PPG PR1422 vs. PR1440 vs. P/S 890: Which Aircraft Fuel Tank Sealant Should You Use?

Choosing the correct aircraft fuel tank sealant isn't always straightforward. Three of the most common products specified throughout the aerospace industry are PPG PR1422, PPG PR1440, and PPG P/S 890. At first glance, they appear nearly identical—they're all two-part polysulfide sealants designed for integral fuel tanks, they're all available in multiple application classes and work lives, and they all provide excellent resistance to aviation fuels.

So why are there three different products, and when should each one be used?

This guide explains the differences between these sealants, their specifications, and how to select the correct product for your aircraft maintenance application.

Quick Comparison

What Is PR1422?

PPG PR1422 has been one of the aerospace industry's most widely specified fuel tank sealants for decades. It is qualified to AMS-S-8802 Type I and is designed for sealing integral fuel tanks, access panels, fasteners, rivets, and fay surfaces.

Many legacy military, commercial, and general aviation aircraft maintenance manuals specifically reference PR1422 or require a Type I sealant. Because of its long qualification history, it continues to be widely used throughout North America.

What Is PR1440?

PR1440 was developed as a Type II fuel tank sealant meeting the same AMS-S-8802 performance specification but using a different curing chemistry.

Rather than replacing PR1422, PPG introduced PR1440 as a separately qualified product. This allowed aircraft manufacturers and maintenance organizations to specify either Type I or Type II based on their engineering requirements and approved maintenance data.

In Europe, PR1440 also became the preferred replacement for many Type I applications because of changing environmental regulations affecting certain raw materials used in Type I formulations.

What Is P/S 890?

P/S 890 is another PPG two-part polysulfide fuel tank sealant qualified to AMS-S-8802 Type II.

Although it meets the same specification and serves the same primary purpose as PR1440, it belongs to PPG's P/S product family rather than the legacy PR series.

From a maintenance standpoint, P/S 890 is commonly used for:

• Integral fuel tanks

• Fillet sealing

• Fay surface sealing

• Fastener sealing

• Fuel-tight structural joints

Its published performance characteristics are very similar to PR1440.

Are PR1440 and P/S 890 the Same Product?

Not exactly.

Both products:

• Meet AMS-S-8802 Type II

• Use manganese dioxide curing chemistry

• Are available in Class A, B, and C

• Offer multiple work-life options

• Resist aviation fuels, oils, and hydraulic fluids

• Remain flexible after curing

However, they are separate qualified products with different formulations, manufacturing histories, and qualification records. Aircraft maintenance personnel should always follow the aircraft manufacturer's approved maintenance data when selecting a sealant.

Can You Substitute One for Another?

That depends on the aircraft documentation.

If an Aircraft Maintenance Manual specifies:

• PPG PR1422, use PR1422 or an approved equivalent.

• AMS-S-8802 Type I, use a qualified Type I sealant.

• AMS-S-8802 Type II, use a qualified Type II sealant such as PR1440 or P/S 890.

• AMS-S-8802 without specifying a type, verify the required qualification using the OEM maintenance documentation before selecting a replacement.

Never assume two sealants are interchangeable simply because they are both polysulfide fuel tank sealants.

Understanding the Product Numbers

Aircraft sealant designations contain useful information.

For example:

PR1422B2

• PR1422 – Product family

• B – Class B (extrudable)

• 2 – Approximately 2-hour work life

The same convention applies to PR1440 and P/S 890 products.

Which Sealant Is Best?

There isn't a universally "best" product.

The correct sealant is the one specified by the aircraft manufacturer or approved engineering documentation.

Choose:

• PR1422 when a Type I sealant is required.

• PR1440 when a Type II PR-series sealant is specified.

• P/S 890 when it is listed in the maintenance documentation or approved as an equivalent Type II sealant.

For maintenance organizations, regulatory compliance and adherence to approved data are always more important than selecting a sealant based solely on brand or product family.

Final Thoughts

Although PR1422, PR1440, and P/S 890 share many performance characteristics, understanding the differences between Type I and Type II qualifications helps ensure the correct product is selected for each maintenance task.

Before ordering a replacement sealant, always review the Aircraft Maintenance Manual (AMM), Structural Repair Manual (SRM), engineering drawings, or other approved maintenance documentation to verify the required specification, application class, and work life.

Selecting the proper sealant helps maintain fuel system integrity, supports corrosion protection, and ensures compliance with OEM and regulatory requirements.