BK117/EC145/Lakota: Can it fly with the rear doors removed?

[Able Dart]

I realise this is probably a complete zoomer question but I'd be grateful for a serious answer.

I've never seen this, while I have seen any number of military types with rear ramp doors fly with them open. Also Mi-8/17 with clamshell doors removed, but not the 117.

Is the trim penalty just too big with a craft the size of the 117? Would partial opening of the crew doors help?

I've searched the forum and found out about the side doors issue, and how it's not a cabin integrity issue, but nothing really about the rear clamshell doors.

Thoughts? Thanks in advance.

[skadi]

Flight is approved with the clamshell doors removed:

For the BK117 B2 see FM 11-3 2.5.3.

For the BK117 C2 ( EC 145 ) see FM 9.1-2 5.1 ( All other doors also have to be removed )

skadi

[Flying Bull]

FLIGHT MANUAL BK117 B-2


SUPPLEMENT FOR
OPERATION WITH OPENED/REMOVED DOORS

FLIGHT MANUAL BK117 B-2

1. GENERAL
   For special missions the helicopter can be operated with
   
   • – opened or removed cockpit door(s)
   • – opened or removed sliding door(s)
   • – removed clam shell doors (removable in pairs only)
     including all possible combinations of the above mentioned conditions, when the following limitations and procedures are complied with.
2. LIMITATIONS

• 2.1 KINDS OF OPERATION
  CAT A operation is not permissible with door(s) opened/removed.
• 2.2 AIRSPEED LIMITS
  With both clam shell doors removed and simultaneously the cabin sliding
  door(s) opened but installed, the VNE is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 KIAS. In all other cases the VNE is as shown on the table in Section 2,
  however limited to a maximum of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 KIAS.
  The VNE for steady autorotation under all conditions is . . . . . . . . . . . . . . . . . . . . . . 70 KIAS.
• 2.3 OCCUPANTS
  All occupants, including the flight crew, must keep their seat belts fastened or being se- cured in another approved manner during flight with door(s) removed or opened.
• 2.4 CENTER OF GRAVITY LIMITS
  With clam shell doors removed, any load may protrude only so far aft that it does not
  reach an imaginary line drawn between the aft end of the skids and the tip of the tail skid. The payload CG shall be located within the cargo compartment and the total helicopter
  CG limits must not be exceeded.

• 2.5.1 Cockpit door(s)
  Opening a cockpit door during flight is permissible only by a crew member not controlling the helicopter and only while performing hover maneuvers (the opened door must be held during flight). For all other flight operations with open cockpit the respective cockpit door(s) must have been removed before flight.
• 2.5.2 Cabin sliding door(s)
  Flight operations at airspeeds greater than 65 kt with opened but installed cabin sliding door(s) are permissible only when the clam shell doors remain installed. Otherwise the respective sliding door(s) must have been removed before flight.
• 2.5.3 Clam shell doors
  For flight operations with open cabin rear entrance both clam shell doors must have been
  removed before flight.
  Flight operations with removed clam shell doors are permissible only when the interior panel installation additional P/N 117-851801 is incorporated and the Sound Isolating Wall (see FMS 10-34, also included in FMS 10-40) is not installed.