Aviation fuel (Jet A-1) depot and into-plane release controls: tank settling clocks, filter-water-separator differential pressure, and water-detector signoffs

Topics: aviation fuel depot quality release software, petroleum distribution software, bulk fuel inventory management.

Unlike retail automotive fuel stations (O028) where trace moisture or particulate haze rarely causes immediate catastrophic engine failure, aviation turbine fuel (Jet A-1 / ATF) transferred into commercial aircraft wings at $-47^\circ\text{C}$ freeze-point specification must be virtually free of suspended water ($<15\text{ ppm}$) and particulate matter ($<0.2\text{ mg/L}$). Frozen free water in wing surge tanks can block fuel boost pumps or ice fuel-oil heat exchangers at cruising altitude. This guide (O117) defines the JIG 1 / JIG 2 aligned ERP, TAS (Terminal Automation System), and into-plane fuelling quality-release architecture.

Scope and governance boundary

This article specifies the operational and quality-control record architecture from airport fuel-depot receipt to aircraft wing coupling:

• What this workflow governs: Receipt batch genealogy (Refinery CoQ $\rightarrow$ Release Certificate), PLC/TAS tank isolation and settling timers, daily low-point sump drain visual/chemical water logs, floating-suction arm check records, flow-normalized FWS differential-pressure ($\Delta P$) graphing, Millipore colorimetric/gravimetric filtration checks, and into-plane uplift release interlocks.
• What this workflow does not replace: It does not replace licensed aviation fuel laboratory testing under ASTM D1655 / Def Stan 91-091, physical deadman handle and hydrant pit-valve emergency shutoff hardware, or aircraft captain fuel-load calculation authority.

1. Step 1 — Record intake & baseline identification: Enforce hard state-machine locks on Airport Fuel Farm storage tanks (`Receiving` $\rightarrow$ `Isolated Settling` $\rightarrow$ `Sump Sampled & Recertified` $\rightarrow$ `Released to Hydrant`) so no tank outlet motorized valve can open into the hydrant ring main while a post-receipt settling clock is still running ([JIG 2](https://www.jig.org/publications/)).
2. Step 2 — Cross-system reference & custody linkage: Verify batch homogeneity before releasing a settled tank: compare top/middle/bottom laboratory density at $15^\circ\text{C}$ against the upstream Refinery Certificate of Quality (CoQ) or Release Certificate (RC), blocking release if density variance exceeds **$\pm 3.0\text{ kg/m}^3$** ([ASTM D1655](https://www.astm.org/d1655-22a.html)).
3. Step 3 — Exception quarantine & authority check: Normalize into-plane hydrant dispenser and refueller **Filter Water Separator (FWS)** differential pressure ($\Delta P$) to maximum rated flow ($\Delta P_{\text{corr}} = \Delta P_{\text{obs}} \times (Q_{\text{max}}/Q_{\text{obs}})^2$) so partially plugged coalescer elements or collapsed cartridges are caught even during low-flow narrow-body aircraft refuellings ([EI 1581](https://publishing.energyinst.org/) / [JIG 1](https://www.jig.org/publications/)).
4. Step 4 — Verified disposition & audit trail closure: Require every aircraft uplift ticket to link a passing chemical free-water detector check ($<15\text{ ppm}$ warning / $<30\text{ ppm}$ stop), electrical conductivity check ($50\text{–}600\text{ pS/m}$), and daily floating-suction buoyancy check to the batch genealogical chain.

Why manual paper clipboards miss latent aviation fuel quality escapes?

Airport fuel depots and into-plane service providers that rely on unvalidated paper logs face three systemic failure modes:

1. Premature Tank Valve Opening During Settling: When peak morning flight bank demand drains the active service tank, operators under time pressure may open a freshly filled tank before completing the JIG 2 minimum settling period ($2\text{ hours}$ after microfiltered pipeline/bridger receipt, or $1\text{ hour per metre}$ of fuel depth when microfiltration is absent) or before verifying that density stratification ($>3.0\text{ kg/m}^3$) is absent.
2. Unnormalized Filter Water Separator (FWS) Differential Pressure ($\Delta P$): An into-plane hydrant dispenser rated at $Q_{\text{max}} = 3,800\text{ L/min}$ refuelling an Airbus A320 through a single underwing hose at $Q_{\text{obs}} = 1,400\text{ L/min}$ will show a raw gauge $\Delta P$ of only $0.20\text{ bar}$ ($2.9\text{ psi}$) even when coalescer elements are approaching the $1.38\text{ bar}$ ($20.0\text{ psi}$) rated-flow plug limit. Conversely, a sudden drop in normalized $\Delta P$ indicates a ruptured coalescer sock allowing unfiltered fuel bypass.
3. Unlinked Chemical Water-Detector and Conductivity Drift: Static dissipator additive (Stadis 450) depletes across clay treaters and pipelines. If tank conductivity drops below $50\text{ pS/m}$ at the hydrant header, high-velocity into-plane filtration generates dangerous electrostatic charge accumulation inside aircraft wing tanks.

• Primary control scope: aviation fuel depot quality release software across operations and connected ERP/EAM records.
• Segregation boundary: Operational status updates never auto-close engineering, safety, or finance sign-off gates.
• Verification cadence: Reconcile open exceptions, overrides, and late adjustments at each shift or period close.

JIG-aligned aviation fuel depot and into-plane control matrix

Illustrative worked example: airport depot tank release and hydrant dispenser FWS $\Delta P$ normalization

Illustrative operating scenario with synthetic figures to demonstrate aviation quality-release and flow-normalized differential-pressure arithmetic; not a client case study or airworthiness release.

Consider an international airport fuel depot managing vertical epoxy-lined storage tank TK-JET-03 ($4,000\text{ m}^3$ capacity) and into-plane hydrant dispenser HD-14 (rated maximum flow $Q_{\text{max}} = 3,800\text{ L/min}$).

Step 1: Verify TK-JET-03 settling clock and batch density homogeneity

1. Receipt and settling window:
   • Pipeline batch PL-J1-1020 delivers $3,200\text{ m}^3$ of Jet A-1 through a $5,\mu\text{m}$ microfilter into TK-JET-03 ($12.0\text{ m}$ liquid height), closing inlet valve MOV-IN-03 at 04:00.
   • Under JIG 2, microfiltered pipeline receipts require at least $2.0\text{ hours}$ of undisturbed isolation settling before bottom sump flushing and sampling. The TAS holds outlet valve MOV-OUT-03 electrically locked until 07:30 ($3.5\text{ hours}$ elapsed $> 2.0\text{ hours}$ minimum).
2. Batch density recertification at $15^\circ\text{C}$ (ASTM D1655):
   • Upstream Refinery Release Certificate (RC-8841) density @ $15^\circ\text{C}$: $798.4\text{ kg/m}^3$
   • TK-JET-03 heel before receipt ($420\text{ m}^3$): $801.1\text{ kg/m}^3$
   • Expected blended tank density @ $15^\circ\text{C}$: $$\rho_{\text{expected}} = \frac{(3,200 \times 798.4) + (420 \times 801.1)}{3,620} = \frac{2,554,880 + 336,462}{3,620} = 798.71\text{ kg/m}^3$$
   • Laboratory digital densitometer reading on TK-JET-03 floating-suction composite sample: $799.6\text{ kg/m}^3$.
   • Variance vs upstream certificate: $$\Delta\rho_{\text{cert}} = 799.6\text{ kg/m}^3 - 798.4\text{ kg/m}^3 = +1.2\text{ kg/m}^3\quad (\text{within }\pm 3.0\text{ kg/m}^3\text{ JIG/ASTM limit})$$
   • Variance vs expected blend calculation: $+0.89\text{ kg/m}^3$ (within $\pm 1.0\text{ kg/m}^3$ tank stratification limit); electrical conductivity $= 185\text{ pS/m}$ (within $50\text{–}600\text{ pS/m}$); chemical water detector $= 4\text{ ppm}$ ($<15\text{ ppm}$). TK-JET-03 is issued release token REL-TK03-20261020.

Step 2: Evaluate hydrant dispenser HD-14 normalized FWS differential pressure during wide-body uplift

Dispenser HD-14 connects to hydrant pit PIT-B12 (fed by TK-JET-03) to uplift $82,000\text{ L}$ into a long-haul wide-body aircraft at an actual pumping rate of $Q_{\text{obs}} = 2,660\text{ L/min}$ ($70.0%$ of the vessel's $Q_{\text{max}} = 3,800\text{ L/min}$ rated design flow).

• Why flow normalization mattered: Looking only at the raw gauge ($0.68\text{ bar} / 9.86\text{ psi}$), an operator on a paper clipboard would pass HD-14. By applying the quadratic flow correction (JIG 1): $$\Delta P_{\text{corr}} = \Delta P_{\text{obs}} \times \left(\frac{Q_{\text{max}}}{Q_{\text{obs}}}\right)^2 = 0.68\text{ bar} \times \left(\frac{3,800}{2,660}\right)^2 = 0.68\text{ bar} \times 2.0408 = 1.39\text{ bar}\quad (20.16\text{ psi})$$ the ERP/telemetry module detects that HD-14's coalescer cartridges have crossed the $1.38\text{ bar}$ ($20.0\text{ psi}$) change-out ceiling at rated flow. Because nozzle water ($8\text{ ppm}$) and Millipore (B1) are clean, the current uplift closes normally, and the fleet dispatch system automatically places HD-14 in Maintenance Lockout (STATUS: FWS_ELEMENT_CHANGE_DUE) so it cannot be assigned to another flight until fresh EI 1581 coalescer elements are installed.

Acceptance tests and operational readiness criteria

1. ACT-O117-01 (Hard PLC/TAS Tank Settling Timer Lock): When a depot storage tank receives fuel (MOV-IN open), the TAS/ERP integration must immediately transition the tank to Isolated Settling, hold MOV-OUT closed, and prevent release token generation until the minimum settling duration ($2\text{ hours}$ microfiltered or $1\text{ hour/m}$) and a passing sump-drain record are logged.
2. ACT-O117-02 (Density @ $15^\circ\text{C}$ & Conductivity Recertification Gate): If the recertification laboratory density @ $15^\circ\text{C}$ differs from the upstream Refinery CoQ/RC by more than $\pm 3.0\text{ kg/m}^3$ (or if electrical conductivity falls outside $50\text{–}600\text{ pS/m}$), the system must block batch release.
3. ACT-O117-03 (Quadratic Flow-Normalized FWS $\Delta P$ Calculation): For every into-plane uplift, the vehicle telemetry/ERP log must compute $\Delta P_{\text{corr}} = \Delta P_{\text{obs}} \times (Q_{\text{max}}/Q_{\text{obs}})^2$ and lock the dispenser/refueller for element change-out whenever $\Delta P_{\text{corr}} > 1.38\text{ bar}$ ($20.0\text{ psi}$) or when $\Delta P_{\text{corr}}$ drops by $>0.25\text{ bar}$ from the prior uplift.
4. ACT-O117-04 (Wing-Nozzle Water Detector & Batch Genealogy Trace): Every electronic uplift ticket must record the active depot tank release token (REL-TK03-...), vehicle ID, and passing chemical water detector reading ($<15\text{ ppm}$) before invoice/uplift sign-off.

Next steps

1. Hardwire TAS motorized outlet valves (MOV-OUT) to ERP quality release tokens: Eliminate the possibility of manual valve opening before tank settling clocks and lab recertifications clear.
2. Automate quadratic $\Delta P$ flow normalization in into-plane tablet software: Replace manual graph look-up charts with real-time $\Delta P_{\text{corr}}$ calculation on every refuelling run.
3. Log daily floating-suction buoyancy checks and low-point sump flushes as mandatory shift pre-requisites: Catch sunken suction cables before bottom water reaches the hydrant pump header.
4. Maintain full refinery-to-wing batch genealogy on every aircraft fuel ticket: Link each flight uplift back to the exact depot tank release certificate and refinery batch number.

Frequently Asked Questions

How should aviation turbine fuel (ATF / Jet A-1) depot and into-plane operators enforce tank settling times, floating-suction checks, filter-water-separator differential pressure, and chemical water-detector batch release?

Teams should govern aviation fuel depot quality release software by linking every transaction to its source evidence, timestamp, and assigned owner before permitting downstream posting. Distinct from O028 (retail fuel station wet-stock reconciliation); O117 governs JIG-aligned aviation fuel quality release chains from refinery recertification through airport hydrant-dispenser Millipore/water-capsule checks before aircraft uplift. Rather than relying on informal spreadsheet overrides, the workflow enforces a documented verification gate and preserves the original observation whenever a correction is recorded.

How does petroleum distribution software handle exceptions and mismatches?

When a discrepancy occurs during petroleum distribution software, the system routes the blocked record into an owned exception queue rather than silently dropping or auto-adjusting the balance. Assigned operational, quality, and finance owners must review and approve exceptions before posting. Each exception retains the original quantity, date, and counterparty reference until the designated reviewer resolves the variance with supporting evidence.

What should teams test before automating bulk fuel inventory management?

Before scaling bulk fuel inventory management, run a bounded pilot using historical records that include partial receipts, late updates, duplicate messages, and rejected lines. Verify that the integration preserves idempotency, maintains a clear segregation of duties between operational entry and financial approval, and produces an auditable trail for every state transition.

Summary and next actions

1. Map the current aviation fuel depot quality release software record boundaries, system of record, and named approval owners before changing workflow rules.
2. Separate operational status updates from engineering, safety, or financial disposition sign-off.
3. Validate exception queues, duplicate handling, and cutoff reconciliation in a bounded pilot before production rollout.