PNEUMATIC SUPPLY AND ENGINE-START AIR
An electrically powered cockpit does not establish pneumatic supply. The engines, APU and a suitable high-pressure ground connection can supply the air system, subject to the appropriate configuration. Distinguish the ground electrical connection from the pneumatic source when planning a start or arranging services. [67, PDF pp. 2–4]
Follow the intended source through the bleed and crossbleed configuration towards the starter. The crossbleed valve connects the two sides when required; source selection alone does not prove that the required route is available. ECAM BLEED provides the crosscheck between the overhead selection and the actual system state. [67, PDF pp. 7–8] [68, PDF pp. 3–5]
Start and air-conditioning configurations differ, with pack-valve actions occurring automatically during the sequence. Fenix V3 models selectable aircraft standards with different pack-closing timing. Interpret the change against the selected standard and engine sequence, then establish the normal after-start supply arrangement. A change in pack sound is a cue to check the sequence, not an isolated instruction to restore a switch. [53, FADEC chapter: engine-start pack-inhibit standards] [68, PDF pp. 4–5]
Engine bleed, APU BLEED and crossbleed controls. [63, PDF p. 1]
IN PRACTICE: Establish the start-air supply
Before you begin: APU AVAIL, aircraft secure and the normal APU-assisted start planned. This exercise establishes the supply path; the actual start is performed in the engine-start chapter.
1. Call the pneumatic picture
Action. Open the ECAM BLEED page and identify the APU branch, crossbleed connection, engine branches and pack indications. Compare their present states with the selected source.
Check. You can trace the air supply that will be used, rather than using electrical power as evidence that start air must also be available. [67, PDF p. 2] [69, PDF pp. 14-16]
2. Select APU bleed when required
Action. With the APU AVAIL, select APU BLEED for the planned task. Observe the indicated valve state and the associated duct information on BLEED.
Check. The selected APU source has a visible pneumatic path; APU availability and an open bleed-supply path have been checked separately. [67, PDF p. 7] [69, PDF pp. 14-16]
3. Check the crossbleed selection
Action. Check the normal X BLEED AUTO selection and the resulting valve indication for the APU-supplied state. Read the actual indication rather than treating a selector label alone as proof of valve position.
Check. The crossbleed path agrees with the selected supply and the applicable automatic logic. [67, PDF p. 8]
4. Review the receiving system
Action. Inspect the displayed pressure/temperature and any fault indications, then compare the supply with the engine-start requirements for the loaded aircraft. Keep pack and engine-bleed selections consistent with that procedure.
Check. The displayed path is suitable for the intended next task; a merely visible pressure value has not been adopted as a universal start limit. [67, PDF pp. 3-6] [69, PDF pp. 14-16] [21, PDF pp. 103-106]
5. Expect the installed start logic
Action. During the actual start, observe the pack/valve changes specified for the installed Fenix standard. V3 models more than one start pack-inhibit standard, so use its actual configuration rather than a universal PACKS OFF instruction.
Check. The observed sequence is compared with the chosen standard. Normal automatic changes are recognised instead of being countermanded without a reason. [53, Chapter FADEC] [70, Available Options: fnx_start_pack_inhibit_type]
Complete when: The intended pneumatic source and valve path are established and understood. Start readiness is then checked against the actual engine-start procedure.