London's Air Ambulance is trying to raise £4.4 million to buy a second helicopter.
Currently the capital has only one emergency helicopter, which was unavailable for 55 days last year due to maintenance.
£1.6 million has already been raised and the money would help to extend daylight flying hours for the next five years.
The London Air Ambulance is celebrating 25 years of service. Since the charity launched in 1988, the trauma team have helped more than 30,000 critically injured people in the capital.
The charity is reliant on donations to maintain its service and hopes to recruit more emergency service workers to extend its daylight flying hours during the summer months.
The largest crane in Europe has been put up in South London, as work begins on a new helipad for a hospital in Tooting.
St George's will become the second hospital in the capital to have an emergency landing pad.
It will give victims of major trauma - like road accidents, falls and stabbings - faster access to potentially life-saving treatment.
Ria Chatterjee reports.
The new helipad - London's second and the first in South London - will support air ambulances bringing the most seriously injured casualties for emergency treatment at St George's, which provides the Major Trauma Centre for the South West London and Surrey Trauma Network.
Heather Jarman, Clinical Director for Major Trauma at St George's Hospital told us which patients will benefit from the new helipad.
The helipad will help save the lives of people living, working and commuting in London by significantly reducing transfer times to the Major Trauma Centre at St George's Hospital.
Patients with serious injuries, such as those caused by road accidents, shootings, stabbings, major burns and falls from height can be treated more quickly, rather than being taken to hospitals further afield, often flying over St George's.
The HELP Appeal, which has provided a grant of £1 million towards the construction of the helipad at St George's Hospital, is a charity established by the County Air Ambulance Trust.
It relies entirely on charitable donations and is raising much needed funds to help finance helipad facilities at key emergency departments across the county.
The Appeal provides non-repayable grants to hospitals looking to build their own helipads or update existing facilities.
Partly funded by The HELP (Helicopter Emergency Landing Pads) Appeal, a 25m by 25m helipad will enable seriously ill patients to be brought by air ambulance for treatment at the hospital's Major Trauma Centre.
A lift shaft in the middle of the wing is being built so that patients can be lowered quickly and smoothly into the hands of medical experts.
The helipad - which is due for completion in January 2014 - is being constructed by Miller Construction and will be the second hospital helipad in London and the first south of the river.
The pilots flying around the World non stop - for seven days - to raise money for the London Air Ambulance.
They'll be in a Boeing 737, that will land and take off at over 45 airports.
So how are they doing it without actually going anywhere? Paul Brand can explain.
London's Air Ambulance have begun using new equipment which will help medics to save more lives.
The hand-held scanner provides clear ultrasound images to help doctors quickly assess whether a patient has internal injuries.
London's Air-Ambulance became Britain's first emergency service to carry blood whenever they're called to an accident. Experience has shown that when soldiers have been seriously injured in battle, an immediate blood transfusion can increase their chances of survival.
Phil Bayles reports now on how the same pricinple will now be applied around the capital.