ALPA Submission re CMR 3272VIII. WB-120 AIRCRAFT AIRSPEED GUIDANCE
This section is intended to highlight the fact that, at the time of the CMR 3272 accident, there was no Minimum Maneuvering Speed guidance provided to EMB-120 flightcrews.
Also, subsequent to the CMR 3272 accident and based upon a review of he previous six (6) EMB-120 icing induce upsets, the FAA issued an NPRM regarding icing operations in the EMB-120 aircraft. This NPRM was issued in May of 1997. As part of this NPRM, and a subsequent Airworthiness Directive (AD), a minimum speed in icing conditions was provided. The FAA did not address the concept of minimum maneuvering speeds but simply generated a single minimum airspeed for all aircraft configurations. This FAA defined airspeed lacks technical justification and may not protect the aircraft in aII conditions. Comair
5 subsequently generated and provided minimum maneuvering speed guidance to their Bightcrews.
Tbis section will also identify several conditions where, currently and in spite of the existing AD, Bightcrews of the EMB-120 aircraft are provided guidance to operate below the minimum maneuvering speed identified by the FAA.
Conclusions: .
A.
At the time of the CMR 3272 accident, there was no guidance available to flightcrews regarding minimum operating speeds in icing conditions. The FAA issued AD 97-NM-46-AD in December of 1997 (11 months after accident) in which a minimum airspeed in icing conditions was provided (160 kts). AD 97-NM-46-AD did not mention or address minhnmn maneuvering speeds for various aircraft configurations as the NTSB recommended. There is currently guidance in EMB-120 flightcrew manuals, which direct them to operate at airspeeds below their minimum maneuvering speeds in daily aircraft operations under specific conditions or failure modes.
REFERENCE SPEED GUIDANCE
The Comair Flight Standards Manual (FSM), Section 7 is entitled Maneuvers and Procedures. At the time of the accident, this section of the FSM did not make any reference to minimum maneuvering speeds for various aircraft configurations. A minimum maneuvering speed is normally
5 based on the stall speed for the particular configuration and weight, and provides a guaranteed protection from stall up to a specific bank angle. Since the CMR 3272 accident however, Comair has provided these speeds to their EMB-120 flightcrews.
In spite of the airspeed guidance provided by either the FAA or Comair, there are several conditions where EMB-120 flightcrews are provided conflicting guidance that directs them to operate at airspeeds well below the minimum airspeed provided by the FAA. Those are summarized below:
40
Take-Off (Reference pp. 4-22 of AFM and pp. 7-32,7-35,36 of FSM): After take-off and during the initial climb, the aircraft is accelerated to V2 + 20 kts prior to flap retraction. For an aircraft weighing 24,000 lb. (the approximate weight of CMR 3272) V2 is computed, per Comair’s charts, to be 113 knots. At 133 knots, which is V2+20, the flaps are then retracted and the aircraft is accelerated to its “final segment airspeed (V,) and climbed to 1500 ft. Vfs for an aircraft weighing 24,000 lb. is 143 knots. There are no maneuvering restrictions for operation at this airspeed for this segment of the climb.
.
Flap Control Fault (Reference pp. 3-45 of AFM, pp. 4-54,55 of FSM): The checklist for a Flap Control Fault calls for adding 35 knots to the reference speed for flaps 45 (Vrcr 45) when flaps are at 0 degrees. This is the most conservative case. For an aircraft weighing 24,000 lb., V,f 45 is 112 knots and Vref 45+ 35 knots is 147 knots. Again, there are no maneuvering restrictions for operation at this airspeed under this failure condition.
Stall Speed (Reference pp. 5-27 of AFM): For an aircraft weighing 24,000 lb., the stall speed is computed to be 114 knots. This speed is for an aircraft in a clean configuration (i.e. gear and flaps up).
The above instances demonstrate the inconsistent airspeed guidance provided to EMB-120 flightcrews. EMB-120 crews operate this aircraft daily according to established procedures at speeds at or less than those airspeeds where ice induced roll upsets have occurred.
ALPA has noted that, in this case and with respect to numerous other Part 25 turboprop aircraft, minimum-maneuvering speeds for all configurations are not published. This is in direct contrast to jet transports, in which a weight-dependent minimum maneuvering speed is published for each flap conf&uration. ALPA believes this to be inconsistent with the safe operation of these aircraft and inconsistent with the concept of One Level of Safety. .
41
. A . . . .
..” . . . . . . -. ..r-LYYnCa \ -‘-‘------
AIRPLANE FLlGHT.MANUAL 2 -??=- TAKEOFF
Power Levers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADVANCE Advance the power levers until the torque indication match the calculated static takeoff torque. For rolling takeoff, set power levers to approximatelly 75% of torque determined bv power setting chart on runway alignment and advance up to takeoff power, before reaching 50 KIAS during takeoff run.
NOTE: During takeoff run. pedals should be used to steer the airplane.
Engine Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MONITOR During takeoff run, Np digital indication may oscillate up to 2%. depending on wind speed. This characteristic should disappear after takeoff.
At VR. rotate the airplane smoothly to 7O. At V2 t 10 KlAS and 35 ft height, with positive rate of climb:
Landing Gear Lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . UP
At V2 t 20 KIAS and level off height: F&I Selector Lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . UP
ubae
Accelerate to Final Segment Airspeed. t/ fS
NOTE: When at or near critical field length. static takeoff technique may be accomplished. In this~ case, release brakes after engine has reached the calculated static takeoff torque. The torque reading may increase during takeoff, which is normal. During the climb beyor.. 40011 AGL. if necessary, readjust the torque to the calculated static torque setting.
- TAKEOFF CHECKLIST COMPLETED -
Maneuvers and Procedures
.‘, :.... . .*
.,
Maneuvers and Procedures
8. At V,, the Pilot Flying will rotate the aircraft to approximately 7 degrees pitch attitude.
9. When a positive rate of climb is established, the PiIot Not Flying will call, posifiw me. The Pilot Flying will confhm a positive rate of climb and call, geur up.
IO. The Piiot Not Flying wig sekt the gear up position and call, in rrantir, and continue monitoring engine and flight instruments. The Pilot Not Flying will then call, gear up.
I I. Unless a Standard Instrument Departure procedure directs otherwise, maintain runway heading until reaching 400 feet AGL or Obstruction Clearance Attitude.
If departing a Special Use Runway, an immediate turn may be performed after reaching 50 feet AGL using an airspeed of V2 + 10 with a bank angle not to exceed I5 degrees.
12. AI 400 feet AGL or Obstacle Clearance Altitude, the Pilot Not Flying will call, 400, V2 + 20. The Pilot Flying will verify V2 + 20 and mpond. jlaps up. climb powr, climb
check.
01 MAY 94 (REV. Reissue)
.1 wr EMB-120 FLIGHT STANDARDS MANUAL
Maneuvers and Procedures
13. The Pilot Not Flying will confirm flaps up; slowly set climb power, and perform the Climb checklist.
I NOTE I
Np may be Iefl II 100% until level off or reduced Lo 90% a~ 12.OCtl F&c MSL depending upon lhe climb profile desired. Normally. If climhmg Lo or &cw FL 180. Ibe Np should be reducecf to 90% at 12,CKM feei.
14. At 1,500 feet AGL, the Pilot Flying will establish a climb profile of 180 KIAS to 10,000 feet.
120 FSM 7-3s 01 MAY 94 (REV. Reissue)
. . . .
OPERATIONS MANUAL For airplanes Post-Mod SB 120-022-0020 or S/N 120.154.120.162,120.162 and on, when the AP/FD enters the Altitude Preselect Capture phase the system will maintain the ALT ARM annunciation.
NOTE: - If during this phase the pilot changes the preselected altitude value. the AP/FD systems will revert to basic pitch mode and the ALT annunciator will drop off. To capture a new preselected altitude the pilot should reset the APlFD modes.
- For airplanes Post-Mod SB 12Og22-0620 or S/N 120.154,120.162,120.182 and on, during altitude preselect capture phase. a “knob-in-motion” signal or a vertical mode change causes the system to retumto Altitude Preselect Arm phase. The ALT SEL mode will still be operative, but the vertical mode will remain off. The APlFD may or may not capture the new altitude depending on the attitude of the airplane.
C. ALTITUDE PRESELECT TRACK - There is no indication to the pilots when the Autopilot/Flight Director systems go from the Altitude Preselect Capture phase to Altitude Preselect Track phase. However, this transition normally takes approximately 30 seconds. In this phase. the pilots can change the preselected altitude value without affecting the Autopilot/Flight Director operation. When the altitude is captured. the system automatically engages the altitude hold mode. For airplanes Post-Mod SB 120-022-0020 or S/N 120.154, 120.162. 120.182 and on, when the AP/FD goes into Altitude Preselect Track, the annunciation will go from ALT ARM to ALT.
- DESCENT MODE (DSC)
Prior to selecting DSC mode. the desired altitude should be selected on the Altitude Preselector. When descent mode is selected, the autopilot will begin a gradual descent. stabilizing at an average rate of 2000 feet per minute. The pilot may vary the rate of descent bv operating the vertical trim switch. The DSC and ALT ARM annunciators go on when the mode is selected.
- CLIMB MODE (CLIMB1
.Prior to selecting CLIMB mode, the desired altitude should be selected on the Altitude Preselector. When CLIMB mode is selected. the autopilot begins a gradual climb, stabilizing at an indicated airspeed defined by the climb profile. This profile is:
- 155 KIAS up to 20000 ft. then decreasing by approximately 2 kt/lOOO ft to 135 KIAS at 32000 ft. for airplanes equipped with autopilot computer P/N 6228315302 MOD 67.G.
- 170 KIAS at SL decreasing to 155 KIAS at 20000 ft. maintaining 155 KIAS above 20060 ft. for airplanes equipped with autopilot computer P/N 6228135402 MOD 71.G.
NOTE: Airplanes S/N 120.287. 120.288. 120.290 and on have the autopilot computer P/N 6228135402 MOD 71.6 factory incorporated.
12 AUGUST 199(
ABNORMALPROCEDURES
I NOTE I
Do not exceed the VFE 01 the most extended pair of llaps. VFE for intemwdiate pOSitions is the nexl higher llaps setting limit.
Landing Reference Speed correction vakms:
Flaps posltlon Correction Indicator
45 VREF + 5 KIAS
Correction values given above have been increased by 5 knots for flaps positii greater than 14 degrees, IO prevenl Hall warning system actuation.
The GPWS aural warning may be deactiiated by pulkng the GPWS 1 circuit breaker.
I CAUTION I
The unfactored landing distance will be increased by
73% _....._._................... llaps 0 lo 14 degrees 30% .,....___._._...__._....., flaps 15 lo 44 degrees 5% ._......._..___._._.................. flaps 45 degrees
These increments should be applied on Ihe landing distance lor Naps 45 degrees.
120 FSM 4 - 55 01 OCT 95 (REV. 7)
~.c.:.:.~: : &yd-ggfiANuaL FLIGHT CONTROLS FAILURE (Continued)
ABNORMAL PRDCEWRES
(Electronic fault in the control channel(s) not involving disagreement or asymmetry).
INDICATION: - FLAP & ADVANCED SWS lights on multiple alarm panel.
- CONTROL FAULT light on Flap Warning Indication panel.
- CONTROL FAULT indication on annunciator panel alphanumeric display (if applic- able).
- Affected flap pair(s) light bars flashing on flap annunciator panel.
l Verify Normal Radio Master Switch ON.
l Verity flap position on flap position indicator
NOTE: Flap position indication may not be valid after the RST button is pressed.
l Press RESET (RSTI button momentarily.
l If successful, flap selector lever may be used as required.
l If unsuccessful, leave the flap selector lever in the last selected position.
l Land as soon as practical. For VREF correction assume the flap position indicated before the RST button pressing.
NOTE: l Do not exceed the VFE of the most extended pair of flaps. VFE for intermediate positions is the next higher flaps setting limit.
e Landing Reference Speed correction values:
Flaps position indicator Correction
0” to 14O VREF 45 + 35 KIAS 150 to 44O VREF 45 + 15 KIAS 45O VREF 45 + 5 KIAS
Correction values given above have been increased by 5 kt for flaps position greater than 14O. to prevent stall warning system actuation.
l The GPWS aural warning may be deactivated bY pulling the GPWS 1 circuit breaker.
CAUTION: THE UNFACTORED LANDING DISTANCE WfLLBE INCREASED BY 73% (FW’Sg”TO 14”). 30% [FLAPS 15O TO 44O) AN0 5% (FLAPS 459. THESE INCREMENTS SHOULD BE APPLIED ON THE LANDING DISTANCE FOR FLAPS 45”.
CTA APPROVED
OCTOBER 26.1990
ABNORMAL PROCEDURES
(Electronic fault in the control channel(s) not involving disagreement or asymmetry).
. FLAP (L ADVANCED SWS lights on Multrple Alarm Panel.
. CONTROL FAULT light on Flap Warning Indication Panel. .
l CONTROL FAULT indication on Annunciator Panel Alphanumeric Display.
l Attected flap pair(s) light bars flashing on Flap Annunciator Panel.
Verity Normal Radio Master Switch ON.
Verity tlap position on flap position indicator.
I NOTE I
Flap position indiiatiin may no1 be valrd atter the RST button IS pressed.
Press RESET (RST) button momentarily.
If successful, flap selector lever may be used as required.
If unsuccesstul. leave the flap selector lever in the last selected position.
Land as soon as practical.
For VRFF correction, assume the hap position indicated before pressing the RST button.
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