{"id":"F2008L04322","name":"AD/GY80/8 - Aeroplane Operating Manual - Fuel Conversion Tables","slug":"ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76310,"registerId":"commonwealth-F2008L04322-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Aerospatiale GY 80 (Horizon) Series Aero","sectionType":"division","heading":"Aerospatiale GY 80 (Horizon) Series Aeroplanes","content":"### Aerospatiale GY 80 (Horizon) Series Aeroplanes\n\n| AD/GY80/8 | Aeroplane Operating Manual - FuelConversion Tables | 1/2009 TX |\n| --------- | -------------------------------------------------- | --------- |\n\n```html\n

Applicability:

(SUD AVIATION, Yves Gardan) GARDAN Model GY 80 series aeroplanes.

Requirement:

1. The use of the unit conversion scales (US Gallon to Imperial Gallon and US Gallon to Litre) indicated on the O-360-A engine fuel consumption curve on Chapter III Page 23 of the GY 80 English Language Operating Manual, dated
1 January 1966, is forbidden.

2. The following conversion data must be used as reference in order to replace the incorrect conversion scales:

(a) Conversion coefficients:

1 US Gallon = 0.8326738 Imperial Gallon = 3.785412 Litre

1 Litre = 0.2641721 US Gallon = 0.2199692 Imperial Gallon

1 Imperial Gallon = 1.20095 US Gallon = 4.546092 Litre

(b) Conversion Tables:

US Gallons

Imperial Gallons

Litres

5

4.2

18.9

6

5

22.7

7

5.8

26.5

8

6.7

30.3

9

7.5

34

10

8.33

37.8

11

9.16

41.6

12

10

45.4

\n```\n\n```html\n

13

10.8

49.2

14

11.7

53

15

12.5

56.8

16

13.3

60.6

17

14.16

64.4

Imperial Gallons

US Gallons

Litres

4

4.8

18.2

5

6

22.7

6

7.2

27.3

7

8.4

31.8

8

9.6

36.4

9

10.8

40.9

10

12

45.5

11

13.2

50

12

14.4

54.6

13

15.6

59.1

14

16.8

63.7

Litres

US Gallons

Imperial Gallons

20

5.3

4.4

25

6.6

5.5

30

7.9

6.6

35

9.25

7.7

\n```\n\n```html\n

40

10.6

8.8

45

11.9

9.9

50

13.2

11

55

14.5

12.1

60

15.85

13.2

65

17.2

14.3

3. Insert a copy of this AD in the GY 80 Operating Manual facing Page 23 of Chapter III.

The requirements of this AD may be accomplished and certified by a pilot holding an endorsement for the aircraft.

Note 1: As the type certificate of the GY 80 aeroplane has been surrendered (“orphan” aircraft), the Operating Manual will not be revised by any type certificate holder.

Note 2: EASA Emergency AD 2008-0200-E dated 13 November 2008 refers.

Compliance:

Before further flight after the effective date of this AD, unless previously accomplished.

This Airworthiness Directive becomes effective on 18 November 2008.

Background:

A mistake has been found in the GY 80 English Language Operating Manual, dated
1 January 1966. This mistake concerns the unit conversion scales indicated on the fuel consumption curve for Lycoming O-360-A engine and it may have been the cause of an accident.

To address this condition, this AD forbids the use of the existing conversion scales and provides correct conversion data to be inserted into the Aeroplane Operating Manual.

\n```\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n14 November 2008","sortOrder":0},{"sectionNumber":"AD/GY80/8","sectionType":"part","heading":"AD/GY80/8","content":"## AD/GY80/8","sortOrder":1},{"sectionNumber":"Aeroplane Operating Manual - FuelConvers","sectionType":"part","heading":"Aeroplane Operating Manual - FuelConversion Tables","content":"## Aeroplane Operating Manual - Fuel \nConversion Tables","sortOrder":2},{"sectionNumber":"1/2009 TX","sectionType":"part","heading":"1/2009 TX","content":"## 1/2009 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD does not broaden or narrow the class of affected aircraft; it applies to Aerospatiale GY 80 series and mechanically replaces incorrect fuel conversion data in the existing Operating Manual. It mandates insertion of corrected coefficients/tables and sets a compliance deadline, but does not add new operational limitations or extend applicability beyond the GY 80 series."},"complexity_factors":["Narrow technical fix: replaces and forbids specific conversion scales with precise coefficients and tables (Requirement 1 & 2(a)/(b))","Immediate compliance timing: 'Before further flight after the effective date' creates low operational disruption but strict deadline (Compliance)","Simple administrative action: insertion of AD copy facing Chapter III p.23 (Requirement 3)","Certification flexibility: a pilot with the aircraft endorsement may accomplish and certify the action, reducing need for licensed maintenance (certification note)","Orphan/type-certificate issue: type certificate surrendered so manual will not be revised by a holder, requiring owners/operators to apply AD changes themselves (Note 1)","Safety rationale stated: AD cites possible causal link to an accident, but provides only numerical correction—not procedural or equipment changes (Background)"],"plain_english_summary":"This Airworthiness Directive for Aerospatiale GY 80 (Horizon) series aeroplanes forbids use of the incorrect US-to-Imperial/Litre fuel conversion scales shown on Chapter III, page 23 of the English Operating Manual and requires inserting specified conversion coefficients and replacement tables into the manual. Compliance is required before further flight and may be certified by a pilot holding the aircraft endorsement. The AD states the manual error may have contributed to an accident, so it corrects the fuel‑quantity conversion data used by owners and operators."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific technical error in a specific aircraft manual. It has not expanded beyond its original purpose of correcting fuel conversion data for the GY 80 aircraft."},"complexity_factors":["Single, narrow applicability (one specific aircraft model series)","Two clear prohibitions and one positive requirement","No defined terms section or interpretive provisions","No cross-references to other legislation","Straightforward compliance mechanism (insert copy of AD in manual)","Self-certification permitted by endorsed pilots","Contains only factual conversion tables and procedural instructions"],"plain_english_summary":"This AD bans use of the fuel-unit conversion scales in the original 1966 Aerospatiale GY 80 (Horizon) operating manual, supplies corrected US/Imperial/litre conversion figures, and requires the directive be inserted into the aircraft’s operating manual. It affects owners, operators and pilots of GY 80 series aircraft, including pilot-operators with the appropriate endorsement.\n\nCASA issued this safety order because the incorrect charts can cause fuel miscalculation and exhaustion; the change was mandatory before flying again after 18 November 2008."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables","history":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables/history","analysis":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables/analysis","conflicts":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables/conflicts","importantCases":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables/important-cases","documents":"/api/acts/ad-gy80-8-aeroplane-operating-manual-fuel-conversion-tables/documents"}}