Discussion
What Events Have Caused This AD?
The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, reported an incident of an in-flight fire on a Model S10- VT sailplane. The accident investigation revealed that the fire was not contained in the engine compartment. The manufacturer conducted a design review and determined that modifications to the fuel and oil system and the firewall design will significantly reduce the potential for a fire to ignite in the engine compartment and increase the containment of an engine fire in the engine compartment.
This condition caused us to issue AD 2002-22-04, Amendment 39-12928 (67 FR 66547, November 1, 2002). AD 2002-22-04 requires the following on certain Model S10-VT sailplanes:
--Modify the engine compartment fuel and oil system; and
--Modify the firewall by sealing all gaps.
Although Stemme Models S10 and S10-V sailplanes have a different engine installation (non-turbocharged), they are of similar type design as Stemme Model S10-VT sailplanes. We have determined that similar modifications should also be incorporated on these sailplanes. The LBA has determined that these modifications are not mandatory for sailplanes registered outside of the United States.
What Is the Potential Impact if FAA Took No Action?
If this condition is not prevented, there is potential for a fire to ignite in the engine compartment and spread into the cockpit. Such a condition could lead to loss of control of the sailplane.
Has FAA Taken Any Action to This Point?
We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all Stemme Models S10 and S10-V sailplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on January 14, 2003 (68 FR 1805). The NPRM proposed to require you to modify the engine compartment fuel and oil system and firewall.
Was the Public Invited To Comment?
The FAA encouraged interested persons to participate in the making of this amendment. We received one comment in support of the NPRM.
FAA's Determination
What Is FAA's Final Determination on This Issue?
We carefully reviewed all available information related to the subject presented above and determined that air safety and the public interest require the adoption of the rule as proposed except for the changes discussed above and minor editorial corrections. We have determined that these changes and minor corrections:
--Provide the intent that was proposed in the NPRM for correcting the unsafe condition; and
--Do not add any additional burden upon the public than was already proposed in the NPRM.
How Does the Revision to 14 CFR Part 39 Affect This AD?
On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.
Cost Impact
How Many Sailplanes Does This AD Impact?
We estimate that this AD affects 15 sailplanes in the U.S. registry.
What Is the Cost Impact of This AD on Owners/Operators of the Affected Sailplanes?
We estimate the following costs to accomplish the modifications:
Labor cost
Parts cost
Total cost on U.S. operators
Total cost per airplane
10 workhours x $60 per hour = $600.
$620
$1,220
$1,220 x 15 = $18,300.
What is the Compliance Time of This AD?
The compliance time of this AD is "within the next 50 hours time- in-service (TIS) or 6 months after the effective date of this AD, whichever occurs first."
Why Is the Compliance Time of This AD Presented in Both Hours TIS and Calendar Time?
The unsafe condition on these sailplanes is not a result of the number of times the sailplane is operated. Sailplane operation varies among operators. For example, one operator may operate the sailplane 50 hours TIS in 6 months while it may take another operator 12 months or more to accumulate 50 hours TIS. For this reason, the FAA has determined that the compliance time of this AD will be specified in both hours TIS and calendar time in order to ensure this condition is not allowed to go uncorrected over time.
Regulatory Impact
Does This AD Impact Various Entities?
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
Does This AD Involve a Significant Rule or Regulatory Action?
For the reasons discussed above, I certify that this action (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); 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. A copy of the final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.
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 Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
FAA amends 39.13 by adding a new AD to read as follows: