ATA 73 Engine Fuel and Control

LEGEND

Procedures Required

(O) – An operational procedure
(M) or (M#) – A maintenance procedure
(O)(M) or (O)(M#) – Both operational and maintenance procedures

Repair Interval Categories

Category A

Items in this category shall be repaired within the time interval specified in the "Remarks or Exceptions" column of the air operator's approved MEL. Whenever the proviso in the "Remarks or Exceptions" column of the MMEL states cycles or flight time, the time interval begins with the next flight. Whenever the time interval is listed as flight days, the time interval begins on the flight day following the day of discovery.

Time Limited Dispatch - Some MMEL's for aircraft that are equipped with FADEC engines have relief that is subject to time limited dispatch expressed as a specific number of engine hours, and will start in accordance with the times established by the engine manufacturer or as indicated in the remarks column of the MMEL. Time limited relief cannot be extended.

Category B

Items in this category shall be repaired within 3 consecutive calendar days excluding the day of discovery.

Category C

Items in this category shall be repaired within 10 consecutive calendar days, excluding the day of discovery.

Category D

Items in this category shall be repaired within 120 consecutive calendar days, excluding the day of discovery. To be considered for placement in Category D, the item must be of an optional nature, or excess equipment which an air operator may, at his/her discretion, deactivate, remove from or install on an aircraft.

To be approved for Category D, the item must meet the following criteria:

  1. the absence of the item does not adversely affect crew member's workload;
  2. the crew members do not rely on the function of that item on a routine or continuous basis; and,
  3. the crew members' training, subsequent habit patterns and procedures do not rely on the use of that item.

Category D relief will generally not be approved for equipment which is considered to increase the level of safety, even if that equipment is of an optional nature.

ITEM:  73-20-1  FULL AUTHORITY DIGITAL ELECTRONIC CONTROL (FADEC)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Full Authority Digital Electronic Control (FADEC) A - - May be dispatched with FADEC faults provided repairs are made in accordance with times established by either engine or aircraft manufacturer, whichever is more restrictive. No repair or inspection interval extensions are permitted.

DISCUSSION:

References:  FAA PL 45 (Rev. 2, 4 Mar. 2004)

The above-mentioned generic phraseology is only a guide for the development of MELs.  Details of reporting requirements, relief requested and granted, etc. will be resolved at the MMEL level with TCCA National Aircraft Certification.

Other items covered under the TCDS Time Limited Dispatch (TLD) analysis may also be included in the MMEL in their respective ATA chapters.

It is noted that these items must not be extended under the MEL extension program.  Therefore the following guidelines apply:

1. MELs must be developed with FADEC reference specifically to the operator’s equipment and applicable TCDS limitations.  With respect to FADEC system TLD operations, the more restrictive of the engine or aircraft manufacturer’s limitations must be applied,

2. TCDS-controlled items are not to be extended under current MEL extension guidelines,

3. TLD certification requirements are accomplished within the established time intervals,

4. TLD certification requirements are not adjusted or extended without TCCA National Aircraft Certification Engineering approval,

5. TLD reliability reporting requirements are being met, and

6. Operators are advised that failure to comply with the engine or aircraft TCDS requirements related to TLD, whichever is more restrictive, would be contrary to the intent of MMEL relief, and could result in loss of TLD authorization.

FAA Differences:  FAA relief is identical to TCCA.

ITEM:  73-30-1  FUEL FLOW/PRESSURE INDICATIONS

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Fuel Flow/Pressure Indications B/C - - One may be inoperative provided appropriate related engine instruments and fuel quantity indications are operative.

DISCUSSION:

References:  AWM 523.1305(c)(2), AWM 525.1305(b)(5) and (c)(2), FAA PL 11 (Rev. 1, 15 Aug. 1997)

Appropriate related engine instruments could be, for example, N1, N2, etc. (aircraft specific) which would permit an assessment of engine performance without fuel flow information.

The determination of the B or C category is dependent upon the engine instrumentation configuration of the specific aircraft being evaluated.

FAA Differences:  FAA assigns cat C to B767, cat B to SAAB 340.  FAA does not permit relief for analogue readout of fuel pressure indication.

Date modified: