GEnx Fan OGV Exemption

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May15th, 2012
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

Agenda

• 14 CFR Part 33.83 Background

• Fan Stator and OGV Description

• Analysis of Structural Redundancy to Support 

Exemption

• Summary
14 CFR Part 33.83 Background
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

• In order to meet customer operation specification, GE would 

like increase ground wind operational envelope.

• Fan OGV exceeds 14 CFR Part 33.83(d) material endurance 

limit requirement for the GEnx-1B and 2B under high 

crosswind conditions with separated inlet airflow.

• Request for Exemption submitted to Federal DMS on April 4, 

2012.

o Written against GEnx-2B and GEnx-1B78/P2.

o Would like to modify Exemption Request to include all GEnx 

models.
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

GEnx-2B - Fan Blade/OGV Aeromechanics Limited

• GEnx-2B unrestricted 

zone limited to 25 kts

due to Fan blade and 

Fan OGV responses

• Revised GEnx-2B Fan 

blade report supports 

30 kts.

• Exemption on Fan OGV 

would allow 

unrestricted zone 

extension to 30 kts
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

Fan OGV 33.83 % Limits Overview

Both 1B and 2B exceed endurance limits with high crosswind conditions

• Limits exceeded only during High Crosswind conditions

• No Engine issues when operated within Certified Limits
Fan Stator and OGV Description
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

GEnx Fan X-section

Fan OGV

Fan Hub 

Frame

QEC* Joint

* Quick Engine Change

AFT Fan 

Case/Attachment
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

Fan Stator Assembly

• Fan OGV Assembly is a highly 

redundant system with 

multiple load paths

• Each Fan OGV has 4 OD and 4 

ID attachment points

• Quantity of OGVs determined 

by Aero/Acoustics, not 

structural requirements

Fan 

OGV’s

Fan Hub 

Frame

AFT Fan Case

QEC Joint

Forward Engine 

Mount
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

FLA

Type 1

Type 6

Nom. 

Titanium Pylon OGVs

Fwd Engine Mount

• Titanium material capability 

needed below Fwd engine 

mount location – highest 

loads. 

• Balance of OGV’s are of 

light-weight aluminum due 

to lower loads.

Limiting Crosswind OGV
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GE Aviation

GE PROPRIETARY INFORMATION 5/16/2012

OGV Description

• Multiple Attachment Points 

extend redundancy - 4 

each at the OD and ID
OGV Redundancy Analysis
Worst Case Analysis of Distressed OGV

Footer

Load Path Cut in Limiting Area 

• Analyzed worst case Loading 

Condition for any attachment 

separation.

• Adjacent Ti OGV experienced 

maximum increase of 1.4%

Worst Case Distressed OGV

Titanium OGVs
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GE Aviation

GE PROPRIETARY INFORMATION T Davis 5/16/2012

Back-to Back Analysis Results

Baseline Configuration Cut Load Path Case

Location of 1.4% Increase
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GE Aviation

GE PROPRIETARY INFORMATION T Davis 5/16/2012

Summary

• Redundancy of OGV frame validated by analysis.

• Worst Case Engine Testing also confirms redundancy.