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====== General Aviation Lead Fuel =====

==== Links/Documents ====
 * {{ :atmos:pestiside:delene_leademissions_proposal_20250328.pdf |Aerospace Seed Funding Proposal}}

==== Airport Lead Filter Collection ====
 * {{https://1drv.ms/x/c/52158434cd7bae56/IQBxiZztZ2lwT7wIT7zp2L9WAd2UJ6rrenfbCQzaPkPZyTg?e=VAKzAJ |Lead Filter Data}}
==== UND Fleet Leaded Fuel Analysis ====
=== Engineering Performance, FAA requirements, Certification requirements ===

During aircraft certification, manufacturers must demonstrate that the aircraft can safely operate using aircraft specific fuel types. For general aviation aircraft, this is typically 100LL, while transport category aircraft tend to use Jet A. This demonstration is conducted alongside the aircrafts certification program and establishes the approved fuels in the aircrafts Type Certificate Data Sheet, which defines the approved configuration, and operational limits to maintain airworthiness for the specific aircraft make and model. 
Once the aircraft is certified, the approved fuel types become a part of the aircraft's type design, with unapproved fuel types rendering an aircraft unairworthy unless the fuel type has been approved through an additional pathway. FAA approval must be met during the aircraft manufactured original type certification, or a supplemental approval process. 
This process is called the Supplemental Type Certificate or an STC, which allows approved changes to the original aircraft design. This process could allow a different fuel type to be approved and airworthy provided the FAA finds reliability in this change. 

In addition to certification approvals, the FAA provides regulations for fuel efficiency certification under CFR 14 part 38 titled “Airplane Fuel Efficiency Certification.” Furthermore, the FAA produces advisory circulars which provide industry recommendations for fuel testing, manufacturer limitations, and provide guidance for compliance with regulations. 

CFR :: 14 CFR Part 38 -- Airplane Fuel Efficiency Certification (FAR Part 38)
- https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-38

AC 20-24C Approval of Propulsion Fuels and Lubricating Oils 
- https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2020-24C.pdf


=== With aircraft/environment impact issue.  What is the fuel like.  Compare leaded and unleaded chemistry for generator aircraft fuels. ===
  Emissions from leaded aviation fuel are the largest remaining source of lead pollution in the air, soil, and water. Being exposed to lead in the air can cause serious and permanent health problems. People who live close to airports that use leaded fuel are at a higher risk because of the increased amount of lead released into the air. Living within one kilometer of an airport can greatly increase this risk, mainly because ground operations like takeoffs, taxiing, idling, engine startup, and landings release the most lead emissions. 

Studies have found that children who are exposed to these emissions often have higher levels of lead in their blood, which is a major health concern. Some of the effects include lower IQ, reduced academic performance, behavioral problems, and poorer cognitive function. Although more research is still needed on how lead exposure affects adults, it is believed that it may increase the risk of death and cardiovascular disease. 

Tetraethyl lead (Pb(C₂H₅)₄) is added to aviation gasoline used in piston-engine aircraft to prevent engine knocking and to raise octane levels. While fuel with less lead can be made, it becomes harder to meet the high-octane requirements needed for high-performance aircraft. Switching to unleaded aviation fuel is challenging for several reasons, including cost, FAA safety regulations, and engine compatibility. Creating a fuel that meets safety standards, provides enough octane for proper engine performance, and is affordable is a complicated process. 

==== Papers ====
  * [[https://www.combustion-engines.eu/The-future-of-leaded-aviation-fuel-navigating-the-challenges-of-transition,210465,0,2.html|The future of leaded aviation fuel: navigating the challenges of transition]]