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Gulfstream Operators: GIV/G450 Outboard Trailing Edge Box Wing Rebate Flange Corrosion 


G450 AMM 57-50-00
GIV AMM 57-50-00
CMP 575019

At West Star Aviation, our Gulfstream specialists have recently experienced several aircraft showing corrosion and cracks within the outboard trailing edge box and wing rebate flange during 24M inspections.

The Computerized Maintenance Program (CMP) Task 575019 & 575020 is required at the 24M Inspection interval on the GIV/G450 aircraft. A borescope is used to inspect the wing plank from edge of rear beam flange to the aft edge of the flange to which trailing edge is attached.

If there are signs of corrosion, then further inspection is required, and the flap, aileron, outboard trailing edge and winglet must be removed to gain access for further evaluation and repair. At this time, there are no Customer Bulletins, Airworthiness Directives or Service Bulletins for this issue.

However, thankfully West Star Aviation has the capability to provide a solution using standard repair processes depending on the level of damage. As an MRO, West Star Aviation must submit findings to Gulfstream Engineering for repair. They will then give a disposition for allowance or repair procedure.

The repair process includes:

  • Cut out corroded area(s) per engineering documents.
  • Make plaster mold casting and send into repair control.
  • Repair control then makes a 3D print as well as first test piece.
  • Verify manufactured piece fits as stated in Eng. Documents.
  • Resubmit new mold if any defects noted (this process can require multiple molds).
  • Once verified, install one-piece CNC-milled doubler on outside of wing skin plank.

Once a repair procedure is completed, an Engineering 8110 is required for return to service.

The severity of the corrosion and cracking observed by West Star Aviation has varied, but in extreme cases, repair labor can range from 650 to 800 hours. West Star has encountered approximately seven instances of this corrosion company-wide (CHA: 4, GJT: 1, ALN: 2).

West Star Aviation can accomplish this inspection and repair at all four full-service facilities (ALN, CHA, GJT and PCD). For more information on this inspection and repair process, please contact any of the specialists listed below:

Gary Freeman

Gary Freeman

Technical Sales Manager

Gulfstream & Learjet

Robert Peyman

Robert Peyman

Director of Technical Sales
Office: 618.258.8090

Larry Marler

Larry Marler

Technical Sales Manager

Jason Mital

Jason Mital

Technical Sales Manager Gulfstream / Lear
Office: 970.248.5236

Jeff Messmer

Jeff Messmer

Technical Sales Manager

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Mark White

RSM, California

Dave Godo

RSM, Ohio Valley

Mark Daniels
Tim Cane
Robbie Johnson

RSM, Mid Atlantic

Santiago Carol

RSM, Latin America

Steve Fleeman

RSM, Landing Gear

Contact Us

WSAA will be piloted at the East Alton, IL facility with the first round of apprentices anticipated to start in August 2024. For more information on West Star Aviation employment or WSAA apprentice selection criteria, please visit or contact Katie Johnson ( or Dave Lagermann (

Application & Selection Process

Before applying, please be aware of the standards of conduct for employment with West Star along with the strict requirements below while attending WSAA.

  • Working in Aviation requires a commit to being drug-free.  Pre-employment drug testing along with random and reasonable suspicion testing is required for all companies employing people working in safety sensitive positions. The position you are considering applying for is safety sensitive.  If hired, you must pass a DOT drug test to start working, if you fail the job offer is rescinded.  If you pass, you must remain drug-free during employment, failing a random or reasonable suspicion test may result in termination of employment.  Please note: marijuana is legal in certain states however the FAA follows Federal law where marijuana is illegal.  This means testing positive for marijuana, or any other illegal drug, will prevent you from working in Aviation. 
  • The first 7.5 months will follow a strict schedule: Monday – Friday 7:00am – 3:30pm (breaks and meal periods provided). 
  • The expectation is to arrive inside the learning center and clocked in at 7:00am.
  • While attending WSAA, no more than 4 hours a week can be missed.  Extenuating medical circumstances will be given full consideration with supporting documentation.
  • WSAA follows an FAA approved curriculum which has certain requirements including attendance. 
  • Testing for the FAA license at the conclusion of WSAA is required, along with passing.  Two opportunities to test will be provided, if needed.  Employment may terminate if the FAA license is not obtained.
  • Candidates will be contacted to complete pre-screening assessments and questionnaires. 
  • Qualified candidates will be contacted in late November and scheduled for a tour and interview with Hiring Managers at West Star Aviation in East Alton, IL.
  • To be qualified, candidates must pass the pre-screening process along with submitting a negative DOT drug test result.
  • Finalists will be selected after onsite interviews. Job offers will be extended in mid-December with a start date of January 9, 2024.
  • Pay while learning in the Academy will be $20 per hour.  Upon successfully graduating and obtaining your FAA license, pay will increase to $27 per hour.