Page 27 - InterPilot 2018, Issue 4

PAGE 27

Founding MAs: VNV THe prIor KnowleDge of THe TesT pIloT

The realisation that this definition did not match
reality developed over the following years. Of
The Dutch Need More Time course, it had served its purpose when testing
new airplanes. But herein lies the problem. Dur-
ing the test phase for new airplanes, a rejected
take-off is included in the programme. The test
pilot knows in advance that he will close the gas
and apply the brakes. His full attention will be
focused on this. He closes the thrust levers and
slows down the aircraft at exactly V1. When the
VERENIGING NEDERLANDSE VERKEERSVLIEGERS aircraft stops at the very last centimetre of the
runway, the test has been a success.

we are noT as gooD
Reality is different. That is why the definition of
ince we began V1 needed to change. In the Netherlands, Henk
flying aircraft, The thrust levers are moved forward. The not? What do you do? Stop or continue? Bilderdijk, chair of the airworthiness commission
the definition and engines slowly start to spin-up and pro- and later president of the VNV, took on the task
calculation of V1 duce that wonderful, distinctive sound. THe olD MeTHoD of researching this issue.
shas been amend- The airplane starts to move. The centre As we fly with turbofans, we use V1 in the
ed several times. This is line moves beneath you. Slowly, fast, fast- same way. However, the time we have He approached his work with caution. The rea-
mainly down to the coop- er, fastest. V1 is approaching. The speed gained to think and respond is different sons to adjust V1 were not based on an incor-
eration of the Dutch alpa picks up. When we delve into the archives of the rect decision made in the past, but the changing
(VnV), Ifalpa, and ICao. American Congress, the Federal Register times made it apparent that something needed
Thanks to the efforts of Suddenly you notice something isn’t right. of 1964 states the definition of the accel- to be done. Or as he diplomatically put it, “It is
these organisations in the You see something, hear something, feel erate-stop distance that was applied in the clear that we are not as good as they thought
1970s, pilots have gained something, or you experience all of these early years of jet planes. It is defined like we were.”
more time to make an in- things at once. You haven’t quite passed an on-off switch. Accelerate up to V1, then
formed decision. V1. This is the point at which you need to brake. V1 does not contain any time in it- So, research began into an improved V1 in little
make a decision. Is it a serious problem or self. It is nothing.
old Holland, with the full awareness that we were
too small as a nation to determine new global
legislation, but as a founding member, we had
the support of IFALPA.

Two eXTra seConDs
Dutch research mainly focused on thinking and
response time. In the calculation, a formula had
to be found that took account of time to no-
ABOVE
From the National tice, process, and respond to the problem. After
Archives of the United thorough research, which examined the effect of
States, Federal Register, startle and surprise on the pilot, engine failure
V29, N250, Washington, speed (Vef) was introduced. This was the point at
24 December 1964
which V1 was first measured. Only two seconds
after VEF, V1 is expected.

In the interim seconds, it was assumed that the
engine(s) continue to accelerate at full power.
Action was only taken at V1. That is why the cal-
culations had to be amended. There was global
agreement on this.

TIMe To aCT
However, action after V1 needs time and, as a
result, distance. According to the researchers,
this also had to be considered. This was less un-
derstood by the authorities. They found that two
seconds were more than enough for everything.
The Dutch researchers noted the differ-ence of
opinion in their report. The Dutch researchers
needed to defend their position and found an
ally in IFALPA.