113.—(1) Subject to paragraphs (3) and (4), an AOC holder must ensure that every relevant aircraft that is a pressurised aircraft, and that is to be operated at an altitude above flight level 100, carries on board a supply of oxygen sufficient for a duration of time that is the greater of —| (a) | the duration of time that is calculated in accordance with the Operations Manual before the commencement of the flight, being the period or periods which it is reasonably anticipated that the aircraft will be flown in the circumstances of the intended flight at an altitude where a supply of oxygen is required, and in calculating that period or those periods of time, the following factors must be taken into account:| (i) | the possibility of depressurisation when the aircraft is flying above flight level 100; | | (ii) | the possibility of failure of one or more of the aircraft engines; | | (iii) | the restrictions due to required minimum safe altitude; | | (iv) | the fuel requirements; | | (v) | the performance of the aircraft; or |
| | (b) | the duration of time that is calculated in accordance with the following Table 1 for the circumstances that the aircraft is to be operated in:| Table 1: Oxygen supply for a pressurised aircraft |
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| (1) | When flying above flight level 100 but not exceeding flight level 250 |
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| | (a) | every flight crew member |
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| | 30 minutes or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is greater. |
| | | (b) | every cabin crew member and 10% of passengers |
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| | (i) | When the aircraft is capable of descending and continuing to its destination as specified in Capability 1, 30 minutes or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is greater. |
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| (ii) | When the aircraft is not capable of descending and continuing to its destination as specified in Capability 1, whenever the cabin pressure altitude is greater than 10,000 ft but does not exceed 12,000 ft. |
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| | | (c) | every cabin crew member and all passengers |
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| | When the aircraft is not capable of descending and continuing to its destination as specified in Capability 1, and the cabin pressure altitude exceeds 12,000 ft, the period when the cabin pressure altitude exceeds 12,000 ft or 10 minutes whichever is greater. |
| | (2) | When flying above flight level 250 |
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| | (a) | every flight crew member |
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| | 2 hours or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is greater. |
| | | (b) | every cabin crew member |
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| | Whenever the cabin pressure altitude exceeds 10,000 ft and a portable supply for 15 minutes. |
| | | | Whenever the cabin pressure altitude exceeds 10,000 ft, but does not exceed 12,000 ft. |
| | | | Whenever the cabin pressure altitude exceeds 12,000 ft, but does not exceed 15,000 ft. |
| | | | If the cabin pressure altitude exceeds 15,000 ft, the period when the cabin pressure altitude exceeds 15,000 ft or 10 minutes, whichever is greater. |
| | | (f) | 2% of passengers or 2 passengers, whichever is greater, being supply of first‑aid oxygen which must be available for simultaneous first‑aid treatment of 2% or 2 passengers wherever the passengers are seated in the aircraft |
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| | Whenever after decompression, if cabin pressure exceeds 8,000 ft. |
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(2) In Table 1, “Capability 1” means that, at the time a failure to maintain cabin pressure occurs, the aircraft is capable of —| (a) | descending to flight level 130 within 4 minutes, in accordance with the emergency descent procedure specified in the relevant aircraft flight manual and without flying below the minimum altitudes for safe flight specified for the aircraft in the AOC holder’s Operations Manual or equivalent; and | | (b) | continuing at or below that flight level to its intended destination or any other place at which a safe landing can be made. |
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(3) An AOC holder may, in lieu of complying with paragraph (1), comply with paragraph (4) if the relevant aircraft —| (a) | has a Certificate of Airworthiness that was first issued (whether in Singapore or elsewhere) before 1 January 1989; and | | (b) | is provided with means for maintaining a pressure greater than 700 hPa throughout the flight in the flight crew compartment and in the compartments in which passengers are carried. |
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(4) The supply of oxygen to be provided for the purposes of paragraph (3) is —| (a) | in every case where a relevant aircraft is to be flown above flight level 350, a supply of oxygen in a portable container sufficient for the simultaneous first-aid treatment of 2 passengers; and | | (b) | in the event of failure to maintain a pressure greater than 700 hPa in accordance with paragraph (3)(b) in the circumstances described in columns 1 and 2 of the following Table 2, a supply of oxygen sufficient for continuous use by the persons specified in column 3 for the period specified in column 4 of the Table:| Table 2: Alternative oxygen supply |
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| Aircraft to operate at altitudes |
| | Capability of aircraft to descend (where relevant) |
| | Persons for whom oxygen is to be provided |
| | Period of supply of oxygen |
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| | | Every crew member and any passenger for whom oxygen is provided as specified below |
| | 30 minutes or the period specified at Condition A, whichever is greater. |
| | Above flight level 100 but not above flight level 300 |
| | Aircraft is either flying at or below flight level 150 or is capable of descending and continuing to destination as specified at Condition X |
| | | 30 minutes or the period specified at Condition A whichever is greater. |
| | | Aircraft is flying above flight level 150 and is not capable of descending and continuing to destination as specified at Condition X |
| | | 10 minutes or the period specified at Condition B, whichever is greater. |
| | | | | 30 minutes or the period specified at Condition C, whichever is greater. |
| | Above flight level 300 but not above flight level 350 |
| | Aircraft is capable of descending and continuing to destination as specified at Condition Y |
| | | 30 minutes or the period specified at Condition A, whichever is greater. |
| | | Aircraft is not capable of descending and continuing to destination as specified at Condition Y |
| | | 10 minutes or the period specified at Condition B, whichever is greater. |
| | | | | 30 minutes or the period specified at Condition C, whichever is greater. |
| | | | | 10 minutes or the period specified at Condition B, whichever is greater. |
| | | | | 30 minutes or the period specified at Condition C, whichever is greater. |
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(5) In Table 2 —| “Condition A” means the whole period during which the aircraft flies above flight level 100 after a failure to maintain a pressure greater than 700 hPa in the control department and in the compartments in which passengers are carried has occurred; |
| “Condition B” means the whole period during which the aircraft flies above flight level 150 after a failure to maintain a pressure greater than 700 hPa in the control department and in the compartments in which passengers are carried has occurred; |
| “Condition C” means the whole period during which the aircraft flies above flight level 100, but not above flight level 150, after a failure to maintain a pressure greater than 700 hPa in the control department and in the compartments in which passengers are carried has occurred; |
“Condition X” means that, at the time when a failure to maintain a pressure greater than 700 hPa in the control department and in the compartments in which passengers are carried occurs, the aircraft is capable of —| (a) | descending to flight level 150 within 6 minutes, in accordance with the emergency descent procedure specified in the relevant aircraft flight manual and without flying below the minimum altitudes for safe flight specified for the aircraft in the AOC holder’s Operations Manual or equivalent; and | | (b) | continuing at or below that flight level to its place of intended destination or any other place at which a safe landing can be made; |
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“Condition Y” means that, at the time when a failure to maintain a pressure greater than 700 hPa in the control department and in the compartments in which passengers are carried occurs, the aircraft is capable of —| (a) | descending to flight level 150 within 4 minutes, in accordance with the emergency descent procedure specified in the relevant aircraft flight manual and without flying below the minimum altitudes for safe flight specified for the aircraft in the AOC holder’s Operations Manual or equivalent; and | | (b) | continuing at or below that flight level to its place of intended destination or any other place at which a safe landing can be made. |
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(6) An AOC holder must ensure that a relevant aircraft that —| (a) | is intended to be operated at flight altitudes above flight level 250; or | | (b) | is not capable of descending from an altitude of flight level 250 to flight level 130 within 4 minutes, in accordance with the emergency descent procedure specified in the relevant flight manual and without flying below the minimum altitudes for safe flight specified for the aircraft in the AOC holder’s Operations Manual or equivalent, |
| is equipped with suitable and sufficient apparatus to enable the persons for whom oxygen is supplied to use the oxygen, including automatically deployable oxygen equipment with a quantity of oxygen dispensing units that exceeds the number of passenger and cabin crew seats by at least 10%. |
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| (7) An AOC holder must ensure that, in every small aeroplane that is a pressurised aeroplane and that is to be operated at any altitude above flight level 250, each flight crew member at the flight duty station has ready access from the crew member’s normal seating position to a quick‑donning type of oxygen mask that will readily supply oxygen on demand. |
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