g. Handholds can be installed outside the lavatories on the bulkhead walls for use by passengers who may be standing outside the lavatory at the onset of a turbulence encounter.
12. IMPLEMENT IMPROVEMENTS IN DISPATCH PROCEDURES TO PREVENT INJURIES CAUSED BY TURBULENCE.
a. Keep Communication Channels Open Full-time. Dispatchers can communicate with flightcrews, and vice versa before, during, and after a flight, and can be encouraged to do so whenever necessary. In the preflight planning phase, the dispatcher may use the “Remarks” section of the dispatch (flight) release to advise flightcrews of known or forecast turbulence. A “call dispatch” notation on the dispatch release may be included to indicate that the dispatcher believes a telephone conversation with the pilot is necessary. Communication may resume at any time during or after flight using an Aircraft Communication Addressing and Recording System (ACARS), company radio, or telephone – and should be encouraged by an air carrier’s management to improve the flow of real-time information regarding turbulence.
b. Weather Briefings. Preflight weather briefings, verbal or written, must include forecasts of turbulence and pilot reports of turbulence caused by thunderstorm activity, mountain wave activity, clear air turbulence, low altitude frontal windshear and low altitude convective windshear.
c. Real-time Information Sharing. During a flight, the pilot and dispatcher must communicate any changes in the forecast or actual turbulence conditions via voice or digital communication methods in order to pass real-time turbulence information along to other flights.
13. ELEMENTS TO INTEGRATE INTO AIRCRAFT DISPATCHER TRAINING TO PREVENT INJURIES CAUSED BY TURBULENCE. Dispatcher training can include new weather products and services available from private vendors as well as those provided by the National Weather Service (NWS). Continual reinforcement of the turbulence avoidance policy can be evident in theory, in on-the-job training, and in practice as follows:
a. Assure pilot weather briefing includes known areas of turbulence.
b. Discuss flight routing, including en route altitudes, with flightcrew prior to departure.
c. Plan flights so they will not proceed through areas in which thunderstorms of more than moderate intensity are known to exist.
d. Add remarks to dispatch/flight release or weather briefing to emphasize areas where turbulence may be expected.
e. Plan flights to avoid areas of severe turbulence.
f. Plan flights to avoid areas with severe thunderstorms.
g. Add remarks to dispatch/flight release to emphasize areas of turbulence that can be avoided.
Par 11 Page 7
14. THREE FUNDAMENTALS OF EFFECTIVE PRACTICES AGAINST TURBULENCE.
a. Turbulence Avoidance as Corporate Culture. The first and most fundamental step in developing effective practices is for an air carrier to adopt a corporate culture of avoidance of turbulence as the first line of defense. Implementing a turbulence avoidance culture can include SOPs for dispatch and flight operations providing for rerouting around forecast and observed turbulence, and for observing standard clearances between thunderstorms and aircraft.
b. Rerouting. In the past the practice of rerouting has been met with limited air carrier acceptance, primarily because of the inaccuracy of first generation turbulence forecast products, the subjectivity inherent in Pilot Weather Reports (PIREP) (if available), and the operational costs of rerouting. However, recent advances in automation, atmospheric modeling, and data display have improved forecast accuracy, data delivery, and PIREP subjectivity, improving the odds that a well-chosen rerouting would in fact avoid turbulence.
c. Standard Clearances Between Thunderstorms and Aircraft. See Appendix 2.
15. OTHER EFFECTIVE PRACTICES THAT CAN BE USED BY MANAGERS, TRAINERS, METEOROLOGISTS, AND AIRCRAFT DISPATCHERS. Effective practices can include:
a. Use all applicable weather data and products including alphanumeric weather information such as Aviation Routine Weather Reports (METARS), area forecasts and terminal area forecasts (TAF), wind and temperature forecasts, NWS in-flight advisories such as Significant Meteorological Advisories (SIGMETS), Convective SIGMETS and Airman’s Meteorological Information (AIRMETS), upper air charts, graphical radar summaries or composites, and satellite imagery.
b. Use sophisticated product generation to merge diverse sources into graphical product to track turbulence.
c. Compile turbulence information, including PIREPs, making relevant information easily usable to dispatchers, flightcrews, and air traffic controllers (ATC).
16. NEW SYSTEMS OF TURBULENCE REPORTING AND FORECASTING. Since 1997, major advances in data processing and delivery have allowed graphical depictions of weather to be delivered in near real-time, even to the flight decks of suitably equipped aircraft.
Advanced reporting, forecasting, and delivery of graphics have been promoted by government/industry partnerships and by the leadership of various organizations.
17. ADDITIONAL STEPS TO TAKE TO AVOID TURBULENCE AND THEREBY PREVENT CABIN INJURIES. Continued improvement in turbulence-related weather products requires better handling of real-time information on the state of the atmosphere at any given time. The most promising way to capture and convey this information is through a comprehensive program of reports from aircraft in flight. That program would be founded on automated turbulence reporting supplemented by human reports PIREPs. This system would generate real-time, automatic reports of hazardous turbulence events, and displays the Page 8 Par 14
information for improved operations around turbulence. The report will quantify the severity of the loads experienced in the aircraft’s cabin in accordance with the standard levels of light, moderate, severe, and extreme as described in the FAA’s Aeronautical Information Manual (AIM). These downlinked reports would be displayed on dispatchers’ flight-following display network, and could be scaled and used to predict and inform other aircraft of potential turbulence encounter severity. Reports only would be generated whenever significant turbulence events are encountered.
(1) Air carriers could improve the coverage and objectivity of atmospheric turbulence reports by installing automated aircraft turbulence downlink systems on all ACARS-equipped aircraft.
(2) Air carriers should encourage additional reporting of PIREPs by flightcrews through air carrier PIREPs awareness campaigns and by training flightcrews to follow established PIREPs procedures.
(3) Air carriers could establish communications links and encourage flightcrews to deliver air carrier PIREPs to the NWS and to the FAA.
18. EFFICIENT DELIVERY OF CURRENT INFORMATION. In conjunction with improved turbulence reporting, air carriers may join other industry groups and government organizations to develop faster processing and delivery of current turbulence information, e.g., develop a plan to integrate required improvements in conjunction with normal upgrade/replacement cycles for turbulence detection systems, and/or a cost-effective mix of Internet, Intranet, and other evolving communications systems.
19. ACTIONS TO TAKE TO SUPPORT EMERGING TECHNOLOGIES. Air carriers support development and implementation of emerging technologies when they work with organizations, and equipment manufacturers to develop industry standards for emerging turbulence technologies and weather formats for flight deck display systems.
ORIGINAL SIGNED by James J. Ballough Director, Flight Standards Service Par 17 Page 9
Appendix 1 APPENDIX 1. COMMERCIAL AVIATION SAFETY TEAM (CAST) TURBULENCE
TEMPLATE STANDARD TERMINOLOGY FOR TURBULENCE The following terminology is endorsed by the Commercial Aviation Safety Team, from the Aeronautical Information Manual (AIM) available at http://www.faa.gov/atpubs/.
1. DURATION OF TURBULENCE.
a. Occasional. Less than 1/3 of the time.
b. Intermittent. 1/3 to 2/3 of the time.
c. Continuous. More than 2/3 of the time.
NOTE: Duration may be based on time between two locations or over a single location. All locations should be readily identifiable.
2. TURBULENCE INTENSITY.
a. Light Chop. Slight, rapid, and somewhat rhythmic bumpiness without appreciable changes in altitude or attitude.
b. Light Turbulence. Slight, erratic changes in altitude and/or attitude. Occupants may feel a slight strain against seatbelts. Unsecured objects may be displaced slightly. Food service may be conducted and little to no difficulty walking.
c. Moderate Chop. Rapid bumps or jolts without appreciable changes in aircraft altitude or attitude.
d. Moderate Turbulence. Changes in altitude and/or attitude occur, but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed. Occupants feel definite strain against seatbelts, unsecured objects are dislodged, and food service and walking are difficult.
e. Severe. Large, abrupt changes in altitude and/or attitude. Usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. Occupants are forced violently against seatbelts, unsecured objects are tossed about, and food service and walking are impossible.
f. Extreme. Aircraft is violently tossed about and is practically impossible to control. May cause structural damage.
3. TURBULENCE TYPES.
a. Thunderstorm Turbulence. Turbulence associated within and in the vicinity of thunderstorms or cumulonimbus clouds. A cumulonimbus cloud with hanging protuberances is usually indicative of severe turbulence.
Appendix 1
b. Clear Air Turbulence. High level turbulence (above 15,000’) not normally associated with cumuliform cloudiness. Typically windshear turbulence even when in cirrus clouds.
c. Mountain Wave Turbulence. Turbulence as a result of air being blown over a mountain range or a sharp bluff causing a series of updrafts and downdrafts.
4. PROCEDURES KNOWN TO BE EFFECTIVE AGAINST TURBULENCE. The following procedures have been identified by the CAST and are suggested as standard operating procedures for voluntary implementation by U.S. air carriers. Maximize the information about your flight conditions as follows:
a. Inform air traffic control (ATC) of turbulence at check in with new controller.
b. Inform ATC when unforecasted turbulence is encountered en route.
c. Inform company via ACARS or dispatch frequency so that following flights will be aware of the flight conditions or be planned on another route.
d. Inform/query other aircraft operating in the area on a common frequency.
e. Query ATC about “the rides” when you check in with a new controller/sector.
5. WHEN INFORMED OF TURBULENT FLIGHT CONDITIONS.
a. Prior to departure, seek alternate routing to avoid the affected areas or delay departure until conditions improve.
b. Change en route altitudes or routes to avoid the turbulence.
c. Slow to the manufacturer’s recommended turbulence penetration speed.
d. Prior to descent, seek alternate routing to avoid the affected areas or, if severity dictates, hold or divert to alternate.
e. Avoid any convective activity en route [at or above FL 230] by at least 20 nautical miles and 10 nautical miles below FL 230.
6. GENERAL TURBULENCE PROCEDURES.
a. If flight into forecast turbulence is unavoidable, timely notification to the cabin crew is crucial to their safety.
b. If turbulence is expected before the flight departs, the preflight briefing to the lead F/A must include turbulence considerations. The briefing can be the same as an in-flight briefing for expected turbulence including:
• Actions the captain wants the cabin crew to undertake any time turbulence is expected, Page 2
Appendix 1
• Intensity of turbulence expected,
• Methodology for communicating to the cabin the onset or worsening of turbulence,
e.g., cabin interphone or public address (PA),
• Phraseology for the cabin crew to communicate the severity of turbulence, and
• Expected duration of the turbulence and how an “all-clear” will be communicated.
c. Utilize a positive signal of when cabin crew may commence their duties after takeoff and when they should be seated and secured prior to landing.
d. Passengers will be informed of routine turbulence via the PA system. Do not rely on the seatbelt sign alone.
e. Cabin crew will be informed of routine turbulence via the interphone.
f. If at any time the cabin crew experiences uncomfortable turbulence without notice from the flight crew, they must immediately take their seats and inform the flightcrew.
g. All service items must be properly stowed and secured when not in use.
7. TURBULENCE ONSET CATEGORIES AND INJURY AVOIDANCE ACTIONS.
a. Expected Turbulence. Advance notice exists for the captain to brief the cabin crew either prior to the flight or in-flight via the interphone.
(1) The captain can thoroughly brief the cabin crew on the expected turbulence level and its duration.
(2) Clearly articulate expectations from the cabin crew and request confirmation of completed actions.
(3) Instruct the cabin crew to immediately and plainly report any deviations from the expected turbulence level.
(4) Develop a method to inform the cabin crew of the completion of the turbulence event.
b. Little Warning. Sufficient warning exists to seat the passengers and for the cabin crew to perform their duties.
(1) The captain turns on seatbelt sign and makes a PA announcement, “F/As stow your service items and take your seats. Passengers please remain seated until this area of turbulence has passed and I have cleared you to move about the cabin.”
(2) Cabin crew stows all applicable service items, performs cabin compliance check, and secures themselves in their jump seats.
(3) Lead F/A informs captain of the completion of these items.
Appendix 1
(4) When conditions improve, captain uses the PA system to advise the cabin crew that they may resume their duties and whether or not the passengers may move about the cabin.
c. Imminent Turbulence or Turbulence Occurring. Sudden, unexpected or imminent turbulence requiring immediate action to protect cabin crew and passengers.
(1) Captain turns on seatbelt sign and makes a PA announcement, “F/As and passengers be seated immediately. Passengers please remain seated until this area of turbulence has passed and I have cleared you to move about the cabin.”
(2) Cabin crew take first available seat and secure themselves.
(3) No compliance checks are performed and items are secured only if they present no delay in securing a person in a seat.
(4) When conditions improve, captain makes PA announcement advising the cabin crew that they may resume their duties and whether or not the passengers may move about the cabin.
1/19/06
AC 120-88A Appendix 2 Page 1 (and 2) APPENDIX 2. USAF PRACTICES TO AVOID THUNDERSTORMS AND
ATTENDANT TURBULENCE
1. The practices shown below are excerpted from the United States Air Force Flight Publications for pilots of the Air Mobility Command (AMC).
2. Many of the airplanes operated by the AMC compare closely to the transport category airplanes operated by U.S. air carriers under 14 CFR part 121 in respect to size, weight, and other characteristics. Practices effective in AMC operations are often effective in commercial (air carrier) operations, and vice versa.
3. The following practices have been developed by the Air Force for the AMC pilots as measures to prevent thunderstorm penetrations and to mitigate effects of proximate thunderstorms, especially loss of control and turbulence that might cause injuries.
4. These practices are reprinted here for reference by managers and trainers of pilots operating transport category airplanes in commercial aviation, especially those carrying passengers and F/As under 14 CFR part 121. These practices are comprised of clear and objective criteria to facilitate recognition of cues associated with severe convective activity and guidance to improve flightcrew decisionmaking.
During flight, use any means available to avoid thunderstorms by at least:
• 20 nautical miles [at or above flight level (FL) 230]
• 10 nautical miles below FL 230, in order to minimize exposure to thunderstorm hazards when approaching or departing an airport in an area where thunderstorms are occurring or are forecast
• Attempt to maintain visual meteorological conditions (VMC)
• Maintain at least 5 nautical miles separation from heavy rain showers
• Avoid areas of high lightning potential, i.e., clouds within ± 5,000 feet of the freezing level NOTE: Approaches or departures may be accomplished when thunderstorms are within 10 nautical miles. The thunderstorms must not be producing hazardous conditions (such as hail, lightning, strong winds, gust fronts, heavy rain wind shear, or microburst) at the airport, and must not be forecast or observed to be moving in the direction of the route of flight (to include the planned missed approach corridor, if applicable).
Appendix 3
AAPPPPEENNDDIIXX 33.. GGRRAAPPHHIICCAALL DDEEPPIICCTTIIOONN OOFF SSOOMMEE OOFF TTHHEE DDAATTAA
UUSSEEDD IINN TTHHIISS AACC
TTuurrbbuulleennccee AAcccciiddeennttss PPeerr MMiilllliioonn DDeeppaarrttuurreess UU..SS.. AAiirr CCaarrrriieerrss,, 11998822--22000033
The increase in accidents and injuries cannot be explained only by volume.
The controlling factor might be load factors.
0.2
0.4
0.6
0.8 1
1.2
1.4
1.6
1.8 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 '00 '01 '02 '03
Appendix 3
AAPPPPEENNDDIIXX 33.. GGRRAAPPHHIICCAALL DDEEPPIICCTTIIOONN OOFF SSOOMMEE OOFF TTHHEE DDAATTAA UUSSEEDD IINN TTHHIISS AACC ((CCoonnttiinnuueedd))
TTuurrbbuulleennccee AAcccciiddeennttss PPeerr MMiilllliioonn DDeeppaarrttuurreess UU..SS.. AAiirr CCaarrrriieerrss,, 11998822--22000033
The increase in accidents and injuries cannot be explained only by volume.
The controlling factor might be load factors.
0.2
0.4
0.6
0.8 1
1.2
1.4
1.6
1.8 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 '00 '01 '02 '03 Page 2