Airworthiness Directive · Amendment 39-11827 · Bell Helicopter Textron Canada Model 407 Helicopters
Bell Helicopter Textron Canada Model 407 Helicopters
Superseded. A later AD replaced this one: AD 2001-01-52. Comply with the one in force.
Model 407 helicopters, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 407 helicopters. That AD requires installing a tail rotor pitch-limiting left-pedal stop (pedal stop), installing an airspeed limitation placard, marking a never-exceed velocity (Vne) placard on all airspeed indicators, and revising the Limitations section of the Rotorcraft Flight Manual (RFM). This AD requires installing a redesigned tail rotor system and modifying the vertical fin and horizontal stabilizer to allow restoring the Vne to 140 knots indicated airspeed (IAS). This AD is prompted by design changes to the tail rotor system and modification of the pedal stop for airspeed actuation to eliminate a tail rotor strike to the tailboom. The actions specified by this AD are intended to prevent the tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter.
To prevent the tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before further flight:
(1) Install a stop that limits the maximum distance that the left pedal can travel in accordance with Part I of the Accomplishment Instructions in Bell Helicopter Textron Canada Technical Bulletin 407-98-13, dated December 12, 1998 (TB).
(2) Adjust the rigging of the directional controls in accordance with Part II of the Accomplishment Instructions in the TB.
(3) Install the airspeed limitation placard shown in Figure 1 of this AD so that it completely covers and obscures the airspeed limitation placard, P/N 407-070-201-103. Ensure that the replacement placard is at least 2 1/16 -inches tall and 3 9/16 -inches long.
| Pressure altitude FT X 1000 | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 52 | 98 | 93 | 88 | ||||||||
| 40 | 100 | 95 | 91 | 86 | 81 | 76 | |||||
| 20 | 100 | 100 | 95 | 90 | 85 | 80 | 76 | 71 | 66 | 61 | |
| 0 | 100 | 100 | 100 | 95 | 90 | 85 | 80 | 75 | 70 | 65 | 60 |
| −20 | 100 | 100 | 100 | 100 | 95 | 90 | 85 | 80 | 75 | 70 | 65 |
| −40 | 97 | 93 | 88 | 83 | 79 | 74 | 70 | 65 | 61 | ||
| Maximum Autorotation VNE 100 KIAS |
(4) Install a redline at a Vne of 100 KIAS on all airspeed indicators. Remove or obscure any previously installed lines or arcs above 100 KIAS. If the redline is installed on the instrument glass, also install a slippage mark on the glass and on the instrument case.
(5) Add the following statement to the Limitations section of the Rotorcraft Flight Manual (RFM):
When operating at an airspeed of 60 to 100 KIAS, maintain yaw trim within one ball diameter of the centered position of the turn and bank (slip) indicator, and avoid sudden or large directional control inputs in flight.
(6) Mark the airspeed limitations placard in Figure 1-3 in the RFM to indicate that it has been superseded by this AD, and insert a copy of this AD into the RFM. Also, mark the airspeed indicator in Figure 1-5 of the RFM to indicate a Vne of 100 KIAS.
(7) This AD revises the limitations section of BHTC Model 407 RFM by replacing sheet 1 of Figure 1-3 in the RFM with Figure 1 of this AD, revising sheet 3 of Figure 1-5 of the RFM, and adding an operational limitation for allowable yaw trim and directional control input.
(8) Report any uncommanded right yaw, uncommanded movement of the pedals during flight, or tail rotor blade contact with the tailboom within 24 hours of the occurrence to the Manager, Regulations Group, telephone (817) 222-5111. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.
(b) Before further flight after January 31, 2001:
(1) Remove and replace the existing tail rotor with tail rotor installation, P/N 407-012-100-109, in accordance with Part II of Bell Helicopter Textron Technical Bulletin 407-99-17, dated April 15, 1999.
(2) Modify the vertical fin and horizontal stabilizer in accordance with Bell Helicopter Textron Technical Bulletin No. 407-96-2, Revision A, dated March 11, 1997.
(3) Install the tail rotor airspeed-actuated pedal stop kit, install the new airspeed limitation decals, and remove the temporary instrument markings and RFM changes in accordance with the Accomplishment Instructions in Parts I, II, and III of Bell Helicopter Textron Alert Service Bulletin 407-99-33, Revision A, dated March 10, 2000.
(c) Accomplishing the requirements of paragraph (b) of this AD is terminating action for the requirements of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
