FDC aerofilter 1500 Series

Questions and Answers

F
fwashingtonAug 4, 2025
What to do if annunciator light is on at high power with known clean filter element installed in FDC aerofilter 1500?
- G
  Garrett MartinAug 5, 2025
  If the annunciator light is on at high power even with a clean filter element installed in your FDC Water Filtration System, this could indicate turbine section degradation or an out-of-limits DPS. Perform an engine power check and conduct a functional test of the DPS.
B
Brianna WilsonAug 10, 2025
Why is the annunciator light on at all power settings in FDC aerofilter 1500?
- B
  Barbara OrtizAug 11, 2025
  The annunciator light might be on at all power settings in your FDC Water Filtration System because the filter element is dirty. In a harsh environment, select ALT AIR to OPEN only if the TOT for required power exceeds limits. Select ALT AIR to OPEN when in clean air. Remember to clean the filter element before the next mission.
T
Theresa SmithAug 16, 2025
What to do if annunciator light stays on when ALT AIR switch is set to OPEN in FDC aerofilter 1500 Water Filtration Systems?
- B
  Beth KerrAug 17, 2025
  If the annunciator light stays on when the ALT AIR switch is set to OPEN in your FDC Water Filtration System, the actuator may have failed in the retracted position. You should replace the actuator.
J
jorgerowlandAug 23, 2025
Why does annunciator flicker at all power settings in FDC aerofilter 1500 Water Filtration Systems?
- C
  Crystal VaughnAug 23, 2025
  If the annunciator light “flickers” at all power settings in your FDC Water Filtration System, it might be because the filter element is partially clogged. Monitor engine instruments and avoid selecting ALT AIR to OPEN if the TOT is within limits.
K
Kimberly FergusonAug 28, 2025
How to fix annunciator light on when engine is not running in FDC aerofilter 1500 Water Filtration Systems?
- B
  Brandi BergerAug 29, 2025
  If the annunciator light is on when the engine is not running on your FDC Water Filtration System, it is likely that the DPS is stuck in the closed position. Replace the DPS to resolve this issue.

Summary

Introduction to Engine Inlet Barrier Filter System

General Product Information

Details the engine filter system's design for turbine engine protection against foreign object damage and micro erosion.

Scope of ICA

Outlines the manual's content covering airworthiness limitations, service instructions, inspection, and testing procedures.

Precautions for Maintenance

Defines warning, caution, and note indicators used in maintenance procedures to ensure safety and equipment integrity.

Definitions and Abbreviations

Lists and defines terms, abbreviations, acronyms, and symbols used throughout the manual for clarity.

Document Distribution and Updates

Explains the process for obtaining revisions and updates to the ICA and the user's responsibility to maintain the latest version.

Inspection and Test Requirements

General Information on Inspections

Covers basic maintenance and service requirements for safe operation and continued airworthiness of the filter system.

Service Intervals for Inspections

Specifies recommended service intervals for various inspection requirements based on flight hours and conditions.

Filter Element Servicing Procedures

General Information on Servicing

Provides guidance on handling the filter element with care to prevent damage during servicing operations.

Filter Element Removal and Reinstallation

Details the step-by-step procedure for safely removing and reinstalling the filter element from the aircraft.

Filter Element Cleaning Methods

Describes the approved methods and cleaning agents for cleaning the filter element under normal and severe conditions.

Element Inspection (Severe Conditions)

Specifies detailed inspection criteria for filter elements used in severe environmental conditions.

Element Inspection (Normal Conditions)

Outlines inspection procedures and service life limits for filter elements under normal operating conditions.

Filter Element Oiling Procedure

Provides instructions for applying the correct oil to the filter element to ensure proper tack barrier formation.

Component Replacement Procedures

Actuator Removal and Replacement

Details the steps for removing and reinstalling the actuator assembly, including connection and verification.

DPS Removal and Replacement

Provides instructions for the removal and replacement of the Differential Pressure Switch (DPS) assembly.

Functional Test Procedures

DPS Functional Test

Details the procedure for testing the Differential Pressure Switch (DPS) and its associated annunciator.

The document describes the FDC/aerofilter™ ICA 1500-SERIES-ICA-1 Instructions for Continued Airworthiness for the 1500EFS Engine Inlet Barrier Filter System installed on MDHI/Hughes OH-6 A-C “CAYUSE” helicopters.

Function Description

The 1500EFS Engine Inlet Barrier Filter System is designed to protect the turbine engine from foreign object damage (FOD) and micro-erosion, particularly when operating in normal and severe environmental conditions. It achieves this by filtering airborne dust particles before they enter the engine.

The system comprises:

Duct Assembly: The main structure housing the filter element.
Alternate Air Door Assembly: A pilot-actuated system that bypasses the filter elements in case of filter blockage or degraded engine performance.
Filter Element: The core filtration component.
Low Inlet Pressure Annunciator System (DPS): A warning system that alerts the pilot to low inlet pressure, typically indicating a clogged filter.

The filter element itself is made of a specially formulated polymerized oil suspended by a pleated wire cloth and cotton fabric matrix. This design allows it to attract and hold airborne dust particles effectively.

Important Technical Specifications

While specific numerical technical specifications are limited in the provided excerpts, the document highlights several critical operational and performance aspects:

Filtration Medium: Polymerized oil suspended by pleated wire cloth and cotton fabric matrix.
Filter Element Servicing: Cleaned and re-oiled at regular intervals or as required.
Alternate Air System: Pilot-actuated bypass for filter blockage.
Low Inlet Pressure Annunciator (DPS): Activates at 9 inches H2O (±1 inch H2O) differential pressure, indicating a need for filter servicing or alternate air activation.
Filter Element Life: Elements should be replaced after 1500 hours in service, though this can be extended with FDC Engineering approval.
Filter Oil: FDC/aerofilter Oil, P/N 40–10 or PN 40–10CW, is a compounded mineral-based blend with special polymers and a blue dye for application visibility.

Usage Features

The system is designed for use in various environmental conditions, with particular emphasis on protecting the engine in dusty or severe environments.

Pilot Actuated Alternate Air: Allows the pilot to bypass the filter elements if engine performance degrades due to filter blockage, ensuring continued engine operation.
Low Inlet Pressure Annunciator: Provides a crucial warning to the pilot when the filter is becoming restricted, prompting timely action (e.g., activating alternate air or planning for filter servicing).
Visual Inspection: Operators are encouraged to visually inspect the filter through the inlet fairing before each flight to remove large debris and assess the filter's condition.
Responsibility for Increased Frequency: The operator is responsible for increasing inspection frequency and scope under severe or unusual environmental conditions or as flight requirements dictate.

Maintenance Features

The document provides detailed instructions for the continued airworthiness of the 1500EFS system, focusing heavily on maintenance and servicing.

General Maintenance Philosophy:

Careful Handling: Emphasizes extreme care when handling the filter element during servicing to prevent damage to the fragile wire mesh and pleated material.
Qualified Personnel: All inspections and maintenance must be performed by qualified personnel in accordance with standard aircraft practice.
Compliance: Adherence to all applicable Service Bulletins and Airworthiness Directives is mandatory.

Service Intervals (Table 3.1):

Each Flight: Visual Inspection of Installed Filter Element (remove debris, note condition of element and screens).
100 ± 10 HR Interval: Inspect, Clean, and Re-Oil Filter Element; Inspect and Cycle Alternate Air Door; Inspect and Cycle Differential Pressure Switch / Warning Annunciator components; Inspect Electrical Connections; Inspect Attachment Hardware, Mounting Brackets; Inspect Housing Structure and Dust Boot for Wear & Cracks.
300 ± 10 HR Interval: Inspect, Clean, and Re-Oil Filter Element (if not done at 100 HR); Inspect and Cycle Alternate Air Door (if not done at 100 HR); Inspect and Cycle Differential Pressure Switch / Warning Annunciator components (if not done at 100 HR); Inspect Electrical Connections (if not done at 100 HR); Inspect Attachment Hardware, Mounting Brackets (if not done at 100 HR); Inspect Housing Structure and Dust Boot for Wear & Cracks (if not done at 100 HR).
Annual Interval: Leak and Pressure Test Differential Pressure Switch.

Filter Element Servicing (Section 4.0):

Removal/Reinstallation: Detailed steps for removing and reinstalling the filter element, including loosening fasteners, lifting the front edge, and inspecting housing seals.
Cleaning:
- Tapping: Gently tap the clean side up to dislodge large debris.
- Approved Cleaner: Use only FDC/aerofilter cleaner (P/N 40-15). Strict warnings against using gasoline, jet A/kerosene, caustic solutions, detergents, parts cleaning solvents, pressure/steam cleaners, or high-pressure hose nozzles.
- Severe Conditions Cleaning: Soak dirty side down for 20-60 minutes, shake, then re-soak for 5 minutes in clean cleaner.
- Normal Conditions Cleaning: Spray liberally or soak in a shallow pan for 10 minutes.
- Rinsing: Rinse with low-pressure water from the clean side to the dirty side.
- Drying: Shake off excess water and allow to dry naturally, including in direct sunlight. Strict warnings against using compressed air, open flame, hair dryers, or heat guns due to risk of media shrinkage and damage.
Inspection (Severe Conditions):
- Inspect fine mesh on the forward surface for erosion (rejection if > 0.50 in.).
- Inspect coarse mesh on the aft surface for wire wear, breakage, or deterioration (cause for rejection).
- After cleaning and before re-oiling, check for holes > 0.020 in. (normal pinholes are acceptable if oiled). Holes > 0.030 in. are cause for rejection.
- Check frames, aft element latch brackets, and forward element Camloc receptacles for security and loose rivets. Rectify defects or consult FDC Engineering.
- Recommendation to have a spare pre-oiled element for severe conditions.
Inspection (Normal Conditions):
- At 100 ± 10 hours or upon DPS activation, remove and inspect per severe conditions guidelines.
- Elements replaced after 1500 hours, or extended with FDC Engineering approval.
Oiling:
- Approved Oil: Use only FDC/aerofilter Oil, P/N 40–10 or PN 40–10CW. Warnings against engine oil, transmission oil, hydraulic fluid, or lightweight oils (WD-40, LPS, etc.).
- Application: Fill sprayer with 15 fluid ounces of oil, charge with compressed air. Apply with smooth, complete passes parallel to pleats, then 90 degrees to pleats. Use all measured oil.
- Wicking: Wait 30 minutes for proper wicking, then lightly re-oil any light areas. Do not over-oil.

Component Replacement (Section 5.0):

Actuator Removal/Replacement: Detailed steps for removing and reinstalling the actuator, including disconnecting harness, removing housing sections, and securing with specific fasteners (finger tight for cotter pin, tight for lock nut).
DPS Removal/Replacement: Detailed steps for removing and reinstalling the Differential Pressure Switch, including disconnecting harness and pressure line, and removing mounting screws.

Functional Test (Section 6.0):

DPS Functional Test:
- Connect battery, turn on master switch.
- Connect vacuum tester to DPS pressure port.
- Apply suction to check annunciator light activation at 9 ± 1 in. H2O. Replace DPS if out of limits.
- Remove test equipment, replace pressure tube.
- Lift guard, put ALT AIR switch to OPEN, check bypass door actuation to full open.
- Put ALT AIR switch to CLOSED, check bypass door actuation to fully closed and secure.

Troubleshooting (Section 7.0):

A table outlining common symptoms (e.g., annunciator light on/flickering, alternate air not opening), probable causes (e.g., DPS stuck, clogged filter, actuator failure, turbine degradation), and corresponding actions (e.g., replace DPS, clean filter, replace actuator, engine power check).

The document is a comprehensive guide for maintaining the airworthiness and optimal performance of the 1500EFS Engine Inlet Barrier Filter System, ensuring engine protection and operational safety.