Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are indicated airspeed, calibrated airspeed, equivalent airspeed, true airspeed, density airspeed. Indicated airspeed is what is read off of an airspeed gauge connected to a pitot static system, calibrated airspeed is indicated airspeed adjusted for pitot system position and installation error, equivalent airspeed is calibrated airspeed adjusted for compressibility effects. True airspeed is equivalent airspeed adjusted for air density, is the speed of the aircraft through the air in which it is flying. Calibrated airspeed is within a few knots of indicated airspeed, while equivalent airspeed decreases from CAS as aircraft altitude increases or at high speeds. With EAS constant, true airspeed increases as aircraft altitude increases; this is because air density decreases with higher altitude, but an aircraft's wing requires the same amount of air particles flowing around it to produce the same amount of lift for a given AOA.
The measurement and indication of airspeed is ordinarily accomplished on board an aircraft by an airspeed indicator connected to a pitot-static system. The pitot-static system comprises one or more pitot probes facing the on-coming air flow to measure pitot pressure and one or more static ports to measure the static pressure in the air flow; these two pressures are compared by the ASI to give an IAS reading. Indicated airspeed is the airspeed indicator reading uncorrected for instrument and other errors. From current EASA definitions: Indicated airspeed means the speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors. Outside the former Soviet bloc, most airspeed indicators show the speed in knots; some light aircraft have airspeed indicators showing speed in statute miles per hour or kilometers per hour. An airspeed indicator is a differential pressure gauge with the pressure reading expressed in units of speed, rather than pressure.
The airspeed is derived from the difference between the ram air pressure from the pitot tube, or stagnation pressure, the static pressure. The pitot tube is mounted facing forward. Sometimes both pressure sources are combined in a pitot-static tube; the static pressure measurement is subject to error due to inability to place the static ports at positions where the pressure is true static pressure at all airspeeds and attitudes. The correction for this error is the position error correction and varies for different aircraft and airspeeds. Further errors of 10 % or more are common. Calibrated airspeed is indicated airspeed corrected for instrument errors, position error and installation errors. Calibrated airspeed values less than the speed of sound at standard sea level are calculated as follows: V c = A 0 5 minus position and installation error correction. Where V c is the calibrated airspeed, q c is the impact pressure: the difference between total pressure and static pressure, P 0 is 29.92126 inches Hg.
Units other than knots and inches of mercury can be used. This expression is based on the form of Bernoulli's equation applicable to isentropic compressible flow; the values for P 0 and A 0 are consistent with the ISA i.e. the conditions under which airspeed indicators are calibrated. Equivalent airspeed is defined as the airspeed at sea level in the International Standard Atmosphere at which the dynamic pressure is the same as the dynamic pressure at the true airspeed and altitude at which the aircraft is flying; that is, it is defined by the equation 1 2 ρ 0 2 = 1 2 ρ 2 where ρ is the density of air at the altitude at which the aircraft is flying. EAS is a measure of airspeed, a function of incompressible dynamic pressure. Structural analysis is in terms of incompressible dynamic pressure
1995 Alaska Boeing E-3 Sentry accident
The Alaska Boeing E-3 Sentry accident was the 22 September 1995 crash of a United States Air Force Boeing E-3 Sentry airborne early warning aircraft with the loss of all 24 people on board. The aircraft, serial number 77-0354 with callsign Yukla 27, hit birds on departure from Elmendorf Air Force Base in Alaska, United States. With the loss of thrust from both of the left engines the aircraft crashed into a wooded area less than a mile from the end of the runway; the Sentry was being operated by the 962d Airborne Air Control Squadron and was scheduled for a training sortie with the callsign Yukla 27. The aircraft was to depart from runway 06 and was waiting while a Hercules transport aircraft took off ahead of it. With its crew unaware that the Hercules had disturbed a flock of Canada geese, the Sentry lined up and started its departure roll; as the E-3 rotated it ingested multiple birds into its number 1 and 2 engines. The crew started to dump fuel and initiated a turn to the left to return to the airfield, but with a full fuel load and having lost two engines on the same wing, it was unable to maintain altitude.
After the aircraft reached 250 feet it descended and crashed into a hilly, wooded area, exploded. The investigation concluded that the probable cause was the ingestion of Canada Geese into the number 1 and 2 engines. Other factors included the insufficient efforts of the air base to deter the birds, the failure of the air traffic control tower to report to both the Sentry and the airfield management that birds were present on the airfield; the sequence of events during impact was determined. The aircraft struck the ground nose first and slid to the top of a hill, where the empennage broke off. "As the cleared the second hill, it rolled over. The fuselage broke up as the rolled; the outboard right wing impacted on the left side of the wreckage, the right-hand wing broke off and the rotodome section impacted on its back, breaking up the rest of the aircraft."Investigators reviewed the flight and wreckage path of the accident aircraft. "The lifted off and flew before contacting trees," the report said.
"The flew before making contact with the ground and crashing in a fireball." The Boeing E-3 Sentry serial number 77-0354 was built as an E-3A variant with the Boeing construction number 21554 and line number 933. It first flew on 5 July 1978 and was delivered to the United States Air Force on 19 January 1979, it was modified by Boeing to E-3B standard. This aircraft was used on the first day of the Desert Storm air war, with its crew controlling the intercept and shootdown of four Iraqi fighter aircraft in far western Iraq; the aircraft was involved in the 14 April 1994 Black Hawk shootdown incident in Iraq, during which its crew were controlling two F-15 fighter aircraft that shot down a pair of US Army UH-60 Blackhawk helicopters, killing 26 military and civilian personnel. Yukla 27 website Airborne Early Warning Association website Notes Sources
Nigeria Airways Flight 357
Nigeria Airways Flight 357 was a scheduled domestic passenger flight from Yola Airport in Yola to Murtala Muhammed International Airport in Lagos, with stops at Jos Airport in Jos and Kaduna Airport in Kaduna. On 13 November 1995, the Boeing 737-2F9, during its second leg of the flight from Jos to Kaduna, suffered a runway overrun accident at Kaduna Airport, leading to a fire that destroyed the aircraft. All 14 crew members survived; the aircraft was a Boeing 737-2F9 registered in Nigerian registration code 5N-AUA. The aircraft was equipped with 2 Whitney Canada engines, it had its first flight on 14 October 1982. Manufactured in Renton, U. S. A and had a construction number of 22985, it was manufactured on 11 February 1983; the aircraft had the airframe time of 22,375.40 hours. The Captain was a 43 year old Nigerian male with a Nigerian issued Airline Transport Pilot Licence Number 2911 valid until May 1996, he had his command ratings on Cessna-150 and Piper Aztec. As at the time of the accident, the Commander had a total flying experience of over 6,000 hours of which over 4,000 hours were on type.
The Commander was qualified to take the flight. While the First Officer was a 39 year old Nigerian male with a Nigerian issued Commercial Pilot Licence Number 2884, valid until midnight of 13 November 1995, his part 2 ratings were Boeing-737 and Boeing-727. The First Officer had a total flying experience of over 5,000 hours out of which 3,000 hours were on type, he was found qualified to take the flight that day. Before the fatal Jos - Kaduna sector, the aircraft had flown from Yola to Jos; the first and third sectors of the flight were flown by the Captain, while the first officer was on the controls for the second sector of the flight. They both had problems with the flight controls in these sectors; the aircraft landed at Yola at 21:00 UTC for a night stop and the crew arrived at their hotel by 22:00 UTC. Flight 357 took off from Yola Airport at 07:30 UTC for Kaduna, carrying 138 people on board with an adequate fuel; the Captain stated that the official crew members were eight in number and the extra six persons were boarded at his discretion and that of the Station Manager.
The Estimated Time of Arrival at Kaduna is 07:46 UTC. Kaduna gave Flight 357 an inbound clearance for approach onto runway 05. Though, the initial landing clearance was for runway 05, the Captain requested to land on runway 23, he was reminded by the Air Traffic Controller that the wind was from 090 magnetic, but he still insisted on using the 23 approach. The Captain, accepted to land with a tailwind. Flight 357 commenced its initial descent at 07:42 UTC and was cleared to 3.500 ft. It descended to 500 ft; the crew tried to align the aircraft with the runway. The First Officer asked the Captain "Can you make it to land from that position?" An observer in the cockpit suggested going on the downwind. However, there was no response at all from the Captain and the approach was continued for runway 23; the left turn was steep and it took the aircraft to the left of the runway centreline and a right correction was applied. The observer had to shout a warning "Watch the wing" as the wings could have struck the ground on the final approach.
The crew were still struggling with the plane's control to align it with the runway. The aircraft touched down at 2020 ft from the end of the paved runway 05 after consuming 79.5% of the runway total length. The Captain was reported to have used 1.6 EPR on the reversers. When a runway overrun became inevitable, the Captain turned the aircraft to the left with the intention to take advantage of the last rapid exit intersection to avoid the runway end lights. At this juncture, the aircraft entered an uncontrollable skid; the attendant turning moments forced the right wing to hit the ground, thus rupturing the fuel tanks and a huge fire erupted. Passengers and crews tried to escape the fiery wreckage. 66 people were injured in 14 of them seriously. 11 passengers on board were killed. Final report Nigerian Federal Ministry of Aviation
Verona Villafranca Airport
Verona Villafranca Airport known as Valerio Catullo Airport or Villafranca Airport, is located 10 km southwest of Verona, Italy. The airport is situated next to the junction of A4 A22 Modena-Brenner motorways, it serves a population of more than 4 million inhabitants in the provinces of Verona, Brescia and Trentino-Alto Adige/Südtirol. Villafranca Air Base was a military airport during the First World War, it became open to civil traffic in the early 1910s with daily scheduled connections to Rome and charter flights to destinations in northern Europe. Towards late 1970s, under the first community project by the Province of Verona, Comune of Verona and the local Chamber of Commerce, Villafranca Airport constructed a passenger terminal and handling facilities; the managing society, "Aeroporto Valerio Catullo di Verona Villafranca S. P. A.", was established in December 1978. Ownership is shared between provincial governments from Veneto, Lombardy and Alto Adige/Südtirol. In 1990, the passenger terminal was expanded in order to cope with the growing air traffic.
The aircraft apron and car-parking areas were enlarged. In 1995, the airport has reached a record of handling one million passengers per annum. In 1999, the airport became Italy's second-grade airport in the'Special Classification of Charter Traffic' and ranked after Milan Malpensa Airport and Rome Fiumicino Airport. During the Bosnian War, the airport was used by NATO aircraft as a staging area. Passenger numbers continued to grow: 2 million per year in 2001 and 3 million per year in 2006. In response to the strong demand in patronage, the airport has undertaken a significant expansion programme on its services and facilities. In May 2006, a new arrivals terminal, Terminal 2, was opened by the Vice-Minister of Transport, Cesare De Piccoli, Vice-President of Veneto Region, Luca Zaia; this additional terminal is situated next to the original building, now known as Terminal 1. As a result of the expansion programme, the airport's capacity has doubled. Hence Terminal 1 is used for departures and Terminal 2 for arrivals.
Air traffic has continued to grow during the 2010s with 3,385,794 passengers recorded in 2011. After a European Union investigation into high subsidies being granted to Ryanair on their scheduled routes, the airline pulled out of Villafranca Airport in 2012; this caused a reduction in passenger traffic in 2013. In 2015, Ryanair reintroduced services to the airport with scheduled flights to Palermo, London Stansted and Brussels. Several airlines have switched their charter routes to regular services during the Winter Season 2015-16: Finnair flies between Verona and Helsinki and AirBaltic flies between Verona and Riga; the route between Paris and Verona, as operated by Air France, ceased operation in late October 2015, having been replaced with flights operated by its low-cost subsidiary, Transavia. Verona-Villafranca Airport is equipped with a fog-dispersal device, which remains the best solution available in Italy and abroad to date, so that flight operations could continue during times of low visibility.
This system allows pilots to land in visibility as low as 75 m. The runway is certified for ILS Category IIIb approach; the two terminals and arrivals, are situated next to each other. The departures hall hosts check-in facilities at the eastern side; the lounge is located on the first floor's eastern wing. The main bus stand is located directly outside the arrivals hall. A shuttle bus service, Aerobus operated by ATV, connects Verona-Villafranca Airport directly with Verona Porta Nuova station. During the summer months, ATV buses 164, 183 and 184 additionally provide hourly connections between Verona-Villafranca Airport en route to comunes along Lake Garda/Lago di Garda. Media related to Verona Airport at Wikimedia Commons Official website Current weather for LIPX at NOAA/NWS Accident history for VRN at Aviation Safety Network
Ansett New Zealand Flight 703
Ansett New Zealand Flight 703 was an Ansett New Zealand scheduled passenger transport flight from Auckland Airport to Palmerston North. On 9 June 1995, the de Havilland Canada Dash 8 aircraft flying this route crashed into hilly terrain in the Tararua Ranges, 16 km east of Palmerston North airport, during an instrument approach in bad weather; the aircraft was carrying three crew members. All passengers were New Zealand citizens except for one United States citizen; the flight attendant and three passengers died as a result of the crash. The aircraft, registration ZK-NEY, a de Havilland Canada DHC-8 Dash 8, was manufactured in Canada in 1986. During the approach to a right turn which would place the aircraft on final approach to runway 25, the right landing gear failed to extend so the co-pilot began to manually extend it using a hydraulic pump; the aircraft's power settings had been reduced to Flight Idle, normal, but the aircraft was inadvertently allowed to descend too low toward the undulating terrain leading into Palmerston North.
The initial impact with terrain occurred at 1,272 feet above sea level. Although Flight 703's Ground Proximity Warning System sounded an alarm four seconds before the aircraft hit the ground, the crew was unable to avoid the accident. According to the Transport Accident Investigation Commission report, an audio alarm telling the crew to climb the aircraft should have sounded 17 seconds before impact, but the GPWS malfunctioned, for reasons that have never been determined. There was an investigation by the New Zealand Police in 2001 into whether or not a mobile phone call from the aircraft may have interfered with the system; the official crash report does mention the following on page 69: "The aircraft manufacturer's avionics representative advised that there was no likelihood that the operation of a computer, other electronic device or a cell phone would have affected the aircraft's flight instruments." The captain's defence was that 4.5 seconds before impact the radar altimeter display flipped 1,000 feet in altitude as he watched.
Flight 703 pancaked onto a hilltop and broke up as it slid along the ground, killing the flight attendant instantly. Passenger Reginald John Dixon tried to free two others trapped near the wing root as the wreckage caught fire, he failed to free them and a flash fire critically burned him. He died from his injuries two weeks later. Thus, three passengers died and many others sustained injuries. For his bravery in a dangerous situation, Dixon was awarded the New Zealand Cross, New Zealand's highest award for civilian bravery. Study of the wreckage of Flight 703 revealed that the antennas for the radar altimeter had been painted and this reduced the GPWS' ability to provide a timely alarm, although comments by TAIC insisted the paint did not block or reflect signals. Radar altimeter antennas are embossed with the words, "do not paint", a warning, not heeded. Bench testing of the radar altimeter proved the unit was still functioning after its recovery from the wreckage. Air New Zealand Flight 901 List of accidents and incidents involving commercial aircraft New Zealand National Airways Corporation Flight 441 Dash 8 Down: the Inside Story of Ansett Flight 703.
ISBN 1-86941-489-6. Guerin, Michael.
1995 Royal Air Force Nimrod R1 ditching
On Tuesday 16 May 1995, a Royal Air Force Nimrod R1 aircraft suffered an in-flight engine fire which led to the aircraft having to ditch in the Moray Firth. The aircraft involved was XW666, one of three specially converted Nimrod aircraft for use in the SIGINT gathering mission; the aircraft, operated by 51 Squadron, first flew in 1973, before being delivered to the RAF for entry into service in late 1974. At the time of the accident, the aircraft had undergone a major service at the Nimrod Major Servicing Unit at RAF Kinloss in Moray; as a result of its serial number, XW666 was unofficially referred to as "The Beast", "Damian" owing to its connotation as the Number of the Beast. On 16 May 1995, following the completion of major servicing work, XW666 had departed RAF Kinloss on a routine air test flight with a crew of seven on board. Thirty-five minutes into the flight, after a test of the anti-icing system, the fire warning light of number 4 engine came on. At this, the crew began the fire drill procedures but, while this was taking place, the warning light for the number 3 engine illuminated.
Following this, a member of the crew confirmed that the aircraft was indeed on fire, with panels falling from the starboard wing. At this point, the captain, who had attempted to divert back to Kinloss, elected to instead try and ditch the aircraft in the Moray Firth, as it was unclear whether the structural integrity would hold, whether control could be maintained any longer. Despite the lack of flaps, which were not functional due to hydraulic failure associated with the fire, the pilot was able to make a controlled ditching on the waters of the Moray Firth; this caused the fuselage to break into two pieces, which sank. Following an inquiry by the Air Accident Investigation Branch and the RAF, it was determined that the DC loom on the aircraft's Number 4 engine had somehow sustained damage prior to the flight. An arc occurred when the anti-icing system was turned on, which led to the engine air start sequence initiating; the engine was running idle as part of the testing regime during the flight, so when the starter turbine ran up to high speed, it caused a structural failure that led to the turbine disc puncturing one of the fuel tanks.
The fuel leak was subsequently ignited, either by the high engine temperature, or the arc from the faulty loom. Owing to the fact that the Nimrod was not an ordinary MR2 maritime patrol aircraft, but rather one of the RAF's specialised SIGINT reconnaissance aircraft, the procurement of a replacement was given the highest priority. By 13 June 1995, four weeks after the crash, the Government had approved what became known as Project Anneka, after the BBC programme Challenge Anneka, with a budget of up to £30m. A stored MR2 was selected for conversion to R1 standard, after which it was serviced, before having its ASW equipment removed and a full set of the secret communications intelligence and electronic intelligence gathering equipment installed; the installation work and testing was completed by 28 April 1997, the new aircraft was delivered to 51 Squadron. 2006 Royal Air Force Nimrod crash
Sommacampagna is a town and comune in the province of Verona, northern Italy. As of 2017, its population was of 14,746; the town was founded with the name of Summa Campanea. In the frazione of Custoza two battles were fought during the Italian Independence Wars: the first in 1848 and the second in 1866; the municipality is part of the urban area of Verona and borders with Sona, Valeggio sul Mincio and Villafranca di Verona. It counts the hamlets of Custoza; the town's most famous sagra is called "Antica Fiera di Sommacampagna" and takes place every year during the last weekend of August from Thursday to Tuesday. Sommacampagna is served by the A4 motorway at the homonym exit, it counts a railway station on the Milan-Venice railway, the Airport of Verona-Villafranca is located in its municipal territory, nearby Caselle. The town's main football team is Associazione Calcio Somma. Gidino di Sommacampagna, poet Federico Bricolo, politician Hall in Tirol, Austria Sommacampagna official website Sommacampagna on tuttocitta.it