its because "while" 

while flying it  ---> kullanırken

if it was kullandığında ---> when you/he/she flies [it]

Complete the missing parts in the sentences below.

1) Onun  gelip  gelmeyeceğini bilmiyorum.

I don´t know whether he´ll come or not.

2) Yapmam  gereken  başka bir şey  var  mı ?

Is there anything else that I should do ?

3) İşlerinizi  bitirebildiniz  mi ?

Have you been able to finish your work ?

4) Gelemeyebilirim   demişti.

He [had] said  " I may not be able to come "

You don´t have any mistake KediNero.

Yes, that´s correct translation Abla. Bravo !

 One-sentence test

The plane which the pilot  had an heart attack while flying it , crashed into the lake.

Pilot..  kul........  kalp  krizi  geç......  uçak  göl.  dü...

Complete the missing parts in the sentences below.

1) On..  gel..  gelme........  bilmiyorum.

I don´t know whether he´ll come or not.

2) Yap...  ger....  başka bir ş..  var  .. ?

Is there anything else that I should do ?

3) İş........  bitir.........  mi ?

Have you been able to finish your work ?

4) Gel............   de.....

He [had] said  " I may not be able to come "

5- ´Sabahda kalmadan ben de ölüp gidecekmiş gibiydim´ 

What is the meaning of the sentence ? This one I am really not sure about. Maybe ´I felt like there was no morning left (for me) and I would also die and go.´  -  A native will help you. 

That should be without "d", --->  Sabaha  kalmadan ---> Before the morning comes

I was / felt like I was going to die [and go] before the morning comes.

 Those 3 sentences above more or less say the same thing which is -->

" I get happy when[ever] I see my mother"

So, those time gerunds are seen in following forms :

"ince[ınca/unca/ünce] 

 dığı zaman [diği zaman, duğu zaman, düğü zaman -

 dığında [diğinde, duğunda, düğünde]

  -[y] esin /ecekmişsin

-eyesin form is replaceable by -ecekmişsin form and both forms can be translated as  ´´ should ´´ form. Such as : 

- Niçin bu kadar para ödeyesin ? ---> Why should you pay this much money ?

- Niçin bu kadar para ödeyecekmişsin ? ---> Why should you pay this much money?

- Neden işi bırakasın [ki] ? ---> Why should you quit the work ?

- Neden işi bırakacakmışsın [ ki ] ? --->Why should you quit the work ?