Date: 201505
Local time of day: 1801-2400
Location: TPA.Airport, FL
Flight conditions: IMC
Weather elements / visibility: Rain; Thunderstorm; Turbulence
Light: Night
Aircraft: SF 340B
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B TPA
ATC / advisory: Tower TPA
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Anomaly: Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Diverted; Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action
Contributing factors: Procedure; Weather; Human Factors
Primary problem: Weather

Narrative: Weather received with flight release prior to departing for TPA visibility was greater than 6 miles; wind variable at 3 KTS; clear forecast for time of arrival. Release included no alternate airport. Considering the weather report available at that time; an alternate airport was not required. Enroute TPA; ZJX Center advised of thunderstorms developing in the TPA area. Captain (pilot monitoring) left Comm 1 to the flying pilot and called Dispatch to obtain an amendment to the flight release indicating MCO as the alternate airport for the flight. Upon arrival in KTPA area; Approach controllers requested keep 'speed up' and expressed confidence that the 'Popup thunderstorm' would quickly dissipate and/or depart the vicinity of TPA. Just prior to switching to Tower frequency; the initial Approach Controller advised that a MD 88 had just landed TPA reporting minimum visibility due to rain but a smooth ride. Thereafter; TPA Final Approach Controller issued instructions to increase speed for in-trail traffic and cleared Aircraft X for ILS 1L approach; 'Maintain 170 KTS until five-mile final.' We Intercepted glide-slope at 2600 feet with autopilot engaged in approach mode. In order to comply with ATC instructions; initial descent on the GS was conducted with the aircraft in 'Clean' configuration at 170 KTS. When we switched to Tower frequency; the Tower Controller alarmed; 'Windshear Alert! 20 knot change in wind speed on the runway and a wind direction change from 320 to 270.' Pilot monitoring verbalized; 'That's on the runway. We'll be down by then (sic). We can continue.' At approximately 1700 feet; pilot flying requested configuration for landing and Landing Checklist slowing the aircraft to approximately 140 KIAS. As Pilot monitoring flipped switches; made PA; and read the landing checklist; aircraft encountered wall of water associated with thunderstorm over TPA. Pilot flying noted and verbalized increase in airspeed in excess of 20 KTS stating; 'That was more than a 20 knot increase in airspeed! We need to break-off this approach!' Pilot monitoring appeared to note airspeed indications; that the autopilot was engaged; and that the current airspeed corresponded to autopilot maintaining GS despite significant updrafts. At about the same time; Tower Controller transmitted; 'The aircraft ahead reported airspeed deviations of 20 KTS on final and just broke off its approach.' Before we could respond; to the Tower an aircraft on approach behind us interrupted to check-on the frequency and advise the Tower Controller that it had just experienced a 20 knot increase in airspeed and intended to break off its approach. Just then; we encountered another 15 knot [plus] increase in airspeed. At that point; we declared our intention to break off the approach requesting immediate turn to avoid further penetration into the thunderstorm. Tower responded with instructions for left turn to heading of 330 and a climb to 3000 feet. Pressing TOGA on the power levers positioned the flight director nose-up. The pilot flying pushed the power levers forward; asked for max power; initiated climb; asked for flaps 7; noted increase in airspeed indication and climb indication on the VSI; turned toward the desired heading (heading bug had been set by the pilot monitoring) and requested gear up prior to 150 KIAS. When pilot flying verbalized that the FD indicated a turn indication opposite the desired direction; the pilot monitoring pressed the FD mode sector on the autopilot control panel stowing the distraction. We found clear air about five miles from the airport. The crew discussed fuel quantity; considered the fuel consumption effect of another approach attempt... followed by another missed and then a flight to the alternate in trail of several other aircraft that were also likely to also be deviating at that time. Upon receiving additional information from the TPA Approach Controller that the once dissipating thunderstorm now appeared to be building in intensity once again and 'Boiling' over TPA; Aircraft X departed immediately for its alternate; MCO. At least two air carriers and a couple other aircraft diverted to MCO. One B737 aircraft opened that it had plenty of fuel and elected to hold for several minutes. A corporate jet aircraft requested to hold over 'Airshow' to keep an eye on the thunderstorm with expressed intent to advise ATC when ready for approach. The request was denied. The explanation given was that too many aircraft were being diverted through that airspace. Consequently; the jet expressed its intention to divert to LAL. Aircraft X diverted to and landed at MCO without further adventure. Following a personal after-action analysis; and a review of Aircraft X subject matter pertaining to the events; the pilot flying has concluded that a unique cascade of errors lead Aircraft X to commence an approach into severe windshear in violation of company policy. The errors included: -Absence of reliable forecast weather data available to the dispatchers and to the flight crew before the flight departed. -Failure of the flight dispatch process to assure timely monitoring of changing airport conditions throughout the conduct of the flight from departure and prior to the arrival of Aircraft X at TPA.-The initial; intermediate and final approach controller's assurances that the thunderstorm appeared to be local in nature; temporary; dissipating; and moving away from TPA; issuing instructions to 'Keep your speed up;' combined with rapidly changing weather conditions; and miscommunication between the TPA Tower Controller and TPA Approach controllers that were handling the flight. A Flight Dispatcher must monitor the progress of each flight under that Dispatcher's control until the flight has landed or until the Dispatcher is relieved by another Flight Dispatcher and must keep the PIC or any other party involved in operational control notified of any significant weather change that could present a challenge to safety of flight. Flight monitoring; at a minimum; must consist of the monitoring of each flight's fuel state; flight time remaining; destination and alternate airport weather trends; enroute winds and weather (including Pilot or other reports reflecting clear air turbulence; thunderstorms and low level windshear); and the status of airport and navigational facilities.The power of a thunderstorm is extreme and the potential for placing your aircraft; crew and passengers into a hazardous situation is very real. Turbulence; windshear; heavy rain; lightning; ice and hail are all associated with thunderstorms. Crews will use all available resources to detect and avoid thunderstorms.Windshear Avoidance1. Carefully assess all available information such as pilot reports of windshear or turbulence; low-level windshear alerts (LLWSA) and weather reports including thunderstorm activity. Avoid areas of known windshear.2. Severe windshear is that which produces un-commanded airspeed changes greater than 15 knots. If severe windshear is indicated; do not takeoff or continue an approach until conditions improve. Report any windshear encounters precisely and promptly. Whenever a pilot reports windshear; controllers are mandated by regulations to advise other pilots.If windshear conditions with airspeed variations of +- 15 knots from the stabilized approach speed are encountered; a go around should be initiated.




Synopsis: SF340 First Officer reports departing for TPA with a clear forecast and no alternate required. Enroute developing thunderstorms are reported and an alternate is requested from Dispatch. During the approach; a 20+ knot speed increase is noted and heavy rain is encountered. Aircraft ahead and behind the SF340 break off their approaches and this crew soon follows and diverts to their alternate.