OXYGEN SYSTEM
DESCRIPTION
The oxygen system of the T Mk. 5 and T Mk. 55 Lightnings is split into two main areas:
- for storage, the cryogenic liquid oxygen package unit mounted behind the cockpit;
- and for delivery, the remote controlled demand oxygen system assemblies (x2) mounted to the ejection seats.
LIQUID OXYGEN PACKAGE UNIT
The liquid oxygen (LOX) package unit provides storage of liquid oxygen in two self pressurising 3.5 litre dewar containers/vessels. A pressure-raising coil pipe is fitted to each container; when liquid oxygen is allowed to pass into the ambient temperature coil pipe it vaporises to gaseous oxygen, in doing so increasing in volume, but as the unit is sealed, the pressure rises.
This package provides high pressure oxygen to the seat mounted regulators, it is fitted with certain valves for filling and pressure relief, details can be found in the Vol. 1 section, see references.
The aircraft APs didn't provide the manufacturer of the LOX system, however BOC include numerous references to the Lightning in their 1960's LOX adverts as found on Aviation Ancestry ↗.
BOC liquid oxygen systems
Published: Flight, 30th August 1962
Source: Aviation Ancestry ↗
BOC liquid oxygen systems
Published: Aeroplane, 1st September 1966
Source: Aviation Ancestry ↗
REMOTE CONTROLLED DEMAND OXYGEN SYSTEM
Gaseous oxygen is supplied at high pressure to a quick release connector on the stbd sides of the ejection seats. The seat carries a sub-assembly including a type 120 demand regulator to provide lower pressure oxygen to the aircrew upon demand (breathing in).
The sub-assembly also carries an emergency oxygen cylinder and standby regulator to provide oxygen during ejection, or in flight if the main system fails.
Both regulators supply oxygen to the seat portion of the PEC (Personal Equipment Connector) by a port at the rear, the PEC aircraft portion only having ports for anti-G trousers/suit and AVS (Air Ventilated suit); in contrast to the single-seat Lightnings and T Mk. 4, where the aircraft portion carries all three gaseous services.
A.P.3456E, Part 1, Sect. 2, Chap. 1, A.L.14, Mar. 1984, Fig 23
T5 Lightning seat mounted oxygen sub-assembly
Normalair seat mounted oxygen regulator system
Published: Flight, 14th September 1961
Source: Aviation Ancestry ↗
Note: The seat mounted system is only used in the T Mk. 5 and T Mk. 55 Lightnings, other Mk.s use a cockpit mounted regulator, and 3 port aircraft portion of the PEC.
The image below shows the seat portion PEC with top and bottom dust covers in place, the bottom (aircraft portion) dust cover is shorter then the top (aircrew portion) as it has no oxygen port:
A.P.101B-1005-1A, Sect. 1, Chap. 1, A.L.47, Oct. 1969, Fig 3
T5 Lightning seat mounted oxygen sub-assembly
AIRCREW EQUIPMENT
The system is designed to support breathing at low and high altitudes, using an oxygen mask Type P2, P2A, Q2 or Q2A. Alternatively, if it's the early 1960's, a BWT Type E partial pressure helmet can be used. For higher altitudes, a pressure jerkin Mk. 4, or combined pressure and anti-G suit can also be used with either a P/Q mask or partial pressure helmet.
The removable "man portion" of the PEC (Personal Equipment Connector) connects the mask/helmet to the seat portion PEC via an oxygen hose, and also carries connections for Mic/Tel, anti-G trousers and AVS (Air Ventilated Suit. Suitable PEC's are the oxygen hose Mk. 1 or Mk. 1A, or pressure jerkin hose Mk. 2.
F Mk. 3 Lightning aircrew equipment assemblies (AEA)
ML Aviation 1966
REFERENCES
T Mk.5 mechanical "Vol. 1":
A.P.101B-1005-1A, Sect. 3, Chap. 10, A.L.56, Oct. 1971 - Oxygen System
F Mk. 3, T Mk. 5 and F Mk. 6 aircrew manual:
A.P.101B-1003, 5 & 6A, Part 1, Chapter 12, A.L.2, Nov. 1984, Pilot Equipment and Associated Systems - Paragraph 59
Aircrew Equipment Assemblies:
A.P.1182, Sect. 1, Chap. 5, A.L.30, Oct. 1959 - Personal Equipment Connector
A.P.1182, Vol. 1, Book 2, Sect. 16, Chap. 5, A.L.103, Mar. 1966 - Lightning T Mk. 5, Mk. 4BSB Ejection Seat
A.P.1182E, Vol. 1, Sect. 1, Chap. 22, A.L.97, Jan. 1963 - Pressure Jerkin Mk. 4
A.P.1182E, Vol. 1, Sect. 1, Chap. 23, A.L.98, Jan. 1963 - Partial Pressure Helmet, Type E - (BWT)
A.P.1182E, Vol. 1, Sect. 4, Chap. 6, A.L.117, Nov. 1965 - Oxygen Masks, Type P and Q
A.P.1182E, Vol. 1, Sect. 4, Chap. 8, A.L.107, Mar. 1964 - Oxygen Hose Assemblies - Low Altitude PECs
A.P.1182E, Vol. 1, Sect. 4, Chap. 9, A.L.104, Jan. 1964 - Pressure Jerkin Hose Assemblies - High Altitude PECs
General and Technical Information:
A.P.108F-0902-12, Jan 1987, Oxygen Masks, Types P and Q
A.P.108F-0904-12, Jan 1987, Oxygen Hose Assemblies
Flying - The Aircrew, Airmanship and Aircraft Performance:
A.P.3456E, Part 1, Sect. 2, Chap. 1, A.L.14, Mar. 1984 - Oxygen Equipment and Assemblies
ML Aviation:
ML Aviation, July 1975 Hose Assemblies and Connectors
ML Aviation, 1966, F Mk. 3 Lightning aircrew equipment assemblies (AEA)
Airmed:
Airmed, A-201, Ed.3, 1963, Oxygen Masks For Service Aircraft
MSA Catalyst Division:
MSA, Oxygen Mask Advert (date unknown)