If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

RJ1H, en-route, South West of Stockholm Sweden, 2007

From SKYbrary Wiki

Revision as of 14:57, 24 January 2017 by Editor2 (talk | contribs) (Related Articles)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Summary
On 22 March 2007, climbing out of Stockholm Sweden, the crew of a Malmö Aviation Avro RJ100 failed to notice that the aircraft was not pressurised until cabin crew advised them of automatic cabin oxygen mask deployment.
Event Details
When March 2007
Actual or Potential
Event Type
Airworthiness, Human Factors, Loss of Control
Day/Night Day
Flight Conditions VMC
Flight Details
Aircraft BAE SYSTEMS AVRO RJ-100
Operator Malmö Aviation
Domicile Sweden
Type of Flight Public Transport (Passenger)
Origin Stockholm/Bromma
Intended Destination Gothenburg/Landvetter
Actual Destination Gothenburg/Landvetter
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Climb
ICL / ENR
Location En-Route
Origin Stockholm/Bromma
Destination Gothenburg/Landvetter
Location
Approx. South-west of Stockholm Bromma
Loading map...


General
Tag(s) Inadequate Airworthiness Procedures
HF
Tag(s) Distraction,
Ineffective Monitoring,
Procedural non compliance
LOC
Tag(s) Flight Management Error
EPR
Tag(s) Emergency Descent
AW
System(s) Air Conditioning and Pressurisation,
Oxygen
Contributor(s) Maintenance Error (valid guidance available),
Inadequate Maintenance Schedule,
Component Fault in service
Outcome
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation,
Aircraft Technical
Safety Recommendation(s)
Group(s) Aircraft Operation,
Aircraft Airworthiness
Investigation Type
Type Independent

Description

On 22 March 2007 when limbing out of Stockholm Sweden, the crew of a Malmö Aviation Avro RJ100 failed to notice that the aircraft was not pressurised until cabin crew advised them of automatic cabin oxygen mask deployment.

Summary

This is the Summary from the report published by the Swedish Accident Investigation Board:

"The events consist of two independent incidents, where the second incident was a consequence of the first. The events have therefore been described here as the first incident and the second incident respectively.

The first incident

The aircraft taxied out at Stockholm/Bromma airport for a scheduled flight to Gothenburg/Landvetter Airport. Due to the changing weather conditions, the switches for the aircraft’s de-icing system and air conditioning system (which among other things pressurises the cabin) were switched on and off at various points during the take-off and climb out. The climb checklist did not contain any specific item for checking the air conditioning unit (“pack”) switches, which control the pressurisation of the cabin, only a summary item in respect of the air conditioning system in general. At about 10000 ft3,048 m
the “Avionics fan off” warning light lit in the cockpit. The pilots began to read the emergency checklist for this warning, which may among other things be initiated by low air pressure, but there were no instructions for checks or measures to be taken related to this warning. At about 18000 ft5,486.4 m
one of the cabin crew called and said that the oxygen masks above the passenger seats in the cabin had dropped down. The pilots discovered that the aircraft cabin was not pressurised and immediately began to descend to a safe altitude. The aircraft had reached an altitude of 19000 ft5,791.2 m
before the descent began. During the descent, the warning light for high cabin altitude came on, that according to the specifications should have warned the pilots when the cabin altitude exceeded 10 000 feet. On investigation it was found that the relevant pressure sensor was damaged. The reason why the aircraft climbed to about 19 000 feet without the cabin being pressurised was that the checklist was not defined clearly enough. A contributory factor was that the inspection interval for the cabin low pressure sensor was probably too long.

The second incident

When the oxygen masks dropped from above the passenger seats, the cabin crew could see that a large number of masks on the left side had not dropped. After checking the status of the pilots the chief cabin attendant went along the cabin without oxygen and started to move passengers from the left side to the right side of the aircraft. Shortly afterwards the chief cabin attendant was given a portable oxygen bottle by a colleague and together they tried to open more hatches with oxygen masks for the passengers. A small tool that is meant for manually opening the hatches could not be found during the incident. The oxygen pressure at an altitude of 19 000 feet is only about half the pressure at sea level, and results in an equivalent reduction of the oxygen level in the blood. Human reaction to this depends on the individual, but even at low altitudes the effects of oxygen deprivation can become apparent in the form of a lowering of both physical and mental capacity. The reason why 20 of the oxygen mask hatches did not open was that the company’s quality control was deficient in connection with the repacking of the hatches.

Recommendations

The Swedish Civil Aviation Authority is recommended to:

  • Ensure that, within applicable areas of civil commercial air transport, checks on the status of the pilots and the institution of cabin-cockpit communication are introduced as obligatory items in the cabin staff emergency checklists in the case of an unannounced decrease of cabin pressure (RL 2008:01e R1).

It is recommended that EASA:

  • Takes steps to ensure that the inspection interval for cabin pressure sensors in this particular type of aircraft is reduced (RL 2008:01e R2).
  • Takes steps to ensure that the emergency checklist in this particular type of aircraft is complemented with a note in the respect of checking cabin pressure when the “Avionics Fan Off” warning is activated while airborne (RL 2008:01e R3)..."

Related Articles

Aircraft Technical

Human Factors

LOC

General

Further Reading

For further information see the full Report published by the Swedish Accident Investigation Board (SHK).