Table 1: Defining the search width Probability of Assumptions: Dimensions: Resultant search Comments: including the length along the (Add ±5 NM to all the distances due to the tolerance in the position of the arc) wreckage site: arc: Higher Max. distance unpowered glide B777 from FL350 (120 NM). ± 125 NM 70 NM (250 NM) 130 km Max. distance unpowered glide from OEI altitude of FL290 (90 NM). ± 95 NM 103 NM Given the uncertainty of where the aircraft crossed the arc, these search (190 NM) 191 km widths give impractically small search lengths along the arc. Realistic distance unpowered glide (60 NM) from FL290 to extend range but no turn back. + 65 NM 206 NM - 20 NM 381 km (85 NM) ± 30 NM 292 NM No pilot or autopilot inputs Reasonable search width. Use distances from BEA/ATSB study of loss of control accidents (20 NM) plus 5 NM (60 NM) 540 km + 30 NM No pilot or autopilot inputs 350 NM Use distances from BEA/ATSB study plus 5 NM - 20 NM Reasonable search width. Moving in direction of previous track i.e. reduce direction by 10 NM ‘–‘ 648 km (50 NM) + 25 NM The BEA/ATSB case studies No pilot or autopilot inputs 437 NM Use distances from BEA/ATSB study generally involve rapidly developing -15 NM Moving in direction of previous track i.e. reduce direction by 5 NM descents and short total upset ‘–‘ 810 km durations (most cases are < 2 (40 NM) minutes). MH370 may not correlate No pilot or autopilot inputs well with the case studies and the 20 + 20 NM Use distances from BEA/ATSB study NM distance suggested from the 583 NM Moving in direction of previous track i.e. reduce direction by 5 NM ‘–‘ -10 NM study might not be applicable. A buffer Lower 1,080 km Ignore ±5 NM arc tolerance above the 20 NM distance is (30 NM) advisable.
Table 1: Defining the search width Probability of including the wreckage site: Assumptions: (Add ±5 NM to all the distances due to the tolerance in the position of the arc) Dimensions: Resultant search length along the arc: Comments: Higher Lower Max. distance unpowered glide B777 from FL350 (120 NM). ± 125 NM (250 NM) 70 NM 130 km Given the uncertainty of where the aircraft crossed the arc, these search widths give impractically small search lengths along the arc. Max. distance unpowered glide from OEI altitude of FL290 (90 NM). ± 95 NM (190 NM) 103 NM 191 km Realistic distance unpowered glide (60 NM) from FL290 to extend range but no turn back. + 65 NM - 20 NM (85 NM) 206 NM 381 km No pilot or autopilot inputs Use distances from BEA/ATSB study of loss of control accidents (20 NM) plus 5 NM ± 30 NM (60 NM) 292 NM 540 km Reasonable search width. No pilot or autopilot inputs Use distances from BEA/ATSB study plus 5 NM Moving in direction of previous track i.e. reduce ‘–‘ direction by 10 NM + 30 NM - 20 NM (50 NM) 350 NM 648 km Reasonable search width. No pilot or autopilot inputs Use distances from BEA/ATSB study Moving in direction of previous track i.e. reduce ‘–‘ direction by 5 NM + 25 NM -15 NM (40 NM) 437 NM 810 km The BEA/ATSB case studies generally involve rapidly developing descents and short total upset durations (most cases are < 2 minutes). MH370 may not correlate well with the case studies and the 20 NM distance suggested from the study might not be applicable. A buffer above the 20 NM distance is advisable. No pilot or autopilot inputs Use distances from BEA/ATSB study Moving in direction of previous track i.e. reduce ‘–‘ direction by 5 NM Ignore ±5 NM arc tolerance + 20 NM -10 NM (30 NM) 583 NM 1,080 km