Thanks MFS. We're discussing this in the office Looking at the regs I have two areas where thrust might be relevant, 25.107(e)(1)(iii) or 25.107(e)(3). The first is the VR V2 speed spread but could para 3 be an issue on the 737?
I'm sure you know the JARs, to save you looking them up:
JAR 25.107(e) VR, in terms of calibrated air speed, must be selected in accordance with the conditions of subparagraphs (1) to (4) of this paragraph:
(1) VR may not be less than –
(i) V1;
(ii) 105% of VMC;
(iii) The speed (determined in accordance with JAR 25.111(c)(2)) that allows reaching V2 before reaching a height of 35 ft above the take-off surface; or
(iv) A speed that, if the aeroplane is rotated at its maximum practicable rate, will result in a VLOF of not less than –
[(A) 110% of VMU in the all-engines-operating condition and] 105% of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition; or
[(B) If the VMU attitude is limited by the geometry of the aeroplane (i.e., tail contact with the runway), 108% of VMU in the all-engines-operating condition and 104% of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition. (See ACJ 25.107(e)(1)(iv).) ]
(2) For any given set of conditions (such as weight, configuration, and temperature), a single value of VR, obtained in accordance with this paragraph, must be used to show compliance with both the one-engine-inoperative and the all-engines-operating take-off provisions.
(3) It must be shown that the one-engine-inoperative take-off distance, using a rotation speed of 5 knots less than VR established in accordance with sub-paragraphs (e)(1) and (2) of this paragraph, does not exceed the corresponding one-engine-inoperative take-off distance using the
established VR. The take-off distances must be determined in accordance with JAR 25.113(a)(1). (See ACJ 25.107(e)(3).)