No doubt about it, the air traffic controller used non-standard phraseology and that was the first link in the chain that led to this mishap. The controller instructed: "Tiger 66, descend two four zero zero. Cleared for NDB approach runway three three." The pilot heard "descend to four zero zero" and read back: "Okay, four zero zero." The correct phraseology would have been: descend and maintain two thousand four hundred feet" from the controller and the pilot.
— James Albright
The pilot's Situational Awareness should have told him that was a ridiculous altitude for any part of the approach until just prior to landing. (They impacted 6.5 nm from the runway.)
The first officer was flying and had earlier complained about not having an approach plate, which the captain dismissed. The first officer was not assertive and it isn't clear if he had protested the altitude but there was evidently a lack of Crew Resource Management between the two pilots.
We as pilots can reduce the confusion level by forever banning the words "to" and "for" from our read backs. See the "Never Say To and For" technique in Clearance Read Back.
Note: There isn't a lot available about this accident on line; I pieced this together from the best that I could find. I do have the names of three references, shown below, but not the references themselves. If you have a copy of any of them, or anything else about this accident, please send them to me using the "Contacts" button on this page.
- Date: 19 FEB 1989
- Time: 06:36
- Type: Boeing 747-249F
- Operator: Flying Tiger Line
- Registration: N807FT
- Fatalities: 4 of 4 crew
- Aircraft Fate: Destroyed
- Phase: Approach
- Airports: (Departure) Singapore-Changi International Airport (SIN) (SIN/WSSS), Singapore; (Destination) Kuala Lumpur Subang International Airport (KUL) (KUL/WMKK), Malaysia
The Boeing, named "Thomas Haywood", was less than half loaded with textiles, computer software and mail when it departed Singapore. Approaching Kuala Lumpur, the crew were cleared to route direct to the Kayell (KL) beacon for a runway 33 approach. While on the NDB approach, the crew were cleared to ". . . descend two four zero zero . . ." which was interpreted by the crew as ". . . to 400 . . .". The aircraft descended below minimum altitude and crashed into a hillside at 600 feet/180m msl just before reaching the Kayell NDB, where minimum descent height was 2400 feet. The Boeing hit treetops and started to break up until bursting into flames.
Cockpit Voice Recorder
CA = Captain
FO = First Officer
FE = Flight engineer
TWR = Kuala Lumpur Tower
GPWS = Ground Proximity Warning System
CA - alright just hit the ah KL then make your turn to three three zero and ah I will give you the-
SOUND OF CHIME
FO - down the line on the checklist
SO - okay, do you want the INS's now?
CA - whatever
FO - how in the hell does he expect us to find the runway...
CA - hit KL beacon and turn to two two nine and I'll give the ah...
TWR - tiger six six descend-- (two/to) four zero zero cleared for NDB approach runway three three
FO - NDB, that son of a bitch
CA - okay four zero zero
CA - alright go ahead I'll set ya up
CA - you got them all set up right now two five five and three five five and ah- twenty nine after- three twenty nine inbound
CA - okay
FO - i think they're not set up like that
CA - yeah you got'em set up-
FO - no they're not
CA - two five five three five five
FO - no
CA - you got two five five
FO - three thirty eight
CA - alright
FO - i got two five five and we need three five five
CA - two five five and okay I'll give you three five five over here
CA - alright you got it
CA - you by there three twenty nine
SO - hopefully you won't
FO - screw this stuff lets go over and do an ILS
CA - we can do-
FO - i haven't even got the damn plate in front of me
CA - you're alright just keep on goin' down to four hundred feet
CA - two five five- still goin' to KL beacon it's on, it's on yours
CA - we go down you feel uncomfortable we don't break out we'll make a missed okay
FO - okay
CA - lookin' good
SOUND OF ALTITUDE ALERT TONE
SO - gear's down tilt checks nav and auto flight panel
SOUND SIMILAR TO FLAP HANDLE BEING MOVED
FO - let's go all the way on the checklist
SO - speedbrake
CA - set
SO - you want any kind of brakes?
CA - ah-
FO - yeah let's put the brakes on-
CA - ah put them on minimum
SO - okay
SO - they're givin' eight thousand meters of visibility at this time
SO - flaps
GPWS - WHOOP WHOOP PULL UP
CA - so you got
GPWS - WHOOP WHOOP PULL UP
CA - so you got the ILS set- right?
FO - yeah
CA - I'm gunna put you on fourteen seven and that'll give you-
GPWS - WHOOP WHOOP PULL UP (sounds 5 times)
? - oh
SO - I've got a hundred feet on the-
? - shit
GPWS - WHOOP WHOOP PULL U-
SOUND OF IMPACT
END OF RECORDING
The aircraft was assigned a non-directional beacon (NDB) approach to Runway 33 at Sultan Abdul Aziz Shah Airport, Kuala Lumpur, after having flown 30 minutes from Singapore Changi Airport. In descent, the flight was cleared to "Kayell" with a morse code of "KL" of which four separate points on the ground were commonly called by Malaysian ATC albeit with different frequencies. Two separate radio beacons were identically coded "KL" as well as the VOR abbreviation (Kuala Lumpur shortened to "KL") and the airport was also sometimes referred to as "KL" by local ATC (instead of the full "Kuala Lumpur"). The crew was unsure to which point they were cleared, and the cockpit voice recorder revealed that the crew argued about which radios should be set to which frequencies and which approach was actually going to be conducted. (Even in the last few moments of the flight, the captain referenced the ILS approach for runway 33 which was named as inop on the flight release and the ATIS, additionally the crew was told by ATC that the ILS approach was not available.)
ATC radioed to the flight, "Tiger 66, descend two four zero zero [2,400 ft], cleared for NDB approach runway 33." Captain Halpin, who heard "descend to four zero zero" replied with, "Okay, four zero zero" (meaning 400 ft above sea level, which was 2,000 ft too low). The Cockpit voice recorder also revealed several communication errors made by the flight crew prior to this miscommunication and a general casual nature of the Captain, who was the pilot-not-flying on this particular leg of the trip.
During the final approach, numerous clear warnings were given by the on-board Ground Proximity Warning System which were all ignored entirely by the crew, and the aircraft impacted a hillside 437 ft above sea level, killing all four people on board; two pilots, a flight engineer and an aircraft mechanic. The subsequent fire burned for two days.
The First Officer had complained that he did not have an approach plate in front of him and had not seen the approach. From a pilot's perspective, this alone would be considered the cause of the crash because the approach plate (chart) provides the pilot with the courses and minimum altitudes necessary to execute the approach without impacting terrain. The chart would have indicated the minimum descent altitude of 2,400 feet, preventing the accident.
Additionally, the First Officer (FO), who was the pilot flying at the time, expressed concern about conducting the NDB approach and indicated a preference for the ILS for runway 15. However, the FO was not assertive and no further action was taken. The Captain dismissed his concern saying he was familiar with the airport and the approaches.
Non-standard phraseology was used by Kuala Lumpur ATC, causing the crew to misinterpret the instructions.
There isn't a lot available on line about this accident. If you have a copy of any of the following, please send them along and I can expand further.
- Aviation Week & Space Technology 27.02.89 (24)
- Flight International 17-12 January 1990 (p.44)
- ICAO Adrep Summary