Suction Relief Valve

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Pressure Regulator and Relief Valve

Aircrew Survival Equipmentman 2

Deice and Anti-Icing Systems for the S-3 Aircraft

SUCTION RELIEF VALVE.- The suction relief valve installed in the suction manifold lines leading from the ejector to the tail section distributor valve regulates deice system suction. When suction in the manifold lines becomes excessive, the spring tension that seats the relief valve is overcome, and the valve opens to permit compartment air into the suction manifold lines until the suction pressure is reduced to approximately 6 in. Hg. An adjusting nut on the relief valve is used to adjust the tension on the spring that seats the relief valve. "On aircraft" adjustment is generally prohibited.

DEICE BOOTS.- The rubber deice boots (fig. 1-7) are attached to the leading edge surfaces with cement or fairing strips and screws, or a combination of both. On the E-2A, they are bonded to the leading edges with cement and tapered slightly to provide a smooth airflow over the boot and wing, when the boots are deflated.

PRESSURE GAGE.- The deice system cockpit-mounted pressure gage indicates the pressure available for inflating the deice boots when the system is operating. The gage is calibrated from 0 to 20 psi in 1 psi increments. Normal system operation is indicated by a slight pressure fluctuation of the pointer. This fluctua-tion is caused by a momentary drop in pressure at the beginning of each inflation period for each deice boot group. A steady reading of 18 psi on the gage indicates a nonoperating condition.

SUCTION GAGE.- The deice system cock-pit-mounted suction gage indicates the suction available for deflating the deice boots. The 0 to 10 in. Hg gage is calibrated in major increments of 1 in. Hg and minor increments of 0.2 in. Hg. Slight pointer fluctuation indicates proper system operation, as was the case with the pressure gage. A steady reading of 6 in. Hg on the gage indicates a nonoperating condition.

Deice Boot System Maintenance

Maintenance of deice boot systems is normally performed by personnel of the AE, AME, and AMS ratings. Personnel of the AMS rating are primarily concerned with the removal, installation, and miscellaneous repairs of the deice boots. AE personnel are concerned with removal, replacement, and repair of deice system electrical components. The AME is generally responsible for all other components of the deice system. AME personnel assigned to the organizational level of maintenance are responsible for removal and replacement of malfunctioning components, maintenance of associated plumbing, and render-ing of assistance to senior personnel in the performance of operational checkouts and troubleshooting. Some steps of the operational check, as out-lined in the applicable MIM, are performed using external electrical power and an external air supply. The air supply is connected to the bleed-air line test connection and must be capable of supplying a pressure of 50 to 90 psi. Remaining steps of the operational checkout require that one of the aircraft's engines be started.

NOTE: Personnel turning up naval aircraft must be fully qualified, designated in writing, and carry a current turnup card in accordance with OPNAV 4790.2.

All steps of the operational checkout must be performed in the sequence outlined in the MIM. When a malfunction occurs during a step, it must be corrected before proceeding to the next step. Troubleshooting, removal and replacement of components, and the operational checkout should always be accomplished in accordance with the specific instructions provided in the applicable MIM with appropriate emphasis on quality workmanship and inspection.