THE 50/50 TAKE-OFF or 50 knots I.A.S. at 50% of Available Strip Length
Suggested for pilots flying any single engine normal production built aircraft - departing or taking off on any airstrip or runway surface under any wind or gradient conditions at any
height and at any temperature - where doubt may exist on accurate data on strip length and/or surface conditions including wind strength and direction
FIRST THING TO DO
Find the "middle" of the airstrip, that is, pace out the airstrip and find half or 50%
of the result
Mark this position on the side of the airstrip and make sure it will be visible to the pilot during the
take-off
TAKE-OFF
On take-off monitor the airspeed indicator and make sure it is reading 50 knots or above
as this marked mid-way point is passed - IF NOT ABORT THE TAKE-OFF!
You need 50 knots indicated at the halfway point
It is far better to remove some weight from the aircraft - if you have aborted - before trying again
Consider leaving a passenger at the airstrip to be picked up later after you have deposited some of your "weight" at a nearby longer runway - (a real life situation encountered a few times
in over 40 years flying in single-engine light aircraft ..ed)
RISK FACTOR
THE 50/50 RULE - use at your own risk not to be substituted for official Flight Manual requirements
The above calculation¹ is based on the requirement that all FAR 23 certified S/E aircraft (i.e. ...production aircraft - not home built) must have a stall speed not above 60 knots and therefore the
(recommended) take-off safety speed would be not more than 70 knots
¹ The calculation is based on the requirement to be at 70% of this "take-off safety speed" speed at 50% of the take-off distance as described in the publication by H H Hurt,
Jr, "Aerodynamics for Naval Aviators" page 393 and issued (in the U.S.A. 1960) by the Office of the Chief of Navel Operations - Aviation Training Division
If you are one of those pilots who insists on making low level turns - just like the turn onto final because you misjudged and overshot the runway - then the following may interest you
If you must do these turns be very careful - do not become complacent and end up being a "stall/spin" statistic
The suggestion¹ when carrying out this highly dangerous manoeuvre of low level turning is:
Apply aileron first to roll the aircraft - DO NOT PULL "G" - prior to roll input
When the correct angle of bank is achieved stop the roll - centre the control wheel AND THEN pull the "G"
RELEASE "G" BEFORE applying aileron to ROLL OUT of the turn
¹From personal observation spanning 35 years of piloting light aircraft most machines that impact the ground as a result of high vertical speed can be
traced back to a problem of excessive "G-PULL" control input just prior to impact
Click Image to Enlarge Left Rudder not used to lift Right Wing
You would have been taught that there is an increased stall speed during "banking" - this is true - however if the above suggestion is used it may increase your chances of
survival when operating "down low"
A Short Note
All aircraft experience a lower stall speed when operating at less than one "G" compared to the normal one "G" situation where this speed is calculated
Something to remember when and if you ever fly 'low and slow'
Always have the aircraft in a position where less than one "G" can be applied during a turn by relaxing or moving the control wheel or stick forward to create this "G" situation
of less than the normal one positive "G"
Have you ever noticed the experts doing low level aerobatics?
From personal observation - to commence a roll Bob pitches the nose of the aircraft well up then bunts forward slightly before applying aileron input creating an
environment of slightly less than one "G" - but still positive "G" - for the commencement of the manoeuvre!
Worth thinking about and applying it to your style of flying!
With apologies to those who may be offended
and to the late Sir Winston Churchill - who most definitely would be!
Never in the field of human error
has so much -
been paid to so few -
to be so wrong -
so many times...
Think about this one
You like to fly "by the book" - however the "book" cannot possibly cover all situations
So think about what you signing for with "everything/anything" associated with flying
It is far better to be "illegally" ALIVE
than "legally" DEAD
Legislation should not be used as a
substitute for "Common Sense"!
Advice from an "Old Dog" Aviator
For those of you who are about to have a "minor" mishap
that is ...you fly light aircraft on a regular basis
somewhere - sometime - it will happen!
It's not CASA you have to worry about after "dinging" your
aircraft
