Senior Mechanical Engineer Amentum is a global leader in advanced engineering and innovative solutions, supporting critical missions across defense, intelligence, energy, and civilian sectors. Our people are our competitive advantage, driven by purpose, collaboration, and a commitment to delivering excellence for our customers and communities. We are currently seeking a Senior Mechanical Engineer to support our Projects. Description: As a senior-level mechanical engineer, you will serve as a technical leader responsible for the design, coordination, and delivery of building mechanical systems for industrial and government facilities. This role includes oversight of HVAC, plumbing, and piping system designs; leadership of mechanical engineering teams; and accountability for technical quality and compliance throughout the project lifecycle. The successful candidate will work closely with project management, discipline leads, and clients to deliver fully coordinated, code‑compliant, and high‑quality engineering solutions in accordance with Amentum’s established quality procedures. Key Responsibilities: Lead and oversee the design of HVAC, plumbing, and piping systems, including B31.3 process piping Serve as technical authority for mechanical system design within assigned project scope Review, approve, and check engineering calculations, layouts, specifications, and drawings Apply advanced engineering judgment to resolve complex design issues Support project planning by assisting with: Scope definition Equipment sizing Schedule development Budget control for mechanical design activities Coordinate mechanical designs with structural, electrical, architectural, and process disciplines Apply applicable codes, standards, and procedures (e.g., IMC, ASHRAE, NFPA, ASME) Interface with clients and other stakeholders as a senior technical contributor Provide senior‑level support during procurement and construction phases, including review and resolve RFIs, submittals, and field issues Mentor and guide engineers and designers on applicable codes, standards, and best practices Ensure all work under your technical responsibility complies with Amentum’s engineering and quality procedures Basic Qualifications: B.S. Mechanical Engineering from an ABET accredited engineering program 15+ years in industrial/government design of Mechanical, HVAC, Plumbing Systems, and related mechanical building systems Demonstrated experience delivering projects from concept through detailed design completion Proven ability to lead teams of engineers and designers within budget and schedule constraints Proficiency with discipline-specific tools such as: Carrier HAP, Trane TRACE, PipeFlo, AutoCAD, MicroStation, etc. Thorough knowledge of applicable codes & standards (International Mechanical Code, NFPA, ASHRAE, etc.) Professional Engineer (PE) license required Preferred Qualifications: In addition to the Basic Qualifications the ideal candidate might also have: Prior nuclear, DOE, or high‑hazard facility design experience Experience working under a formal quality program (ISO 9001, NQA 1) Strong leadership, communication, and technical mentoring skills Demonstrated attention to detail and commitment to technical excellence Proficiency with Microsoft Office (Excel, Word, Outlook) Work Environment: Primarily office-based work in a secure engineering environment  Amentum office location is preferred; hybrid or remote work may be available by prior agreement based on role and project requirements Occasional exposure to industrial facilities, which may include elevated noise levels, hazardous materials, or controlled areas Site visits may be required Physical Requirements:  Ability to sit or stand for extended periods Ability to lift up to 35 lbs occasionally Vision correctable to 20/20 Ability to read and use computer‑aided design software effectively Appropriate PPE and training will be provided as required Compliance & Eligibility Requirements: U.S. Citizenship required (no dual citizenship) Valid driver's license is required Ability to obtain and maintain a security clearance Ability to pass pre-employment background investigation and drug screening Willingness to work overtime or outside normal hours as needed Professional appearance appropriate for a customer‑facing engineering environment Travel required: less than 10% Compensation Details: $140,000 - $165,000 The compensation range or hourly rate listed for this position is provided as a good-faith estimate of what the company intends to offer for this role at the time this posting was issued. Actual compensation may vary based on factors such as job responsibilities, education, experience, skills, internal equity, market data, applicable collective bargaining agreements, and relevant laws. Benefits Overview: Our health and welfare benefits are designed to support you and your priorities. Offerings include: Health, dental, and vision insurance Paid time off and holidays Retirement benefits (including 401(k) matching) Educational reimbursement Parental leave Employee stock purchase plan Tax-saving options Disability and life insurance Pet insurance Note: Benefits may vary based on employment type, location, and applicable agreements. Positions governed by a Collective Bargaining Agreement (CBA), the McNamara-O'Hara Service Contract Act (SCA), or other employment contracts may include different provisions/benefits. Original Posting: 10/21/2026 - Until Filled Amentum anticipates this job requisition will remain open for at least three days, with a closing date no earlier than three days after the original posting. This timeline may change based on business needs. Amentum is proud to be an Equal Opportunity Employer. Our hiring practices provide equal opportunity for employment without regard to race, sex, sexual orientation, pregnancy (including pregnancy, childbirth, breastfeeding, or medical conditions related to pregnancy, childbirth, or breastfeeding), age, ancestry, United States military or veteran status, color, religion, creed, marital or domestic partner status, medical condition, genetic information, national origin, citizenship status, low-income status, or mental or physical disability so long as the essential functions of the job can be performed with or without reasonable accommodation, or any other protected category under federal, state, or local law. Learn more about your rights under Federal laws and supplemental language at Labor Laws Posters. Welcome back! We encourage you to check on the status of your current job applications with us. You can also search for a list of our current job openings and see if there are any new positions that might be a good fit for you. Thank you for continued interest in employment with Amentum. For more than 100 years, Amentum has tackled the world’s toughest challenges to deliver agile and steadfast solutions to the U.S. government and its allies. With more than 50,000 employees on all seven continents and in more than 60 countries, Amentum delivers a broad range of operational support services to meet the critical needs of our clients. Our headquarters are in Chantilly, VA. Find us online at https://www.amentum.com/ If you need a reasonable accommodation for any part of the employment process, please complete our Accommodation Request. Requests for accommodation will be considered on a case-by-case basis. If you need assistance, please reach out to workdaycandidateaccounts@amentum.com EEO including Disability/Protected Veterans Labor Laws Posters Amentum has become aware of unauthorized individuals who are falsely using the Amentum name and /or logo in an attempt to solicit fees from potential job seekers. These deceptive and unauthorized individuals are soliciting money, promising placement in a position with Amentum. Please note any communication requesting any amount of money in exchange for employment with Amentum is fraudulent. These communications do not originate from Amentum and are not associated with the recruitment process. Amentum and its affiliates never charge candidates fees or payments of any kind in order to secure employment. As a precaution, we recommend you do not disclose personal or financial details to anyone as a response to an unsolicited email, social media, or dating website request. Amentum will never as ask for a placement fee or any other fee to expedite the hiring process. If you are contacted by anyone offering employment with Amentum, you should never be asked to pay a fee for recruiting. Amentum personnel will always send email from an identifiable corporate account (ending in @amentum.com) and never from a public email account like Yahoo!, Google, Gmail, or Hotmail. If you are contacted regarding a fraudulent employment proposal, we encourage you to alert your local law enforcement agency/police authority. To read more about Amentum’s commitment to ethics, please click here.

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