Wait — option a says DOI = 114.8 → difference = 2.4. That means Crew index = 2.4. Then 2.4 = (410 × 142) / CF → CF = (410 × 142) / 2.4 ≈ 24,258. So CF = 24,258. Then BEM index = (34,560 × arm_BEM) / 24,258 = 112.4 → arm_BEM = (112.4 × 24,258) / 34,560 ≈ 78.9 m — plausible.
Crew added index = 114.8 – 112.4 = 2.4. Then 2.4 = (410 × arm)/CF → CF = (410 × 142)/2.4 ≈ 24,258 — not round. easa atpl question bank
First, convert BEM and crew items into moment index. Wait — option a says DOI = 114
Total DOI = BEM index + Crew Index = 112.4 + 5.8 = ? That doesn’t match any option — contradiction. So CF = 24,258
Given the options, correct calculation is:
From BEM: Index 112.4 at 34,560 kg implies: Index = (Mass × Arm) / 1000? Let’s check: (34,560 × Arm_BEM)/1000 = 112.4 → Arm_BEM = (112.4 × 1000) / 34,560 ≈ 3.25 — impossible (too small). So not /1000.
Index formula typically: , but in this question bank, they provide index directly for BEM and arm values for others. We must compute additional moment index from crew: