Hawker 800XP Hydraulic Relief and Non-Return Valve Identification

Start with valve function, not the word valve

The ATA 29 export uses valve descriptions that are short enough to create false matches. Relief, pressure release, reducing, pressure maintaining, and non-return are different roles. Even within the non-return group, the part numbers sit at different positions and use different relationship language.

The fastest clean lookup is:

1. Read the complete data-plate number and dash number.
2. Identify the hydraulic function and aircraft location.
3. Match the IPC figure, item, quantity, and effectivity.
4. Read replacement or alternate wording exactly as printed.
5. Verify the offered unit against current approved data.

Relief and pressure-control valve map

Function	Part number or family	Figure and item	Printed relationship
Full-flow relief	AIR45394, AIR45394-0	29-10-05-25 item 195	Base points to -0; quantity 2
Pressure release	AC69536	29-10-05-25 items 465, 475, 480	Same number at three positions; SB29-3225
Pressure maintaining or monitoring	AIR45474, AIR45474-0	29-10-05-25 item 330 and 29-10-05-50 item 51	Base points to -0; source uses two names
Inward relief	AIR45418, AIR45418-0	29-10-05-40 item 235	Base points to -0; -0 is exchange item
Outward reservoir relief	AIR87236	29-10-05-30 item 240	Base points to AIR87236-0; no separate -0 application row supplied
Mark 3 reducing	AC61518	29-10-05-50 item 530	Unit exchange; no replacement printed
Reducing or pressure regulator	PAS129-163	29-10-05-40 item 205	No replacement printed

The terms inward and outward matter on AIR45418 and AIR87236. Treating both as hydraulic relief valve without the position can send the wrong family into the quote.

AIR45394 and AIR45394-0

The base AIR45394 row tells the reader to order AIR45394-0 for spares. Both numbers occupy item 195 with quantity 2 and effectivity 8266-8999. The family references CMM 29-10-1102.

That is a forward replacement. It does not say that every AIR45394-0 condition or overhaul status is acceptable, and it does not authorize a reverse substitution.

AIR45418 and the excluded serials

AIR45418 points to AIR45418-0. Both rows exclude serials 8401, 8421, 8434, and 8447. The -0 row is also marked as a unit exchange item.

When one of those four aircraft is involved, do not stretch the surrounding serial range across the gap. Resolve that aircraft in current approved data.

AIR45474 has two names in the IPC

The source calls AIR45474 a pressure-maintaining valve in one figure and a pressure-monitoring valve in another. Both rows point to AIR45474-0, use quantity 1, carry effectivity 8266-8999, and reference CMM 29-10-1123.

The matching number and relationship support one family record. The conflicting names should remain visible instead of choosing one without additional technical data.

Non-return valve map

Part number or family	Catalog position	Key caution
AIR87240	LH and RH engine hydraulic-pump figures	No -0 replacement is printed in the supplied rows
AIR45468, AIR45468-0	29-10-05-25 item 280	Base points to -0
25-7SF281A, AIR87246	29-10-05-20A item 30	Reciprocal alternate-spare pair
HTE400096	29-10-05-20A item 575	Stand-alone line non-return valve record
HTE4350	29-10-05-40 item 90	Quantity 2, four serial exclusions, and same number appears in fuel records
HTE4853	29-10-05-30 item 200	Quantity 1 in the tank figure; not printed as an HTE4350 alternate
AIR48026, AIR48026-0	Repeated ATA 29 and ATA 32 positions	Base points to -0 across several rows

Non-return valve is a function class, not an interchange statement.

25-7SF281A and AIR87246 are a real reciprocal pair

The 25-7SF281A row lists AIR87246 as an alternate spare. The AIR87246 row lists 25-7SF281A as an alternate spare. Both are at Figure 29-10-05-20A item 30 with quantity 1, effectivity 8266-8999, and CMM 29-10-1142.

This is stronger than a one-way replacement because the relationship is printed in both rows. It still does not establish the condition or release status of an offered valve.

HTE4350 is a cross-system search trap

The hydraulic row for HTE4350 calls for quantity 2 in Figure 29-10-05-40. Separate Hawker records also use HTE4350 in ATA 28 fuel positions. Supplier listings may therefore use bleed-air, high-temperature-flow, fuel, or general non-return descriptions.

Do not resolve this number from the supplier title alone. Send the hydraulic system, figure 29-10-05-40, item 90, and intended tank-pressure function with the request.

What the valve pages can and cannot answer

The records can answer the printed part identity, catalog location, quantity, effectivity, CMM reference, and replacement or alternate wording. They cannot provide cracking pressure, relief setting, flow direction, bench-test limits, overhaul status, or installation approval.

Those decisions require the applicable current CMM, aircraft maintenance data, modification status, and the offered unit’s release paperwork.