Cold-Soak Synthetic APU Oil

AeroShell Turbine Oil 390 (ASTO 390) is a 3 mm²/s (cSt) synthetic diester turbine oil engineered with a specialized additive matrix for high thermal-oxidative stability and superior load-carrying capacity. Formulated specifically to overcome viscous drag during high-altitude cruising, ASTO 390 ensures rapid, reliable auxiliary power unit (APU) cold-soak starting in temperatures down to **-40°C**.

ETOPS & Aviation Maintenance Advantage: Fully qualified to British Specification DEF STAN 91-94 (Joint Service Designation OX-7), ASTO 390 maintains a significantly lower viscosity at extreme sub-zero temperatures (typically 2,000 cSt at -40°C versus 10,000 cSt for standard 5 cSt oils). This dramatically reduces hung-start risks on extended twin-engine operations (ETOPS) and holds active OEM approvals across Honeywell, Pratt & Whitney Canada, and Hamilton Sundstrand APUs.

Ordering Information:
• Packaging Unit: Individual 1 US Quart Can | MFG #: 550049742
• Please verify specific APU model compatibility and required case quantities with our aviation supply specialists before ordering.

Key Characteristics & Performance Benefits

• Optimized ETOPS Cold-Soak Starting: Lowers viscous drag under sub-zero in-flight shutdown conditions (-40°C), ensuring immediate APU startup during emergency electrical power demands.
• 3 cSt Synthetic Diester Chemistry: High-purity diester base matrix provides exceptional fluid circulation and thermal stability under severe flight envelopes.
• Extensive OEM Engine Approvals: Approved for Honeywell GTCP series, Hamilton Sundstrand APS series, and Pratt & Whitney Canada PW901A APUs.
• High Load-Carrying Capacity: Protects high-speed APU starter-generators, turbocompressors, and gearboxes against surface scoring and wear.
• Thermal-Oxidative Defense: Inhibits carbon varnish and sludge formation in high-temperature bearing chambers and oil galleries.

Typical Aviation Applications & Approved Engine Lines

• Honeywell APUs & Starters: Approved for GTCP 30, 36, 70, 85, 331, and 660 APUs, starters, and turbocompressors.
• Hamilton Sundstrand APUs: Fully qualified for APS 500, 1000, 2000, and 3000 series auxiliary power systems.
• Pratt & Whitney Canada APUs: Primary lubricant for PW901A APU equipment on commercial airliners.
• Turbomeca & Rolls-Royce Engines: Approved for Turbomeca (Astazou, Artouste, Makila) and Rolls-Royce (Conway, Spey, Tay, M45H) powerplants.

Technical Specifications & OEM Approvals

• All in-stock orders are processed within 1–2 business days (excluding weekends and holidays) after receiving your order confirmation email.
• Orders with a lead time will ship according to the estimated shipping time shown on the product page.
• If we experience a high volume of orders or if an item is backordered, processing times may be slightly delayed. We will notify you promptly via email.

• Returns and damage claims must be made within a maximum of 3 business days after receiving the product, with prior authorization from Aircraft Shop Supply (Return Material Authorization - RMA). Returns without prior notice or written authorization will not be accepted. We strongly recommend inspecting the product upon delivery; many products require special storage conditions for which we are not responsible once they arrive to the client's facility. Please review the product's SDS for proper storage and handling.
• For products with 3 to 6 months of remaining shelf life, claims must be made within the next 2 business days after receipt.
• Returns are not accepted for products with less than 3 months of remaining shelf life.
• Returns are not accepted for products purchased during a low Shelf Life promotion, items sold with discounts, or special orders that must be placed directly with the factory.
• The customer is responsible for the return shipping cost, except in cases where the return is due to an error on the part of Aircraft Shop Supply.
• Refunds will only be issued after the product has been inspected and no damage is found.
• A 25% Restocking Fee will be charged for returns of products in good condition that are either no longer needed or were ordered incorrectly.
• A 35% Restocking Fee will be charged for returns of products with one year or less of remaining shelf life.
• No Restocking Fee will be charged if Aircraft Shop Supply is responsible for incorrectly shipping a product, or if the order is damaged upon leaving the warehouse.
• Hazardous Materials & Dangerous Goods: These items are sold as final and are not eligible for return approval.

At Aircraft Shop Supply, we are committed to shipping the highest quality and freshest product possible. To ensure efficient stock rotation and meet aviation industry standards, our inventory management is governed by the following policy:

1. Scope of Application
All Sales Channels: This policy applies to all orders processed by Aircraft Shop Supply, including but not limited to: website purchases, direct email orders, formal Purchase Orders (POs), phone orders, and contract agreements.

2. Inventory Management (FIFO)
All products with an expiration date are managed and shipped on a strict "First In – First Out" (FIFO) basis.

3. Minimum Shipping Margin
Standard Guarantee: We will not ship any products with fewer than 30 days of use remaining (days before expiration), unless previously coordinated and agreed upon with the customer.

No Automatic Guarantees: Outside of this 30-day minimum margin, Aircraft Shop Supply does not make any automatic guarantee as to the specific length of time remaining on any shelf-life item for standard orders.

4. Special Customer Requirements
We understand that certain projects, maintenance schedules, or regulatory standards require strict specifications. If your order has specific shelf-life requirements, please proceed as follows:

How to Request: If you require a specific Date of Manufacture (DOM), Date of Expiration (DOE), or a specific minimum shelf-life percentage (%), you must clearly state this requirement:

In the Comments/Notes section when placing an online order.

Explicitly written on your Purchase Order (PO) or quote request email for offline orders.

Validation Process: Once your requirement is received:

We will ship your order if the available stock matches your specifications.

If we do not have the exact batch, we will contact you prior to shipping with the shelf-life percentage (%) or dates we have available for your acceptance.

5. Limitation of Liability and Validity of Information
To ensure transparency and manage expectations, the following terms and conditions apply:

Time-Limited Validity: Any information provided by our team regarding the remaining shelf-life percentage (%) is valid only at the exact time the inquiry is made. Due to high inventory turnover, availability is subject to change without prior notice.

Informational Purposes Only: Shelf-life data provided by Aircraft Shop Supply is strictly for informational purposes and reflects the availability at the moment of inquiry. It does not constitute a batch reservation or a product warranty.

Supply Chain Liability Exclusion: Aircraft Shop Supply is not responsible for the time elapsed or any product expiration that occurs after the order has been prepared and packed. This includes, but is not limited to: the time between order placement, carrier transit times, intermediary storage, customs delays, and final delivery to the end user. It is the customer's responsibility to account for these logistical lead times within their planning.