AD 2012-14-15

This AD is effective July 19, 2012.

We must receive comments on this AD by September 4, 2012.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: 202-493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

• Non-Pilatus aircraft-related: Albert Ma, Aerospace Engineer, Wichita Aircraft Certification Office, FAA, 1801 S. Airport Road, Room 100, Wichita, Kansas 67209; phone: (316) 946-4151; fax: (316) 946-4107; email: albert.ma@faa.gov.

• Pilatus aircraft-related: Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4059; fax: (816) 329-4090; email: doug.rudolph@faa.gov.

We received a report that during flight test trials of SBAS-capable aircraft using a similar Honeywell GPS sensor with the same software as the Honeywell International, Inc. Model KGS200 Mercury 2 WAAS GNSSU, a software problem occurred that could result in misleading information during LP, LPV, or SBAS LNAV/VNAV approaches.

Investigation found the GPS receiver could compute an incorrect ionospheric correction and error estimate such that the error estimate no longer bounds the error and the downstream monitor cannot detect it. This can potentially lead to hazardously misleading information.

The software problem is due to a mathematical rounding error, which results in misleading information.

At this time, the only type-certificated airplanes that the product is installed in is Pilatus PC-12/47E airplanes.

This condition, if not corrected, could result in misleading information during instrument meteorological conditions, which could prevent the aircraft from performing safe instrument approach procedures, causing controlled flight into terrain.

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This AD requires incorporating airworthiness limitations and placards that prohibit LP, LPV, and SBAS LNAV/VNAV approaches until the software problem is corrected.

We consider this AD interim action. If and when new software is developed, the FAA will evaluate this software and may take further rulemaking action.

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because this condition, if not corrected, could result in misleading information during instrument meteorological conditions, which could prevent the aircraft from performing safe instrument approach procedures, causing controlled flight into terrain. Therefore, we find that notice and opportunity for prior public comment are impracticable and that good cause exists for making this amendment effective in less than 30 days.

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number FAA-2012-17129 and Directorate Identifier 2012-CE-027-AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

We estimate that this AD affects 195 GNSSU installed on, but not limited to, PILATUS AIRCRAFT LTD. Model PILATUS PC-12/47E airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

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.

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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):