I don't believe mechanical problems are an exemption under Israeli law. There are solutions to that (though they might be costly) other than flight cancellation.
You should probably quote the law and warn them that if your compensation will not be paid on time, they will be faced with paying legal fees too, as you will sue them in Israeli courts.
The letter of the law (in
Hebrew):
(ה) בלי לגרוע מהוראות סעיף קטן (ג), נוסע שטיסתו בוטלה לא יהיה זכאי לפיצוי כספי כאמור בתוספת הראשונה, אם מפעיל הטיסה או המארגן הוכיח כי התקיים אחד מאלה:
(1) הטיסה בוטלה בשל נסיבות מיוחדות שלא היו בשליטתו, וגם אם היה עושה כל אשר ביכולתו – לא היה יכול למנוע את ביטולה בשל אותן נסיבות;
(2) הטיסה בוטלה בשל שביתה או השבתה מוגנות;
(3) הטיסה בוטלה כדי להימנע מחילול שבת או חג.
Despite what United claims on their website that they get a pass if:
In addition, you may not be entitled to compensation if your flight
was cancelled because of special circumstances which were not under
our control, and the cancellation could not have been prevented even
if we would have taken all reasonable measures possible to avoid the
delay, or a labor strike
That is actually NOT the letter of the law. The law doesn't make any provision for "reasonable measures" (which is a subjective bar, and if it were up to judge Kavanaugh, it would be struck down as no law), but rather exempts the airline only if it wouldn't have been able to avoid the cancellation under
any circumstances (which IMHO would only mean if there's no way to get any aircraft flying out of the airport, as airlines can use other aircraft, conduct more thorough or frequent maintenance, etc. etc.) In any event, the
burden of proof is definitely on them.
https://www.elal.com/SiteCollectionDocuments/About-ELAL/Passengers-Rights/ISRAEL_AviationServicesLawENG.pdf (page 11, section 6 (e)).
(e) Without derogating from the provisions of Sub Section (c), a
passenger whose flight has been canceled will not be entitled to
monetary compensation as stated in the First Schedule, if the
Flight Operator or Organizer has proven that one of the following
prevails:
(1) the flight has been canceled due to special
circumstances which were not under its control, and even if
It would have done whatever was under its control - it could
not have prevented the cancelation due to those
circumstances;