Darth Rotor
Salted Sith Cynic
- Joined
- Aug 4, 2006
- Messages
- 38,527
That puts them at 70-85 feet MSL, depending on the ground sloping between the parking lot and the Pentagon. IIRC, having driven that road, the road to the left (west) of the Pentagon is slightly higher elevation looking east, but I couldn't swear how much, as you look from road to parking lot to Pentagon.The lamp posts were about 40 feet tall.
DR
PS: If the hijacker did not reset the altimeter to local settings in the Washington area (1/100th setting represents about a 10 foot change), or left the altimeter set to 29.92. 29.92 is the standard for altitudes above 18,000 feet. Their last cleared altitude was FL 350, or 35,000 MSL referenced to 29.92 inches Hg. (A pressure altitude, technically)
On the way back down, any difference between 29.92 and the actual barometric altimeter setting at Washington Reagan (very close to Pentagon) makes errors of AGL to MSL between 10 and 100 feet likely, assuming the altitudes from FDR are MSL and not from the Radar Altimeter. Now, if he cared to, the hijacker could have listened to the ATIS broadcast at Reagan before he began his descent to set his altimeter to the local settings. Doing so would have made his job easier, so that altitude MSL roughly equals altitude AGL, so my guess is that he might have done so, though perhaps it slipped his mind. I wonder if any FDR showed a change in Kollsman window setting.
Example of why this matters. If the altimeter setting at Reagan was 29.90 at that time, setting 29.92 in the cockpit would indicate 20 feet higher above ground than the plane actually was. Reagan being at 29.85 would put the altimeter showing the plane 70 feet higher than it was.
See where this goes, vis a vis the light poles?
DR
Last edited:
