Airmotive Engineering 

Corporation (AEC) Meeting 

with FAA and NTSB February 

14, 2013 

Regarding

Head-Barrel Separations 

On

AEC631397 Cylinders

 Other Parts We Make
Agenda 

• Key Points

• Meeting Objectives

• NTSB Meeting Summary

• Situation Background

• Industry Wide Failure History

• Cylinder Safety Program Presentation

• Finite Element Analysis Presentation

• Statistical Analysis Discussion

• Consequences of Proposed NPRM

• Discussion 
Key Points

• No Fatalities, No Injuries and No Accidents

• The Design of AEC Cylinders Exceeds FAA Airworthy 

Standards

• The Manufacture of AEC Cylinders is Within Design 

Parameters

• The Operating Environment is the Cause of the Failures

• Our Cylinders Are Safe When Operated Within Legal Limits

• Field Replacement of Cylinders Causes Significant Safety 

Risks

• Head Barrel Separations Are an Industry Wide Issue Caused 

by Adverse Operating Conditions
Meeting Objectives

• Prevent an Unwarranted Action on AEC 520 TITAN 

Cylinders

• Prevent Unnecessary Safety Risks Caused by 

Unwarranted Action

• Demonstrate That the Root Cause of Head Barrel 

Separations is Adverse Operating Conditions

• Establish That the Design and Manufacture of AEC 

Cylinders Exceeds FAA Airworthiness Standards

• There is No Basis for Removal of AEC Cylinders 

from the Field
NTSB Meeting Summary

• AEC Met NTSB Members on Feb. 7th 

• They Agreed That A-12-7 Was Written Prior to Testing 

Results Indicating Root Cause as Operating Conditions

• The NTSB Agreed That There Have Been No Fatalities 

as a Result of a Head Barrel Separation of a New Titan 

520 Cylinder

• They Agreed That Removal of AEC Cylinders from the 

Field Prior to TBO Was Unwarranted

• They Agreed The Scope of A-12-7 Should Be Reduced

• The NTSB Suggested the Best Path to Reducing the 

Scope of A-12-7 is for the FAA to Propose It
Situation Background

• Cylinder Characteristics 

− Approximately 80% Related to Piston Engine Parts of 

SDRs Relate to Cylinders

– Exposed To Severe Temperature Cycles Even When 

Operated Within Limits

– Sub Zero Starting Environment To Exposure To More 

Than 3000 °F Combustion Temperatures

– High Combustion Pressures – Up To 1000 PSI Peak 

Pressures

– Air Cooled

– Has A Joint Between Aluminum Head And Steel 

Barrel

– FAA-PMA Certificated Replacement Parts Must Be 

Technically Equivalent to the TC Part
Situation Background

• FAA SDR Lists More Than 1200 Head-ToBarrel Separations For Continental 

Manufactured Cylinders 

• FAA and AEC Data Show Less Than 40 

AEC New TITAN 520 Cylinder Head-ToBarrel Separations
Situation Background

Graph 1

OEM And AEC 

520 Cylinder 

Failure History
Situation Background

• No New AEC TITAN 520 Cylinder 

Manufactured After June 2008 Has 

Experienced a Head Barrel Separation

• No Head Barrel Separations on New AEC 

TITAN 520 Cylinders Have Been Reported 

Since August 2011

 
Situation Background

• AEC’s Experience with Head Barrel 

Separations:

− ZERO Fatalities with New 520 TITANS

− No Injuries with New 520 TITANS

− No Accidents with New 520 TITANS

− Head to Barrel Separations:

• Result in Approximately 20% Loss of 

Power

• Allows Sufficient Power to Safely 

Land
Cylinder Safety Program 

Presentation 

• AEC Accomplished Extensive Root Cause Tests 

And Analysis Since Publication of A-12-7 

−Testing Recommended by NTSB

−Root Cause Identified as Out Of Limits 

Operation

−Validates Cylinders Safe When Operated 

Legally

−Presented To NTSB Lab And Engineering 

Personnel with a Positive Response
Agenda 

• Key Points

• Meeting Objectives

• NTSB Meeting Summary

• Situation Background

• Industry Wide Failure History

• Cylinder Safety Program Presentation

• Finite Element Analysis Presentation

• Statistical Analysis Discussion

• Consequences of Proposed NPRM

• Discussion 
Finite Element Analysis

• AEC Contracted Don Gillespie from Delta 

G Design to Perform Finite Element 

Analysis of the Head to Barrel Interface

• Varied Thread Interferences Were 

Modeled to Correlate Engine Test Data

• Delta G Design Will Now Present Their 

Presentation
Agenda 

• Key Points

• Meeting Objectives

• NTSB Meeting Summary

• Situation Background

• Industry Wide Failure History

• Cylinder Safety Program Presentation

• Finite Element Analysis Presentation

• Statistical Analysis Discussion

• Consequences of Proposed NPRM

• Discussion 
Statistical Analysis

• Predictions vs. Actual from Dr. Don 

Kenton’s Report 2013-02-1 

0

5

10

15

20

25

30

35

Group Post 6-2

Group 6-2
Consequences of Proposed NPRM

• Because It Does Not Consider the Root 

Cause of Operating Conditions:

– Will Cause An Unwarranted Burden On GA 

Public (Approximately 10,000 Aircraft)

– Field Removal and Replacement of a Large 

Number of Safe Cylinders Will Result in 

Unnecessary Accidents

– The Root Cause of Adverse Operating 

Conditions Will Continue Unaddressed
Key Points

• No Fatalities, No Injuries and No Accidents

• The Design of AEC Cylinders Exceeds FAA Airworthy 

Standards

• The Manufacture of AEC Cylinders is Within Design 

Parameters

• The Operating Environment is the Cause of the Failures

• Our Cylinders Are Safe When Operated Within Legal Limits

• Field Replacement of Cylinders Causes Significant Safety 

Risks

• Head Barrel Separations Are an Industry Wide Issue Caused 

by Adverse Operating Conditions
Meeting Objectives

• Prevent an Unwarranted Action on AEC 520 TITAN 

Cylinders

• Prevent Unnecessary Safety Risks Caused by 

Unwarranted Action

• Demonstrate That the Root Cause of Head Barrel 

Separations is Adverse Operating Conditions

• Establish That the Design and Manufacture of AEC 

Cylinders Exceeds FAA Airworthiness Standards

• There is No Basis for Removal of AEC Cylinders 

from the Field
AEC/FAA/NTSB Dialog

• Discussion