Service Change 043 describe procedures for installing hardware upgrades to the Honeywell Primus Epic systems. The hardware upgrades include upgrading and retrofitting display controllers, display units, a display driver unit, and a data management unit in addition to replacing an existing circuit breaker with a new circuit breaker. Installing the software update and the hardware upgrade will allow removal of certain AFM revisions and will end the repetitive inspections of the ASCB.
Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.
FAA's Determination and Requirements of This AD
The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. Therefore, we are issuing this AD to prevent a software error from blanking the cockpit display units, which will result in a reduction of the flightcrew's situational awareness, and possibly loss of control of the airplane. We are also issuing this AD to address noise interference in the avionics standard communication bus (ASCB), which can interfere with the display recovery after a blanking event and consequently extend the time that the displays remain blank. In addition, we are issuing this AD to ensure that the flightcrew is advised of the procedures necessary to address blank cockpit display units, and to ensure that adequate standby instrument systems are available to safely complete the flight.
This AD requires doing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and the Customer Bulletins."
Differences Between the AD and the Customer Bulletins
Operators should note that, although the Accomplishment Instructions of the referenced customer bulletins describe procedures for submitting a sheet recording compliance with the customer bulletin, this AD will not require those actions. The FAA does not need this information from operators.
Operators should note that, although the Modification Instructions of the referenced aircraft service changes describe procedures for submitting a service reply card, this AD will not require those actions. The FAA does not need this information from operators.
Although the customer bulletins specify that operators may contact the manufacturer for disposition if any noise interference indications are found during the inspection of the ASCB, this AD requires operators to repair the ASCB according to a method approved by the FAA.
The customer bulletins specify a one time inspection; however, they do note that a recurring inspection will be added to the applicable airplane maintenance manual (AMM). The recurring inspection interval in the applicable AMM is specified as 60 days, the same as this AD.
The customer bulletins state that a certain number of Gulfstream Model GV-SP series airplanes with specific serial numbers are affected. This AD also specifies certain additional airplanes with serial numbers that are not stated in the customer bulletin. These additional airplanes may also be subject to the unsafe condition.
Clarification of AFM Revisions
As indicated in Note 1 of this AD, operators may accomplish the AFM revisions required by this AD by inserting a copy of Gulfstream G500 AFM GAC-AC-G500-OPS-0001, Revision 7, dated December 28, 2004, or Gulfstream G550 AFM GAC-AC-G550-OPS-0001, Revision 9, dated December 28, 2004, into the applicable AFM. Future general revisions to the AFM must contain the identical procedures specified in the applicable sections of the AFM revisions required by this AD.
FAA's Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.
Comments Invited
This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2005-20280; Directorate Identifier 2004-NM-254-AD" atthe beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of our docket Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, "General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.
For the reasons discussed above, I certify that the regulation:
1. Is not a "significant regulatory action" under Executive Order 12866;
2. Is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
We prepared a regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39-AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. The FAA amends 39.13 by adding the following new airworthiness directive (AD):